International Journal of Surgical Pathology

Background. To avoid diagnostic errors such as missed diagnosis and errors in staging tumors due to inadequate tissue sampling, pathologists submit additional sections (AS). Objective. This study assessed frequency, diagnostic yield, distribution, and cost of AS. Method. Among 1542 AS cases, we calculated mean AS per case; fraction of AS that altered diagnosis or stage; AS variation by tissue, malignant versus benign lesions, presence or absence of neoadjuvant therapy, mass, margin, lymph nodes, or other source, resident versus pathologist assistant (PA) dissector; and AS cost per case. Results. Overall 9.2 ± 8.8 AS were collected per case. In only 3.8% (58/1542) of cases AS altered diagnosis or stage. Urinary bladder cases provoked the most AS: 19.5 ± 15.1 per case. Significantly more AS came from malignant versus benign lesions (10.8 ± 9.7 vs 7.6 ± 7.5, P = <.0001) and from specimens treated with neoadjuvant therapy versus malignant lesions not so treated (12.3 ± 9.4 vs 10.3 ± 9.8, P = .02). Lymph nodes were sampled more heavily compared with mass, margin, and other sites combined (11.8 ± 11.4 vs 8.9 ± 8.4, P = .003), but in 78.4% (1209/1542) of cases, AS were from mass. Of diagnosis or stage altering AS cases, two thirds (38/58) were from masses, one fifth (11/58) from lymph nodes, a 10th (6/58) from margins, and a 20th (3/58) from other specimen sites. Resident versus pathologist assistant dissection caused no significant AS difference. AS contributed 40% cost per case. Conclusions. AS per case ranged widely; their diagnostic yield was low; they were highest in urinary bladder specimens, in malignant and particularly neoadjuvant-treated lesions. Although lymph nodes were most heavily sampled, most AS were from masses. Resident dissection did not increase AS and cost of AS was high.

Primary sclerosing cholangitis (PSC) is a cholangiopathy—usually associated with inflammatory bowel disease—that leads to cirrhosis and liver failure. Based on a multitude of clinical trials, there is general consensus that PSC progression is unchanged by current therapies, including steroids. However, there are scattered reports in the literature of PSC patients responsive to steroids. Recently, several steroid-responsive PSC mimics have been described, most notably immunoglobulin G4–related sclerosing cholangitis. Following these discoveries, many assume that cases in the literature previously reported as steroid-responsive PSC would now be classified as one of these mimics. We reviewed liver biopsies and the medical histories of patients diagnosed with PSC with documented response to steroids. We identified 3 cases of steroid-responsive PSC in patients with inflammatory bowel disease that do not fit criteria of known PSC mimics. All 3 were adults (age range = 18-44 years) with inflammatory bowel disease, and included 2 males and 1 female. All 3 patients had abnormal liver function tests that normalized on prednisone. Histologically, these 3 cases share a common feature, hepatic fibroinflammatory nodules in a collagen-rich background. They lacked clinical, serologic, and histologic features of immunoglobulin G4–related sclerosing cholangitis. These cases suggest that fibroinflammatory nodules may identify a unique subset of PSC patients who are responsive to steroids.

Objective. Diagnosing melanocytic lesions is among the most challenging problems in the practice of pathology. The difficulty of physically masking melanin pigment and the similarity of its color to commonly used chromogens often complicate examination of the cytomorphology and immunohistochemical staining results for tumor cells. Melanin bleach can be very helpful for histopathological diagnosis of heavily pigmented melanocytic lesions. Although various depigmentation methods have been reported, no standardized methods have been developed. This study developed a fully automated platform that incorporates hydrogen peroxide–based melanin depigmentation in an automated immunohistochemical analysis. Methods and Materials. The utility of the method was tested in 1 cell block of malignant melanoma cells in pleural effusion, 10 ocular melanoma tissue samples, and 10 cutaneous melanoma tissue samples. Our results demonstrated that the proposed method, which can be performed in only 3 hours, effectively preserves cell cytomorphology and immunoreactivity. Results. The method is particularly effective for removing melanin pigment to facilitate histopathological examination of cytomorphology and for obtaining an unmasked tissue section for immunohistochemical analysis.

