Update June 2018

PURPOSE: Pancreatic cancer is the fourth cause of death by cancer worldwide. Lymph node (LN) involvement is known to be the main prognostic factor. However, lymphatic anatomy is complex and only partially characterized. The aim of the study was to study the pancreatic lymphatic system using computer-assisted anatomic dissection (CAAD) technique and also to update CAAD technique by automatizing slice alignment. METHODS: We dissected three human fetuses aged from 18 to 34 WA. 5-microm serial sections of duodeno-pancreas and spleen blocks were stained (hematoxylin-eosin, hematoxylin of Mayer and Masson trichrome), scanned, aligned and modeled in three dimensions. RESULTS: We observed a rich, diffuse but not systematized lymphatic network in the peri-pancreatic region. There was an equal distribution of LNs between the cephalic and body-tail portions. The lymphatic vascularization appeared in continuity from the celiac trunk to the distal ends of its hepatic and splenic arterial branches parallel to the nerve ramifications of the celiac plexus. We also observed a continuity between the drainage of the pancreatic head and the para-aortic region posteriorly. CONCLUSION: In view of the wealth of peri-pancreatic LNs, the number of LNs to harvest could be increased to improve nodal staging and prognostic evaluation. Pancreatic anatomy as described does not seem to be compatible with the sentinel LN procedure in pancreatic surgery. Finally, we are now able to offer an alternative to manual alignment with a semi-automated alignment.

The lymphatic vasculature act as the drainage system for most of our tissues and organs, clearing interstitial fluid and waste and returning them to the blood circulation. This is not the case for the central nervous system (CNS), which is devoid of parenchymal lymphatic vessels. Nevertheless, the brain is responsible for 25% of the body's metabolism and only compromises 2% of the body's mass. This high metabolic load requires an efficient system to remove waste products and maintain homeostasis. Well-described mechanisms of waste clearance include phagocytic immune cell functions as well as perivascular fluid flow; however, the need for active drainage of waste from the brain is becoming increasingly appreciated. Recent developments in lymphatic vascular biology challenge the proposition that the brain lacks lymphatic drainage or an equivalent. In this review, we describe the roles of the glymphatic system (a key drainage mechanism in the absence of lymphatics), the recently characterized meningeal lymphatic vessels, and explore an enigmatic cell population found in zebrafish called mural lymphatic endothelial cells. These systems may play important individual and collective roles in draining and clearing wastes from the brain.

The etiopathogenesis of infantile hemangioma has not been well understood, and it is accepted that angiogenic mediator dysregulation is the main contributor to the abnormal hemangioma capillary formation. The role of NDRG1, a hypoxia-inducible protein; FOXOs, which are tumor suppressor proteins; and the mTOR complex 2 pathway in infantile hemangioma have not been studied yet. The purpose of this study was to investigate NDRG1 and FOXO1 expression in the infantile hemangioma and the correlation of these proteins with proliferation and involution. This article is protected by copyright. All rights reserved.

Flavonoids, present in fruits, vegetables and traditional medicinal plants, show anticancer effects in experimental systems and are reportedly non-toxic. This is a favorable property for long term strategies for the attenuation of lymph node metastasis, which may effectively improve the prognostic states in breast cancer. Hence, we studied two flavonoids, apigenin and luteolin exhibiting strong bio-activity in various test systems in cancer research and are readily available on the market. This study has further advanced the mechanistic understanding of breast cancer intravasation through the lymphatic barrier. Apigenin and luteolin were tested in a three-dimensional (3-D) assay consisting of MDA-MB231 breast cancer spheroids and immortalized lymph endothelial cell (LEC) monolayers. The 3-D model faithfully resembles the intravasation of breast cancer emboli through the lymphatic vasculature. Western blot analysis, intracellular Ca(2+) determination, EROD assay and siRNA transfection revealed insights into mechanisms of intravasation as well as the anti-intravasative outcome of flavonoid action. Both flavonoids suppressed pro-intravasative trigger factors in MDA-MB231 breast cancer cells, specifically MMP1 expression and CYP1A1 activity. A pro-intravasative contribution of FAK expression in LECs was established as FAK supported the retraction of the LEC monolayer upon contact with cancer cells thereby enabling them to cross the endothelial barrier. As mechanistic basis, MMP1 caused the phosphorylation (activation) of FAK at Tyr397 in LECs. Apigenin and luteolin prevented MMP1-induced FAK activation, but not constitutive FAK phosphorylation. Luteolin, unlike apigenin, inhibited MMP1-induced Ca(2+) release. Free intracellular Ca(2+) is a central signal amplifier triggering LEC retraction through activation of the mobility protein MLC2, thereby enhancing intravasation. FAK activity and Ca(2+) levels did not correlate. This implicates that the pro-intravasative contribution of FAK and of Ca(2+) release in LECs was independent of each other and explains the better anti-intravasative effects of luteolin in vitro. In specific formulations, flavonoid concentrations causing significant anti-intravasative effects, can certainly be achieved in vivo. As the therapeutic strategy has to be based on permanent flavonoid treatment both the beneficial and adverse effects have to be investigated in future studies.

