Laparoscopic Management of Abdominal Lymphatic Cyst in Children

Introduction

Abdominal lymphatic cysts (ALCs) in children are usually seen in clinical practice as mesenteric (MCs) or omental (OCs) cysts. ¹ The incidence of ALC in children has been reported as being from 1:105,000 to 1:20,000 hospital admissions.^1,2 Laparotomy and complete cyst excision are still considered the standard treatment for ALC in children.^1–5

The first case of laparoscopic excision of MC was reported by Mackenzie et al. ⁶ in 1993. Since then laparoscopic surgery (LS) has been indicated for management of MCs and OCs in numerous centers, but mainly in adults.^7–10 The role of LS for management of ALC in children has not been well defined because there have been only a few reports on laparoscopic management of ALC in pediatric patients.^11–13 The aim of this study is to investigate the safety, feasibility, and effectiveness of LS in the management of ALC in children.

Subjects and Methods

Medical records of all patients undergoing LS for ALC at the National Hospital of Pediatrics, Hanoi, Vietnam, from May 2007 to June 2011 were reviewed. Data about the clinical presentations, diagnosis, intraoperative findings, operative procedures, and results were analyzed. Indication for LS depended on the surgeon's preference.

For LS, one umbilical port of 10 mm and up to three other 3–5-mm ports were used. Cystic fluid was aspirated prior to removal of the cyst. When possible, an OC was delivered out of the abdomen through the umbilical incision, and the cyst was excised extracorporally. When intestinal resection was indicated, the MC with the bowel loop was delivered out of the abdomen through a minimally enlarged umbilical incision, and resection of the intestinal segment together with the cyst and the bowel anastomosis were both performed extracorporally. Abdominal drainage after excision of the cyst was optional.

Results

Forty-seven patients were identified: 25 boys and 22 girls (46.8%), with a mean age of 4.3±3.7 years (range, 1 month–15 years). Clinical presentations were abdominal pain in 34 patients (72.3%), abdominal distention in 16 (34.0%), palpable abdominal mass in 10 (21.3%), abdominal tenderness in 9 (19.1%), vomiting in 8 (17.0%), and fever in 7 (14.9 %). Four patients (8.5%) were admitted with the clinical picture of acute abdomen (2 cases with bleeding MC or OC, 1 case with infected MC, and 1 case of MC associated with omental torsion). Time from onset of symptoms to admission ranged from 3 days to 10 months (median, 30 days). In 2 patients (4.3%) ALC was discovered incidentally by ultrasound for reasons unrelated to the cyst. There were no statistically significant differences between the OC and the MC groups regarding patient's age, gender, and clinical presentation (P>.05).

A preoperative diagnosis of ALC was based exclusively on imaging studies. Ultrasound was performed in all patients, and the most common findings were cystic structure with septa and clear fluid. In 2 cases ultrasound gave a wrong or insufficient diagnosis: a case of MC was diagnosed as bowel duplication, and a case of bleeding OC was diagnosed as ascites. Computed tomography (CT) was performed in 43 patients (91.5%), and even CT misdiagnosed a giant OC as ascites. Forty-five cases (95.7%) had a preoperative diagnosis of ALC. However, in only 20 cases (42.6%) was the exact origin of ALC (omental or mesenteric) identified preoperatively. In the case of bleeding OC, the preoperative diagnosis was hemoperitoneum based on ultrasound and abdominal puncture.

Intraoperatively, MC was found in 35 cases (74.4%) (19 cases of small bowel MC, 9 cases of large bowel MC, and 7 cases of complex MC, involving omental bursa, spleen, and retroperitoneal structures like pancreas, kidneys, and major blood vessels [renal vessels, inferior vena cava, and superior mesenteric vessels]). OC was found in 12 cases (25.6%): cyst of the greater omentum in 11 and of the lesser omentum in 1. Mean size of the ALC was 9.5±5.5 cm (range, 3.4–30 cm).

The mean number of laparoscopic ports used was 2.6. LS was carried out using a single port in 9 cases (19.1%), two ports in 7 (14.9%), three ports in 26 (55.3%), and four ports in 5 cases (10.6%). Laparoscopic cyst excision was performed in 36 cases (76.6%) versus laparoscopy-assisted bowel resection en bloc with the cyst in 8 cases (17.0%). In 3 patients (6.4%), LS was converted to open surgery: 1 case of bleeding OC (LS was used for exploration only, and laparotomy was indicated because of massive bleeding) and 2 cases of complex MC with dense adhesion of the cyst to the major retroperitoneal blood vessels.