Background. Umbilical lesions are rare, and can be benign or malignant. This retrospective study was conducted to assess the epidemiological, clinical, and histologic characteristics of umbilical masses. Methods. Cases of umbilical masses from January 1994 to August 2016 were retrieved from our institution’s pathology databases, and their clinicopathological features were reviewed. Results. There were a total of 99 cases of umbilical masses, 78 women (78.8%) and 21 men (21.2%). Of these, 59 were malignant (59.6%) and 40 were benign (40.4%). Among the malignant cases, 48 were women with a mean age of 65 years and 11 were men with a mean age of 66 years. All malignant lesions were secondary tumors. Twenty-five patients (42.3%) had a metastatic tumor to the umbilicus with an average of 7 months from the original diagnosis (12 gynecological, 8 pancreatic/gastrointestinal, 2 lymphomas, and a case each of breast, prostate, and melanoma). Of the patients with a benign diagnosis, 30 were women (75%) with a mean age of 52 years and 10 were men (25%) with a mean age of 43 years. The benign lesions included epidermal inclusion cysts (15/40), endometriosis (11/40), lipomas (3/40), neurofibromas (3/40), fibromas (3/40), abscesses (2/40), and 1 case each of tubular apocrine adenoma, serous cystadenoma, and calcified nodule. Conclusion. The most common metastatic tumors to the umbilicus are from the adjacent organs with the gynecologic tract as the most frequent primary followed by the gastrointestinal system. Primary malignant tumors of the umbilical region are rarely identified in clinical practice.

We report the case of a dedifferentiated solitary fibrous tumor with heterologous rhabdomyosarcomatous differentiation in a 74-year-old male presenting with a rapidly growing, large soft tissue tumoral mass in the gluteal muscles of the right hip. Dedifferentiation in solitary fibrous tumor had not been recognized until very recently and is an extremely rare phenomenon in this tumor type. In the present case, the diagnosis of dedifferentiated solitary fibrous tumor was difficult because of the absence of areas of conventional solitary fibrous tumor with a predominantly poorly differentiated, anaplastic tumor component in the incision biopsy composed of heterogeneous areas with small blue round cell (Ewing sarcoma-like), rhabdoid, epithelioid, and pleomorphic morphology. Moreover, the “unforeseen” strong patchy to multifocal positivity for cytokeratin AE1/AE3 and desmin made the diagnosis of a dedifferentiated solitary fibrous tumor even more challenging in this case. The morphology (presence of branching thin-walled, hemangiopericytoma-like blood vessels) and the immunohistochemical profile (including STAT6 and GRIA2 positivity) were very useful to differentiate this very challenging case of a cytokeratin-positive dedifferentiated solitary fibrous tumor with heterologous rhabdomyosarcomatous differentiation from a broad list of differential diagnoses.

Intravascular large B-cell lymphoma (IVLBCL) is a subtype of diffuse large B-cell lymphoma, where the neoplastic lymphoid proliferation resides predominantly within the lumens of blood vessels but with no or few circulating neoplastic cells in the peripheral circulation. Focal or subtle involvement in some cases can cause the diagnosis to be misinterpreted or even overlooked, delaying the initiation of appropriate treatment. Our report focuses on a 78-year-old woman with a progressively enlarging thyroid mass, verified by ultrasound. She underwent a hemithyroidectomy, and microscopic evaluation demonstrated nodular thyroid parenchyma with atypical large cells in an intravascular distribution pattern identified on high magnification. Thorough evaluation showed that the large intravascular cells were positive CD20, PAX-5, and Ki-67 by immunoperoxidase staining, which lead to the diagnosis of IVLBCL. This case emphasizes the subtle appearance of IVLBCL, which may be missed on low-power light microscopy, and the need for careful evaluation of thyroid resection specimens.

We present a case of a malignant Ewing-like neoplasm of the parotid gland in a 20-year-old woman with an EWSR1-KLF15 gene fusion that presented with pulmonary metastasis. Despite the fact that the tumor was essentially immunohistochemically negative for keratins, p63, and p40, we interpret this neoplasm as an unusual form of a high-grade myoepithelial carcinoma based on its focal plasmacytoid cytology, chondromyxoid matrix, SOX10, S100 protein, and calponin expression, and the knowledge that the EWSR1-KLF15 gene fusion has, to date, only been identified in 2 tumors, both myoepithelial carcinomas of the kidney. We also present a cytogenetic analysis of this unusual tumor. This “Ewing-like myoepithelial carcinoma” initially did not respond to 2 cycles of ifosfamide and etoposide alternated with a cycle of cytoxan, adriamycin, and vincristine, a standard regimen for Ewing sarcoma. Subsequent oral pazopanib therapy did result in a reduction of the patient’s pulmonary and nodal disease.