The hyaloid vasculature constitutes a transitory system nourishing the internal structures of the developing eye, but the mechanism of vascular regression and its cell biological characteristics are not fully understood. The present study aimed to reveal the specificity of the hyaloid vessels by a systematic immunohistochemical approach for marker substances of myeloid cells and the extracellular matrix (ECM) in neonatal mice. Macrophages immunoreactive for F4/80, cathepsin D, and LYVE-1 gathered around the vasa hyaloidea propria (VHP), while small round cells in vascular lumen of VHP were selectively immunoreactive for galectin-3; their segmented nuclei and immunoreactivities for Ly-6G, CD11b, and myeloperoxidase indicated their neutrophilic origin. VHP possessed thick ECM and a dense pericyte envelope as demonstrated by immunostaining for laminin, type IV collagen, integrin beta1, and NG2. The galectin-3(+) cells loosely aggregated with numerous erythrocytes in the lumen of hyaloid vessels in a manner reminiscent of vascular congestion. Galectin-3 is known to polymerize and form a complex with ECM and NG2 as well as recruit leukocytes on the endothelium. Observation of galectin-3 KO mice implicated the involvement of galectin-3 in the regression of hyaloid vasculature. Since macrophages may play central roles including blocking of the blood flow and the induction of apoptosis in the regression, galectin-3(+) neutrophils may play a supportive role in the macrophage-mediated involution of the hyaloid vascular system.

Alterations in the intestinal lymphatic network are pathological processes as related to inflammatory bowel disease (IBD). In this study, we demonstrated that reduction in inflammation-induced lymphangiogenesis ameliorates experimental acute colitis. A soluble and stable angiopoietin-1 (Ang1) variant, COMP-Ang1, possesses anti-inflammatory and angiogenic effects. We investigated the effects of COMP-Ang1 on an experimental colonic inflammation model. Experimental colitis was induced in mice by administering 3% dextran sulfate sodium (DSS) via drinking water. We determined body weight, disease activity indices, histopathological scores, lymphatic density, anti-ER-HR3 staining, and the expression of members of the vascular endothelial growth factor (VEGF) family and various inflammatory cytokines in the mice. The density of lymphatic vessel endothelial hyaluronan receptor 1 (LYVE-1) and VEGFR-3-positive lymphatic vessels increased in mice with DSS-induced colitis. We observed that COMP-Ang1-treated mice showed less weight loss, fewer clinical signs of colitis, and longer colons than Ade-DSS-treated mice. COMP-Ang1 also significantly reduced the density of LYVE-1-positive lymphatic vessels and the disruption of colonic architecture that is normally associated with colitis and repressed the immunoregulatory response. Further, COMP-Ang1 treatment reduced both M1 and M2 macrophage infiltration into the inflamed colon, which involved inhibition of VEGF-C and D expression. Thus, COMP-Ang1, which acts by reducing inflammation-induced lymphangiogenesis, may be used as a novel therapeutic for the treatment of IBD and other inflammatory diseases. KEY MESSAGES: COMP-Ang1 decreases inflammatory-induced lymphangiogenesis in experimental acute colitis. COMP-Ang1 improves the symptom of DSS-induced inflammatory response. COMP-Ang1 reduces the expression of pro-inflammatory cytokines in inflamed colon. COMP-Ang1 reduces the expression of VEGFs in inflamed colon. COMP-Ang1 prevents infiltration of macrophages in a DSS-induced colitis model.

Postzygotic mutations of the PIK3CA [phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha] gene constitutively activate the PI3K/AKT/mTOR pathway in PIK3CA-related overgrowth spectrum (PROS) patients, causing congenital mosaic tissue overgrowth that even multiple surgeries cannot solve. mTOR inhibitors are empirically tested and given for compassionate use in these patients. PROS patients could be ideal candidates for enrolment in trials with PI3K/AKT pathway inhibitors, considering the “clean” cellular setting in which a unique driver, a PIK3CA mutation, is present. We aimed to assess the effects of blocking the upstream pathway of mTOR on PROS patient-derived cells by using ARQ 092, a potent, selective, allosteric, and experimental orally bioavailable and highly selective AKT-inhibitor with activity and long-term tolerability, currently under clinical development for treatment of cancer and Proteus syndrome. Cell samples (i.e., primary fibroblasts) were derived from cultured tissues obtained from six PROS patients [3 boys, 3 girls; aged 2 to 17 years] whose spectrum of PIK3A-related overgrowth included HHML [hemihyperplasia multiple lipomatosis; n = 1], CLOVES [congenital lipomatosis, overgrowth, vascular malformations, epidermal nevi, spinal/skeletal anomalies, scoliosis; n = 1], and MCAP [megalencephaly capillary malformation syndrome; n = 4]. We performed the following: (a) a deep sequencing assay of PI3K/AKT pathway genes in the six PROS patients' derived cells to identify the causative mutations and (b) a pathway analysis to assess the phosphorylation status of AKT [Ser473 and Thr308] and its downstream targets [pAKTS1 (Thr246), pRPS6 (Ser235/236), and pRPS6Kbeta1 (Ser371)]. The anti-proliferative effect of ARQ 092 was tested and compared to other PI3K/AKT/mTOR inhibitors [i.e., wortmannin, LY249002, and rapamycin] in the six PROS patient-derived cells. Using ARQ 092 to target AKT, a critical node connecting PI3K and mTOR pathways, we observed the following: (1) strong anti-proliferative activity [ARQ 092 at 0.5, 1, and 2.5 muM blunted phosphorylation of AKT and its downstream targets (in the presence or absence of serum) and inhibited proliferation after 72 h; rapamycin at 100 nM did not decrease AKT phosphorylation] and (2) less cytotoxicity as compared to rapamycin and wortmannin. We demonstrated the following: (a) that PROS cells are dependent on AKT; (b) the advantage of inhibiting the pathway immediately downstream of PI3K to circumventing problems depending on multiple classes a PI3K kinases; and (c) that PROS patients benefit from inhibition of AKT rather than mTOR. Clinical development of ARQ 092 in PROS patients is on going in these patients.