Mean operative time was 79±39 minutes (range, 30–165 minutes). There were no intra- or postoperative complications. No blood transfusion was needed except in 1 case with bleeding OC. Mean length of hospital stay after laparoscopic management was 3.8±1.6 days (range, 1–9 days).

Comparing LS between the OC and the MC groups, there were no significant differences regarding cyst size, mean number of ports used, or conversion rate (P>.05). However, mean operative time and postoperative stay were significantly shorter in the OC group in comparison with the MC group (60 minutes and 2.7 days versus 85 minutes and 4.1 days, respectively; P<.05).

The results of pathologic investigation showed benign cystic lymphangioma in all cases. For the follow-up period of 1 month to 4 years (median, 12 months), 1 patient (2.1%) had a recurrence 3 months after excision of a complex MC. All other patients remained in good health.

Discussion

The number of reports on management of ALC by LS in children and in the patient general population as well has been quite limited, and most of them have been anecdotal cases or small series.^6–13 According to our knowledge, this is the largest series of pediatric patients with ALC treated by LS reported to date.

Clinical presentations of ALC in children are nonspecific, and the most common symptoms are moderate abdominal pain and abdominal distention.^1–3,5,11 However, one must pay attention to the fact that some patients may have symptoms of acute abdomen due to bleeding or infection of ALC as seen in our study and in other reports.^1–3,11 Diagnosis of ALC is based mainly on imaging studies, especially ultrasound and CT.^1,3,4,14 Ultrasound has been reported as the most efficacious diagnostic modality by some authors.^3,4 According to our experience, although ultrasound could make the diagnosis of ALC in most cases, CT can define better the relations of the cyst with surrounding structure, especially major blood vessels, and thus is essential for planning the operative procedure. In rare occasions, especially cases of very large or bleeding ALC, ultrasound and even CT could misdiagnosis ALC as ascites, as seen in our series and in other reports. ¹⁵ In such cases, LS should be indicated as both a diagnostic and a treatment method.

Our experience showed many cases of ALC in children could be managed via a single port, especially OC and mobile simple MC (types I and II according to Losanoff et al. ¹⁶ ). Therefore we recommend that LS for ALC should always begin with one umbilical trocar. A 10-mm camera with an engrafted 5-mm working channel would be very useful. In many cases, the wall of the cyst can be grasped and delivered out through the umbilical incision. The cyst is then opened, and aspiration of cystic fluid is performed outside the abdominal cavity. This technique will decrease maximally the cystic volume, and thus the cyst can be delivered out of the abdomen through the umbilical incision (with or without minimal enlargement) and be excised (with or without bowel resection) extracorporally. In case this technique is not feasible, the cyst can be excised intraabdominally using two or more ports.

The results of this series show that LS for ALC in children is highly feasible as our rate of conversion was only 6.4%. This is much lower than the conversion rate of 3 of 9 reported by de Lagausie et al. ¹¹ This procedure is also safe as there were no perioperative complications or mortality. Adhesive intestinal obstruction after surgical management of ALC has been reported,^2,11 but in our series no case of postoperative intestinal obstruction was noted. LS for ALC in children has proven effective because only one recurrence of a complex MC (2.1%) was recorded in our follow-up. In a relatively large series of pediatric ALC, the recurrent rate of 9.5% after open surgery has been documented. ²

Because of the advantages of minimally invasive surgery and the results of this study and others,^11–13 we recommend that LS should be indicated for most ALC in children. The size of ALC does not matter because the cystic fluid can be aspirated, thus decreasing the cystic volume and creating better working space for the surgeon. According to our experience, there is almost no difficulty in performing laparoscopic resection of OC and simple MC (types I and II ¹⁶ ). In cases of complex MC (types III and IV ¹⁶ ) involving major retroperitoneal blood vessels, this procedure is much more delicate and should be carried out by experienced laparoscopic surgeons. Two of 7 such cases of complex MC in our series had to be converted. Therefore, a complex MC with intimate relations to major blood vessels—renal veins and arteries, superior mesenteric vessels, inferior vena cava, abdominal aorta, etc.—suggests a higher probability of conversion, and the choice of LS for its management should be considered carefully.

In summary, laparoscopic management is safe, feasible, and effective and should be the treatment of choice for most cases of ALC in children.