We report a first case of paraneoplastic human chorionic gonadotropin (HCG) production in a dedifferentiated liposarcoma with rhabdosarcomatous differentiation in an 83-year-old man with a retroperitoneal mass, unilateral scrotal enlargement, and a serum HCG level of 843 IU/L. Core biopsy of the retroperitoneal mass revealed rhabdomyosarcoma. Orchiectomy revealed a paratesticular dedifferentiated liposarcoma with rhabdosarcomatous differentiation. Fluorescence in situ hybridization analysis performed on both the retroperitoneal and paratesticular masses revealed amplification of MDM2. The retroperitoneal tumor was interpreted as metastatic dedifferentiated liposarcoma with the dedifferentiated component represented by rhabdomyosarcoma. HCG production is a common feature of testicular germ cell tumors, less common in carcinomas, and extremely rare in sarcomas. Accordingly, sarcomas secreting HCG are a potential diagnostic pitfall, and raise the differential diagnosis of germ cell tumors and a variety of carcinomas. HCG production by carcinomas is a known poor prognostic finding, however the significance of its production in sarcomas is unknown.

Granulomatosis with polyangiitis is rare in children. We report a case of a 12-year-old male who presented with new symptoms of left eyelid swelling and ptosis. Magnetic resonance imaging showed an enhancing orbital mass suspicious for a neoplasm. Excisional biopsy was performed. Microscopic examination revealed fibrovascular tissue with dense collagenous fibrosis and mixed inflammatory infiltrate that included many plasma cells. Many small and medium-sized blood vessels showed granulomatous and necrotizing vasculitis with disruption of the vessel walls and fibrinoid necrosis. Immunostain for IgG highlighted the numerous plasma cells, approximately 50% of which were positive for IgG4 immunostain. A diagnosis of granulomatosis with polyangiitis was suggested, with recommendation of serologic testing for anti-neutrophil cytoplasmic antibodies. Serum anti-neutrophil cytoplasmic antibodies were borderline high with a cytoplasmic staining pattern. The patient improved with steroid and methotrexate therapy. Granulomatosis with polyangiitis can present as an orbital mass in up to 30% of children. It may be misdiagnosed as IgG4-related disease since the inflammatory background in both conditions may be rich in plasma cells with a high proportion of IgG4+ plasma cells, and accompanied by fibrosis and obliterated blood vessels. The differential diagnosis in this location should also include inflammatory pseudotumor and inflammatory myofibroblastic tumor. Knowledge of this unusual manifestation of granulomatosis with polyangiitis and its diagnostic pitfalls can facilitate early diagnosis and treatment.

Mammary analogue secretory carcinoma (MASC) harboring ETV6 gene rearrangements was first described in the salivary gland with a relatively favorable prognosis and a possible molecular therapeutic target with pan-Trk inhibitors. Recently, primary MASC of the thyroid gland has been reported. We report a case of a 4.0 cm MASC arising from the left thyroid of a 58-year-old female with extrathyroidal extension. Initially, it was diagnosed by fine needle aspiration as suspicious for papillary thyroid carcinoma (PTC) and subsequently called a poorly differentiated carcinoma on resection. A final diagnosis of primary MASC of the thyroid was confirmed after an expanded immunohistochemical panel and identification of an ETV6 gene rearrangement by fluorescence in situ hybridization. Morphologically, the tumor was composed of solid, microcystic and focally papillary growth with dense fibrotic stroma and necrosis. Overlapping cytological features with PTC were identified, including foci of enlarged cells with irregular nuclear membranes/grooves. However, most of the cells contained prominent nucleoli with intraluminal and intracytoplasmic eosinophilic secretions. Immunohistochemically, the tumor cells were strongly positive for pancytokeratin, cytokeratin 7, PAX8, mammaglobin, and GCDFP-15, with rare staining for GATA3 and S100 and negative for TTF-1 and thyroglobulin. We report a rare case of a primary thyroid MASC, initially misdiagnosed as PTC. Pathologists should be aware of this entity and, given the similarities to PTC, have a high index of suspicion, prompting the addition of immunohistochemical and molecular studies. Furthermore, an accurate diagnosis is important because of the possible prognostic and treatment implications.