Incomplete delivery to the target cells is an obstacle for successful gene therapy approaches. Here we show unexpected effects of incomplete targeting, by demonstrating how heterogeneous inhibition of a growth promoting signaling pathway promotes tissue hyperplasia. We studied the function of the lymphangiogenic VEGFR3 receptor during embryonic and post-natal development. Inducible genetic deletion of Vegfr3 in lymphatic endothelial cells (LECs) leads to selection of non-targeted VEGFR3(+) cells at vessel tips, indicating an indispensable cell-autonomous function in migrating tip cells. Although Vegfr3 deletion results in lymphatic hypoplasia in mouse embryos, incomplete deletion during post-natal development instead causes excessive lymphangiogenesis. Analysis of mosaically targeted endothelium shows that VEGFR3(-) LECs non-cell-autonomously drive abnormal vessel anastomosis and hyperplasia by inducing proliferation of non-targeted VEGFR3(+) LECs through cell-contact-dependent reduction of Notch signaling. Heterogeneity in VEGFR3 levels thus drives vessel hyperplasia, which has implications for the understanding of mechanisms of developmental and pathological tissue growth.

BACKGROUND AND PURPOSE: Brain arteriovenous malformation (bAVM) is an important risk factor for intracranial hemorrhage. Current treatments for bAVM are all associated with considerable risks. There is no safe method to prevent bAVM hemorrhage. Thalidomide reduces nose bleeding in patients with hereditary hemorrhagic telangiectasia, an inherited disorder characterized by vascular malformations. In this study, we tested whether thalidomide and its less toxic analog, lenalidomide, reduce bAVM hemorrhage using a mouse model. METHODS: bAVMs were induced through induction of brain focal activin-like kinase 1 (Alk1, an AVM causative gene) gene deletion and angiogenesis in adult Alk1-floxed mice. Thalidomide was injected intraperitoneally twice per week for 6 weeks, starting either 2 or 8 weeks after AVM induction. Lenalidomide was injected intraperitoneally daily starting 8 weeks after AVM induction for 6 weeks. Brain samples were collected at the end of the treatments for morphology, mRNA, and protein analyses. The influence of Alk1 downregulation on PDGFB (platelet-derived growth factor B) expression was also studied on cultured human brain microvascular endothelial cells. The effect of PDGFB in mural cell recruitment in bAVM was explored by injection of a PDGFB overexpressing lentiviral vector to the mouse brain. RESULTS: Thalidomide or lenalidomide treatment reduced the number of dysplastic vessels and hemorrhage and increased mural cell (vascular smooth muscle cells and pericytes) coverage in the bAVM lesion. Thalidomide reduced the burden of CD68(+) cells and the expression of inflammatory cytokines in the bAVM lesions. PDGFB expression was reduced in ALK1-knockdown human brain microvascular endothelial cells and in mouse bAVM lesion. Thalidomide increased Pdgfb expression in bAVM lesion. Overexpression of PDGFB mimicked the effect of thalidomide. CONCLUSIONS: Thalidomide and lenalidomide improve mural cell coverage of bAVM vessels and reduce bAVM hemorrhage, which is likely through upregulation of Pdgfb expression.

Chylous ascites (CA) is a rare form of ascites that results from the leakage of lipid-rich lymph into the peritoneal cavity. This usually occurs due to trauma and rupture of the lymphatics or increased peritoneal lymphatic pressure secondary to obstruction. The underlying etiologies for CA have been classified as traumatic, congenital, infectious, neoplastic, postoperative, cirrhotic or cardiogenic. Since malignancy and cirrhosis account for about two-thirds of all the cases of CA in Western countries, in this article we have attempted to reclassify CA based on portal and non-portal etiologies. The diagnosis of CA is based on the distinct characteristic of the ascitic fluid which includes a milky appearance and a triglyceride level of >200 mg/dL. The management consists of identifying and treating the underlying disease process, dietary modification, and diuretics. Some studies have also supported the use of agents such as orlistat, somatostatin, octreotide and etilefrine. Paracentesis and surgical interventions in the form of transjugular intrahepatic portosystemic shunt (commonly known as TIPS), peritoneal shunt, angiography with embolization of a leaking vessel, and laparotomy remain as treatment options for cases refractory to medical management.

RATIONALE AND OBJECTIVES: This study aimed to describe prenatal and postnatal imaging features and outcomes of neonates with neonatal lymphatic disorders (NLDs). MATERIALS AND METHODS: An institutional review board-approved search of the radiology database for patients with NLD identified five patients. Inclusion criteria include prenatal imaging (fetal magnetic resonance [MR] imaging and ultrasound) and postnatal three-dimensional T2 Sampling Perfection with Application optimized Contrasts using different flip angle Evolution (SPACE) and dynamic contrast-enhanced MR lymphangiography within 6 months of life. Chart review was undertaken to evaluate morbidity and mortality. RESULTS: Prenatal finding of “nutmeg lung” or fetal pulmonary lymphatic disorder was identified in all five patients on fetal MR imaging, and in four of five patients on fetal ultrasound. Postnatal dynamic contrast-enhanced MR lymphangiography demonstrated abnormal lymphatic flow to the lungs in four of five patients, but absent in the single patient with coexisting hypoplastic left heart syndrome (HLHS). Dermal backflow was seen in one patient, also the only patient with prenatal body wall edema. Three patients with lymphatic flow to the lungs only were classified as neonatal chylothorax. The patient with dermal backflow and perfusion to the lungs was diagnosed with central lymphatic flow disorder (CLFD). The HLHS patient with normal lymphatic perfusion maintained the HLHS diagnosis. Of the five patients, the patient with CLFD and the one with HLHS expired because of respiratory distress. CONCLUSIONS: NLDs can be recognized on prenatal and postnatal imaging and may be primary, as in neonatal chylothorax or CLFD, or secondary. In this small series, “nutmeg lung” was present in all patients. Prenatal imaging demonstrates that body wall edema may correlate with postnatal dermal backflow, which, in our small cohort, carried a poor prognosis.

For a century-old problem, edema and its treatment have gone remarkably unnoticed by the biomedical community. Given the prevalence of lymphedema and its debilitating repercussions, there is an acute need for both efficacy-based measures and clinical standards to guide compression garment design and therapeutic application. This review outlines the current state of the art in compression treatment and suggests an integrated biomedical engineering approach going forward. Characterizing the pressure gradient profiles of commercial compression sleeves is necessary to better understand the role of compression treatment in the mitigation of swelling. Integration of pressure sensor technologies with advanced materials design and manufacture provides a critical path not only to elucidate the mechanisms of but also to improve on current compression-based therapies and associated therapeutic devices.

PURPOSE: While the normal cornea has limited innervation by the lymphatic system, chronic immune-inflammatory disorders such as dry eye (DE) can induce lymphangiogenesis in the ocular surface. Using a conditional knock-down murine model, Lyve-1(Cre);VEGFR2(flox) mice, this study investigated the role of lymphangiogenesis in the pathophysiology of DE. METHODS: DE was induced in both wild type (WT) B6 and Lyve-1(Cre);VEGFR2(flox) mice. Tissue immunostaining and volumetric gross measurements were used to assess changes in the ocular surface, skin, and lymph nodes (LNs). The expression of lymphangiogenic factors (TNF-alpha, IL-6/-8/-12/-17, VEGF-C/-D, IFN-gamma, VEGFR-2/-3, Lyve-1, and podoplanin) and the frequency of immune cells (CD4, CD11b, and CD207) on the ocular surface and lacrimal glands were quantified by real-time polymerase chain reaction and flow cytometry. RESULTS: Compared to WT mice, there were fewer lymphatic vessels and a reduction in lymphangiogenic markers in the ocular surface and skin of Lyve-1(Cre);VEGFR-2(flox) mice. After DE induction, mRNA levels of TNF-alpha, IL-8, and IFN-gamma were significantly reduced in Lyve-1(Cre);VEGFR-2(flox) mice compared to WT mice (p < .01). Surprisingly, the LNs from Lyve-1(Cre);VEGFR2(flox) mice with DE were significantly smaller and populated by fewer dendritic cells and effector T cells than those from WT mice (p < .001). Furthermore, immunostaining showed corneal nerves in the DE-induced Lyve-1(Cre);VEGFR2(flox) mice were notably intact like in the naive condition. CONCLUSIONS: Inhibition of lymphangiogenesis in the cornea effectively attenuates not only the inflammatory response including trafficking of immune cells but also preserves corneal nerves under desiccating stress. Corneal lymphangiogenesis might be a contributing factor in deterioration on the ocular surface homeostasis.

Inflammatory bowel disease (IBD) is a chronic disease with gastrointestinal dysfunction as well as comorbidities such as inflammation-induced bone loss and impaired immune response. Current treatments for IBD all have negative, potentially severe side effects. We aimed to test whether exogenous treatment with irisin, a novel immunomodulatory adipomyokine, could ameliorate IBD-induced lymphatic and bone alterations. Irisin treatment improved both gut and bone outcomes by mitigating inflammation and restoring structure. In the gut, IBD caused colonic lymphatic hyperproliferation into the mucosal and submucosal compartments. This proliferation in the rodent model is akin to what is observed in IBD patient case studies. In bone, IBD increased osteoclast surface and decreased bone formation. Both gut and osteocytes in bone exhibited elevated levels of TNF-alpha and receptor activator of NF-kappaB ligand (RANKL) protein expression. Exogenous irisin treatment restored normal colonic lymphatic architecture and increased bone formation rate concurrent with decreased osteoclast surfaces. After irisin treatment, gut and osteocyte TNF-alpha and RANKL protein expression levels were no different from vehicle controls. Our data indicate that the systemic immunologic changes that occur in IBD are initiated by damage in the gut and likely linked through the lymphatic system. Additionally, irisin is a potential novel intervention mitigating both local inflammatory changes in the gut and distant changes in bone.-Narayanan, S. A., Metzger, C. E., Bloomfield, S. A., Zawieja, D. C. Inflammation-induced lymphatic architecture and bone turnover changes are ameliorated by irisin treatment in chronic inflammatory bowel disease.

Emberger Syndrome (ES) is a rare genetic disorder characterized by lymphedema and myelodysplasia. It is also associated with hearing loss. The genetic mutations associated with ES are not part of the comprehensive 80 gene next generation sequencing (NGS) panel. As a result, the otolaryngologist should maintain an index of suspicion for ES in any child with SNHL who presents repeatedly with recurrent infections, lymphedema and/or cutaneous warts. This paper describes the clinical evolution and management of two children who were followed up for hearing loss and eventually were diagnosed with ES.

AIMS: We aimed to determine whether cancer-associated fibroblasts (CAFs) are associated with microvessel density (MVD) and lymphatic vessel density (LVD) in lung squamous cell carcinoma, as well as their clinical significance in predicting survival. METHODS: 122 patients were enrolled in the study. Samples were obtained on resection at the Department of Thoracic Surgery of the Qingdao Municipal Hospital between January 2011 and December 2014. Immunohistochemistry was used to determine vessel and lymphatic vessel density, and CAF abundance (fibroblast activation protein alpha (FAP-alpha) positivity). Statistical analyses were performed on 85 patients to test for correlation of CAF density and other clinicopathological variables with 3-year overall survival (OS) and disease-free survival (DFS). RESULTS: High stromal CAF abundance significantly correlated with increased MVD and LVD in lung squamous cell carcinoma (p < 0.05). chi(2) test revealed a significant association of CAF density with lymph node metastasis. Cox proportional hazards model showed that both higher CAF density and lymph node metastasis negatively correlate with survival. CAF density or lymph node status can be used as an independent prognostic factor to predict 3-year OS and DFS. CONCLUSIONS: CAF density, identified by FAP-alpha staining pattern, should be considered as a novel biomarker for disease prognosis in patients with lung squamous cell carcinoma.