We report a rare case of pulmonary enteric adenocarcinoma (PEA) exhibiting a immunohistochemical feature of CK7/CK20 double-negativity by evaluating the transformation zone between PEA and conventional pulmonary adenocarcinoma (CPA). A 75-year-old man was found to have a mass, 40 mm in diameter, in the right lower lobe on chest computed tomography, and underwent right lower lobectomy. Histologically, the tumor was composed of a PEA and CPA component. The dominant PEA component had medium to large complex glands with tall columnar cells with eosinophilic cytoplasm and brush-border. The CPA component comprised small to medium glands with cuboidal cells. Moreover, intermediate glands (INT), which had cuboidal to tall columnar cells, with morphological features between PEA and CPA, was also observed in the transformation area. Immunohistochemically, the PEA component was negative for CK7, CK20, and TTF-1, and positive for CDX2 and SATB2 (weak): the CPA component was negative for CK20, CDX2, and SATB2, and positive for CK7 and TTF-1: the INT were negative for SATB2, with intermingled positive signals for CK7, CK20, TTF-1, and CDX2. The final diagnosis was PEA based on the CPA component and not colorectal carcinoma. To distinguish CK7-negative PEA from metastatic colorectal carcinoma, careful examination for a CPA component is very useful along with clinical information. There are no reports that discuss about process of oncogenesis, de novo sequence or transformation from CPA of PEA. This is the first reported case of CK7/CK20 double-negative PEA, with analysis of the transformation zone between PEA and CPA components.

Synovial sarcoma is a ubiquitous neoplasm predominantly affecting soft tissues of young adults of any gender; few cases have been described in the digestive system, mostly in the stomach. The (X;18)(p11.2; q11.2) translocation yields unique SS18-SSX fusion genes. Synovial sarcoma has been related to radiotherapy, but no synovial sarcoma has been associated with the digestive system. This article describes the case of a synovial sarcoma arising along the extrahepatic biliary tree, 10 years after the application of an abdominal radiotherapy schedule due to a retroperitoneal metastatic seminoma in a male who developed progressive obstructive jaundice. Ninety percent of the analyzed cells carried the SS18 gene with separation of sequences, thus denoting a translocation. There are only 8 post-radiotherapy synovial sarcomas that have been reported previously, and this is the first report of a radiotherapy-related synovial sarcoma arising from the extrahepatic biliary tree, and the second case described in this anatomic region.

We present a case of a 4-year-old girl with abdominal angiostrongyliasis who presented with persistent fevers, hepatosplenomegaly, acute abdominal pain, and eosinophilia. Computed tomography scan identified thickening of the ascending colon with a narrowed lumen. Endoscopic evaluation revealed ulcerations and erythema in the ascending colon. The microscopic findings in biopsies included active chronic inflammation with prominent eosinophils and granulomas. A subset of granulomas contained the eggs of Angiostrongylus costaricensis. The definitive method of diagnosing A costaricensis is histology; peripheral blood serology has low specificity and the stool from infected patients does not contain eggs or larvae. Pathologists from endemic regions (Central and South America) are familiar with the typical histologic changes; however, because of increasing global travel, all pathologists should become familiar with A costaricensis, which may mimic common gastrointestinal diseases such as Crohn’s disease, appendicitis, and Meckel’s diverticulum.

A 37-year-old male with long-standing and extensive ulcerative pancolitis developed a rapidly lethal poorly differentiated neuroendocrine carcinoma (NEC) in the sigmoid colon. Prior biopsies obtained from multiple sites of the colon during endoscopic surveillance showed minimal inflammatory changes and no sign of dysplasia. Patients with inflammatory bowel disease (IBD) are at increased risk of colorectal malignancies, and adenocarcinoma is the most common type of colorectal neoplasm associated with ulcerative colitis and Crohn’s disease, but other types of epithelial and nonepithelial tumors have also been described in IBD. NECs arising in the setting of ulcerative colitis are very rare and are reported as anecdotic findings. We describe the clinicopathological features of an IBD-related NEC and review the previously reported cases.