A puppy was diagnosed with lymphangiosarcoma associated with lymphedema based on lymphography and histopathology. The lesions resolved after toceranib therapy, and the dog remains in remission 1 year later. This is the first report of a successful outcome following oral toceranib as first-line therapy for lymphangiosarcoma in a dog.

Sentinel lymph node metastasis is a prognostic indicator for systemic tumor spread in many types of cancers, and tumor lymphangiogenesis correlates with reduced survival. Consequently, lymphatic vessels have been suggested to promote tumor progression in multiple ways. Tumor lymphangiogenesis occurs both in primary tumors and at distant (pre-) metastatic sites, and facilitates lymphatic invasion and tumor cell dissemination. Lymphatic vessels have also emerged as regulators of tumor immunity, transporting tumor antigens to lymph nodes and directly interacting with immune cells. Furthermore, lymphatic vessels might provide a ‘lymphovascular' niche contributing to the maintenance of stem-like tumor cells that are tightly related to tumor recurrence. Thus, targeting tumor lymphangiogenesis or specific lymphatic-associated functions might represent a promising approach to inhibit tumor progression.

Lymph node (LN) transplantation is a recognized method for reconstruction of the lymphatic system and is used in the clinical setting to treat lymphedema. However, it is unclear whether transplanted LNs contribute to immune surveillance. In this study, we investigated whether a single transplanted non-vascularized LN, defined as a tumor-draining transplanted lymph node (TDTLN), could exert an immune-mediated antitumor effect. LN and lung metastases and primary tumor enlargement were evaluated in mice that were inoculated with B16-F10-luc2 melanoma cells in a hindlimb footpad without (group 1) and with (group 2) popliteal lymph node (PLN) resection and in mice that underwent LN transplantation after PLN resection (group 3). The function of a TDTLN (group 3) and a tumor-draining popliteal lymph node (TDPLN; group 1) was evaluated in the context of cancer. LN and lung metastases were significantly aggravated by PLN resection but were significantly decreased by LN transplantation. Immunohistochemistry showed that the TDTLNs retained T-cells and B-cells and fluorescence-activated cell sorting analysis confirmed expansion of lymphocytes in these nodes; however, the degree of expansion in TDTLNs was different from that in TDPLNs. Expression of cytokines associated with immunostimulation was confirmed in the TDTLNs as well as in the TDPLNs. One of the differences in the immune-mediated antitumor effect of the TDPLNs and TDTLNs was ascribed to a difference in the site of lymphocyte homing to peripheral LNs through high endothelial venules. Non-vascularized LN transplantation had an immune-mediated antitumor effect. This article is protected by copyright. All rights reserved.

The tumor microenvironment is one of the key factors contributing to the efficiency of drug delivery to a tumor. It has been reported that lymphangiogenesis is induced in certain tumors. Because the lymphatic system functions as a drainage one, it is possible that tumor lymphatic vessels alter not only the tumor microenvironment, but also the distribution of drug nanocarriers accumulated in the tumor tissue. Herein, we aimed to elucidate the involvement of the tumor lymphatic system in the translocation of intratumoral liposomes to regional lymph nodes by using vascular endothelial growth factor (VEGF)-C-overexpressing B16F10 tumor-bearing mice (B16/VEGF-C). When the amount of polyethylene glycol (PEG)-modified liposomes in lymph nodes (cervical, brachial, axillary, and inguinal lymph nodes) was measured after the radiolabeled liposomes had been intratumorally injected into B16/VEGF-C-bearing mice or wild-type B16-bearing mice, the accumulation of liposomes in the axillary and inguinal lymph nodes was significantly higher on the tumor-implanted side of B16/VEGF-C-bearing mice than on that of the B16-bearing ones. On the other hand, the accumulation of liposomes in these lymph nodes on the control side (no implantation) of either type of tumor-bearing mice was very low; and no difference could be observed between the 2 sides. Furthermore, the intratumoral distribution of liposomes was observed to be located near the lymphatic vessels. These results indicate that the tumor lymphatic system contributed to the extrusion of a portion of PEG-modified liposomes from the tumor tissue, suggesting that tumor lymphangiogenesis would be one of the key factors to determine the intratumoral distribution of liposomes and their subsequent fate.

Somatic variants have been well described in tumorigenesis; however, they are only recently appreciated in other human disorders, such as mosaic overgrowth syndromes. Although overgrowth is a manifestation in many genetic syndromes, not all overgrowth syndromes are inherited. Mosaic somatic variants have been lately described in several overgrowth disorders, such as Proteus syndrome, CLOVES (congenital, lipomatous, overgrowth, vascular malformations, epidermal nevi, and spinal/skeletal anomalies and/or scoliosis) syndrome, and megalencephalyepolymicrogyria-polydactyly-hydrocephalus syndrome. These syndromes are caused by somatic variants in the genes associated with the phosphatidylinositol 3-kinase/AKT/mammalian target of rapamycin pathway, resulting in a spectrum of overgrowth syndromes with overlapping features that could be difficult to distinguish based on phenotypic presentations alone. In addition, Sanger sequencing is ineffective for the detection of a causal variant because of the mosaic nature of these variants, whereas targeted next-generation sequencing technology offers a deeper sequencing coverage and allows the detection of low-level mosaicism. Recent studies have shown that the causal variants are only present in the affected tissues in most cases, and can be enriched by in vitro tissue culture. In this review, we describe several mosaic somatic overgrowth syndromes caused by variants in genes of the phosphatidylinositol 3-kinase/AKT/mammalian target of rapamycin signaling pathway, their phenotypic and molecular spectrum, and the clinical utility of next-generation sequencing technology in the diagnosis of these disorders.

Rapidly involuting congenital hemangioma is a subtype of congenital hemangioma. Ulceration and bleeding are rarely reported in rapidly involuting congenital hemangioma, with only four cases reported in the literature to our knowledge. We describe a case of a newborn girl who presented with rapidly involuting congenital hemangioma complicated by ulceration and severe bleeding and discuss treatment.

Recent studies have discovered a group of overgrowth syndromes, such as congenital lipomatous overgrowth with vascular, epidermal, and skeletal anomalies (CLOVES) syndrome, Proteus syndrome, and megalencephaly-capillary malformation-polymicrogyria (MCAP) syndrome, are caused by somatic activating variants in genes involved in the phosphatidylinositol 3-kinase/AKT/mechanistic target of rapamycin pathway. Because of the low-abundance nature of these variants, Sanger sequencing often yields negative results. We have developed and validated a next-generation sequencing (NGS) panel that targets all known variants associated with these syndromes. Fifty cases, including two prenatal cases, were tested using the panel. A pathogenic variant in the PIK3CA, PIK3R2, or AKT1 gene was identified in 28 of the 50 cases with the variant allele frequencies ranging from 1.0% to 49.2%. These variants were only present in the affected tissues in most of the cases, demonstrating a causal role in the development of these diseases. In vitro cell culture showed significant enrichment of the cells harboring variant alleles, suggesting that these variants render growth advantages to mutant cells. Phenotype-genotype correlation analysis showed PIK3CA mutation hotspots at residues E542, E545, and H1047 are often associated with CLOVES syndrome, whereas PIK3CA G914R is preferentially related to MCAP. We thus demonstrate that NGS technology is highly sensitive for detecting low-level mosaicism and can facilitate clinical diagnosis of mosaic overgrowth syndromes in both prenatal and postnatal settings.

Generalized lymphatic anomaly is a rare, complex, lymphatic anomaly generally involving soft tissues, spleen, and bones. It can lead to focal skeletal fragility and pathologic effusions. A recent prospective trial of sirolimus for complicated vascular anomalies showed partial response in seven patients with generalized lymphatic anomaly treated with sirolimus with a target trough level of 10–15 ng/mL for 1 year (Adams et al). We describe successful treatment of generalized lymphatic anomaly with a lower-dose, long-term course of sirolimus.

BACKGROUND: Propranolol is the mainstay of treatment for infantile hemangioma. Despite its good safety profile, it is not risk-free. Guidelines for propranolol initiation and monitoring have been suggested, but protocols vary among practitioners. OBJECTIVE: This study sought to assess the prevalence of adverse events and clinically significant fluctuations in hemodynamic parameters in children with infantile hemangioma during initiation of treatment with propranolol in a day-hospitalization setting. METHODS: Children with infantile hemangioma treated with propranolol in a day-hospitalization department of a tertiary pediatric medical center in 2008–2014 were identified retrospectively. The pretreatment evaluation included clinical examination by a pediatric dermatologist and electrocardiography, echocardiography, and clinical examination by a pediatric cardiologist. The propranolol dosage was escalated from 0.5mg/kg/day to 2mg/kg/day, divided into 3 doses/day, over 3 days. Heart rate, blood pressure, and blood glucose level were measured before treatment onset and 60 min after the first two doses each day. The third dose was given at home. RESULTS: The cohort included 220 children aged 1 month to 5 years. No severe treatment-related adverse events were documented; 27 patients had minor side effects. There was a significant decrease in heart rate each day after the first two doses (p < 0.001), and in systolic blood pressure, on day 2 (1mg/kg/day) after the first dose (p = 0.01). Blood glucose level remained stable. The hemodynamic changes were clinically asymptomatic and did not require intervention. CONCLUSIONS: Propranolol treatment (2mg/kg/day in three doses) for infantile hemangioma is well tolerated and safe and may be administered and monitored in an ambulatory setting. This article is protected by copyright. All rights reserved.

This case report describes a novel presentation of littoral cell angioma (LCA) and lymphatic malformations involving the omentum and mesentery. To our knowledge, these 2 entities have not been reported in the same patient. A 1-month term infant male presented with chylous ascites. During his workup, imaging detected splenic nodules. Biopsies revealed that the nodules were LCA and the chylous ascites was secondary to microscopic mesenteric and omental lymphatic malformations. Evaluation for a secondary malignancy, an underlying immunologic defect, and genetic causes were unrevealing. The presence of LCA and lymphatic malformations in the same patient suggests a genetic link between these 2 rare vascular disorders and may help elucidate the etiopathogenesis of these 2 poorly understood anomalies.

BACKGROUND: Few studies have reported the clinical features, complications and predictors of Kasabach-Merritt phenomenon (KMP) associated with Kaposiform haemangioendothelioma (KHE). OBJECTIVES: To determine the clinical characteristics present at diagnosis and to identify features that may aid clinicians in managing KHE. METHODS: We conducted a cohort study of 146 patients diagnosed with KHE. RESULTS: KHE precursors or lesions were present at birth in 52.1% of patients. In 91.8% of patients, lesions developed within the first year of life. The median age at diagnosis of KHE was 2.3 months (interquartile range 1.0–6.0). The extremities were the dominant location, representing 50.7% of all KHEs. Among KHEs in the cohort, 63.0% were mixed lesions (cutaneous lesions with deep infiltration). Approximately 70% of patients showed KMP. A KHE diagnosis was delayed by >/ = 1 month in 65.7% of patients with KMP. Patients with KMP were more likely to have major complications than patients without KMP (P = 0.023). Young age (< 6 months), trunk location, large lesion size (> 5.0 cm) and mixed lesion type were associated with KMP in a univariate analysis. In the multivariate analysis, only age [odds ratio (OR) 11.9, 95% confidence interval (CI) 4.07–34.8; P < 0.001], large lesion size (OR 5.08, 95% CI 2.24–11.5; P < 0.001) and mixed lesion type (OR 2.96, 95% CI 1.23–7.13; P = 0.016) were associated with KMP. CONCLUSIONS: Most KHEs appeared before 12 months of age. KHEs are associated with various major complications, which can occur in combination and develop early in the disease process. Young age, large lesion size and mixed lesion type are important predictors of KMP. This article is protected by copyright. All rights reserved.

Vascular tumors in infants present a diagnostic and treatment dilemma for both clinicians and pathologists. Infantile hemangioma, the most common vascular tumor in infants, can be confused for other less common vascular tumors in infants. Correct and timely diagnosis is important, as some vascular tumors can be associated with life-threatening coagulopathy. We present the cases of 5 vascular tumors that have clinical and histologic overlap: infantile hemangioma, pyogenic granuloma, noninvoluting congenital hemangioma, tufted angioma, and kaposiform hemangioendothelioma. Typical clinical and histopathologic features of each lesion are summarized. We review the utility and characteristic immunohistochemistry including CD31, CD34, GLUT-1, D2-40, LYVE-1, Prox-1, and WT-1. Collaboration between the clinician and the dermatopathologist correlating the clinical history and histopathologic features can lead to the correct diagnosis, whereas the utility of immunohistochemistry remains in question.

Importance: Patients with vascular malformations (VAMs) and vascular overgrowth syndromes have lower health-related quality of life (HRQoL) attributable to social stigmatization, poor mental health, severity, and pain. However, the factors that contribute to this decreased HRQoL are not clear. Objective: To perform a systematic review and meta-analysis of studies that used validated HRQoL instruments to compare the HRQoL of persons with VAMs with the US general population. Data Sources: A comprehensive search was performed in MEDLINE, Embase, PsycINFO, CINAHL, and Scopus from 1946 to March 31, 2017, with the consultation of an experienced librarian. Study Selection: All VAM studies with validated HRQoL instruments published in the English language were included. Case reports, review articles, non-English-language publications, and studies about the development of new HRQoL instruments were not included. Data Extraction and Synthesis: Two reviewers assessed studies' eligibility and the risk of bias and performed data extraction. The meta-analysis was performed using the random-effects model. Comparisons of means were performed using the unpaired, 2-sample t test. Main Outcomes and Measures: The outcome was HRQoL. Results: Eleven studies met the inclusion criteria for a total of 692 patients with VAMs. Six studies (320 patients) were included in the meta-analysis, whereas 5 studies were included in the qualitative analysis (372 patients). Those with VAMs had lower 36-Item Short-Form Health Survey scores in bodily pain (mean difference, −11.87; 95% CI, −21.45 to −2.29; I2 = 92%; P = .02) and mental health (mean difference, −6.04; 95% CI, −11.55 to −0.52; I2 = 83%; P = .03) compared with the US general population. Conclusions and Relevance: Patients with VAMs had increased pain and psychosocial distress compared with the US general population. Pain and psychological morbidity are associated with poorer HRQoL and may serve as indicators for quality of life.

Sirolimus is an effective therapy for children with kaposiform hemangioendothelioma with or without the Kasabach-Merritt phenomenon. We report the case of a child with kaposiform hemangioendothelioma and the Kasabach-Merritt phenomenon who developed Pneumocystis carinii pneumonia (PCP) while on sirolimus and a prednisolone taper, after lack of adequate response to prednisolone, propranolol, and vincristine. He had a prompt positive clinical and laboratory response to sirolimus, but 4 weeks after starting it, at the age of 4 months, he developed PCP. This led to respiratory failure, which required extracorporeal membrane oxygenation. Sirolimus was temporarily discontinued, and he was successfully treated for PCP with sulfamethoxazole-trimethoprim and methylprednisolone. He was restarted on sirolimus 3 weeks after discharge and given sulfamethoxazole-trimethoprim prophylaxis. At the age of 22 months, while still on sirolimus, the lesion continued to improve with test results revealing stable hemoglobin and platelet counts. PCP is a rare but life-threatening side effect of sirolimus therapy, especially in the setting of concurrent steroid treatment. Pneumocystis prophylaxis should be considered for patients receiving sirolimus.

We describe the case of a 33-week preterm infant who developed nonimmune hydrops fetalis secondary to a kaposiform hemangioendothelioma (KHE). The tumor was successfully treated with vincristine, prednisone, ticlopidine, and aspirin. KHE can be an unusual cause of hydrops fetalis; in such cases, diagnosis can be challenging since generalized edema can obscure KHE.

Infantile choriocarcinoma (ICC) is a rare, highly malignant form of gestational trophoblastic neoplasia. Rapid diagnosis and initiation of treatment are paramount in reaching a successful outcome. Patients with these tumors typically present with a triad of anemia, hepatomegaly, and precocious puberty. Cutaneous manifestations of ICC are extraordinarily rare with few documented cases. Here, we describe a male neonate who presented to our Dermatology clinic with a rapidly growing, markedly vascular glabellar mass associated with abnormal laboratory values suggestive of Kasabach-Merritt phenomenon. The initial clinical impression of infantile hemangioma led to an initial treatment with propranolol. However, the mass continued to enlarge and a biopsy was obtained. Histology revealed a high-grade, poorly differentiated carcinoma. A robust immunohistochemical battery demonstrated tumor reactivity with Glut-1, GATA3, Glypican-3, CAM5.2, and beta-hCG establishing the diagnosis of metastatic choriocarcinoma. The diagnosis was further supported by the elevated serum beta-hCG. In addition to the glabellar mass, imaging demonstrated tumor foci in the liver and lung. Clinical investigation of the mother revealed no evidence of disease.

Various mixed associations between arteriovenous malformations, cavernous malformations, developmental venous anomalies and capillary telangiectasias have been described and a common pathophysiological event has been suggested to be present, although yet to be elucidated. We depict herein the imaging features of a patient who presented with a spontaneous cerebellar hemorrhage, in whom radiological studies demonstrated a pontine telangiectasia, a brainstem/cerebellar developmental venous anomaly and a cerebellar proliferative angiopathy. This unique, not previously reported combination of lesions shows that the spectrum of mixed vascular malformations continues to expand. A pathophysiological mechanism related to the angiogenesis seen in these malformations is also hypothesized.

BACKGROUND: The use of sirolimus for patients with multidrug-resistant Kasabach-Merritt phenomenon (KMP) has been reported in recent years. We present the experience of a single center in treating vincristine-resistant KMP using sirolimus alone. METHODS: Children with vincristine-resistant KMP who were treated with oral sirolimus alone were eligible for inclusion in the study. We evaluated responses according to graded response criteria and acute toxicities according to the National Cancer Institute Common Toxicity Criteria. RESULTS: Between March 2012 and October 2014, eight patients underwent sirolimus treatment. The response rate of hematologic parameters was 100% (8/8). Three tumors shrank enough to allow excision. The tumors were resected after hematologic parameters normalized. Of the five patients with unresectable vascular lesions, three had complete response, and two had partial response of their tumors at the completion of long-term (39.7 +/− 24.4 wks) sirolimus treatment. Grade 3 or 4 adverse events were not documented during treatment or follow-up. No recurrence or progression of the disease was observed during follow-up. CONCLUSION: In this small case series, we found sirolimus to be highly effective, with minimal side effects, for vincristine-resistant KMP. A larger study to compare sirolimus and vincristine for KMP is warranted.

PTEN is a tumor suppressor gene inactivated in over 30% of human cancers. It encodes a lipid phosphatase that serves as a gatekeeper of the phosphoinositide 3-kinase signaling pathway. Germline mutation frequently occurs in this gene in patients diagnosed with PTEN Hamartoma Tumor Syndrome (PHTS). PHTS individuals are characterized by macrocephaly, benign growth of multiple tissues and increased tumor risk. In addition, autistic phenotypes are found in 10–20% of individuals carrying the germline PTEN mutation with macrocephaly. In this report, 13 suspected PHTS patients were screened for mutation in the PTEN gene. A missense variant (c. 302T > C) substituting the isoleucine at codon 101 to a threonine, a single nucleotide insertion (c. 327-328insC) causing a frame shift mutation and termination at codon 109, and a nonsense variant (c. 1003C > T) truncated the protein at codon 335 were identified. The I101T mutation significantly reduced PTEN protein expression levels by 2.5- to 4.0-fold. Mechanistically, I101T reduced the protein half-life of PTEN possibly due to enhanced polyubiquitination at Lysine 13. However, the I101T mutant retained almost 30% of the lipid phosphatase activity of the wild-type protein. Finally, the I101T mutant has reduced phosphorylation at a PTEN auto-dephosphorylation site at Threonine 366 and a lowered ratio of nuclear to cytosolic protein level. These partial losses of multiple PTEN biochemical functions may contribute to the tissue overgrowth and autistic features of this PHTS patient. Autism Res 2018. (c) 2018 The Authors Autism Research published by International Society for Autism Research and Wiley Periodicals, Inc. LAY SUMMARY: The genetics of autism spectrum disorders is highly complex with individual risk influenced by both genetic and environmental factors. Mutation in the human PTEN gene confers a high risk of developing autistic behavior. This report revealed that PTEN mutations occurred in 23% of a selected group of Hong Kong patients harboring autistic features with gross overgrowth symptoms. Detailed characterization of a PTEN mutation revealed reduced protein stability as one of the underlying mechanisms responsible for reduced PTEN activity.

Kaposiform hemangioendothelioma (KHE) is a rare infiltrative vascular tumor that is potentially life-threatening when presenting with Kasabach-Merritt phenomenon (KMP). KMP is clinically characterized as severe thrombocytopenia and hypofibrinogenemia and therefore is associated with a high mortality rate. There is no standard of cure for KHE currently. Potential medications, including corticosteroids, propranolol, and chemotherapy drugs such as sirolimus, are often used for alleviating KHE symptoms. Although some case reports of sirolimus treatment have shown promising results with recovered coagulant parameters, the off-target effects may cause severe problems. Here we describe 2 cases of infant patients with KHE and KMP who were scheduled to receive sirolimus on a long-term basis. However, both patients developed paroxysmal cough and tachypnea shortly after the onset of sirolimus treatment and succumbed to infection thereafter. This report reveals a potential risk of infection in sirolimus-treated infant patients. The fatal complication highlights the importance of antibiotic prophylaxis and serum sirolimus level monitoring to ensure the safe use of sirolimus in the treatment of infant patients with KHE.