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Anomalous annular pancreas surrounding the superior mesenteric vessel

Between 1992 and 2007, six cases of cystic retroperitoneal lymphangioma have been operated on our institution, three males and three females, with a mean age of 39.5 years (range 16–73). The tumour showed up an abdominal mass in four patients, abdominal pain in one and abdominal distention and bowel obstruction in one. Two patients were symptom-free; the tumour was an incidental finding of an imaging test undertaken for other reason. Laboratory data were normal in all the patients. Ultrasonography (US) showed only cystic masses in both cases performed, computerized tomography (CT) scan revealed heterogeneous lesions and magnetic resonance (MR) demonstrated retroperitoneal masses without infiltration of organs in proximity; a diagnosis of lymphangioma was suggested in two cases. Intraoperative findings were soft, thin-walled, white–yellow, well-delimitated masses with chylous content (Fig. 1). The lesions were completely excised in all cases. In one patient, a jejunal loop resection was necessary because of an extension of the tumour into the mesenterium. Recovery of all the patients was uneventful. After a median follow-up of 96 months, all of the patients remain symptom-free and without evidence of recurrence. Lymphangiomas are hamartomatous congenital malformations of the lymphatic system. Around 50% are present at birth and grow slowly along the time. Cystic lymphangioma, also called cystic hygroma, is a variant of lymphangioma whose aetiology is uncertain. Cystic lymphangiomas can occur in any location in which lymphatics are normally found, but most of them are located in the head and neck (75%) and the axillary region (20%). Retroperitoneal lymphangiomas account for nearly 1% of all lymphangiomas, with less than 200 cases reported in literature. Intra-abdominal cystic lymphangiomas can arise from greater omentum, mesentery or retroperitoneum. Most cases are asymptomatic, such as two of our cases. When symptomatic, abdominal pain is the most frequent symptom. Bowel obstruction may appear secondary to tumoural compression of the bowel loops. Bleeding or infection of the cyst may cause an acute abdomen. Preoperative diagnosis of retroperitoneal lymphangiomas is rare before surgery. Ultrasonography may identify their cystic nature. CT scan and MR inform about size, extension and relationship with other organs. The diagnosis of lymphangioma is one of many potential differentials (benign and malignant) for a cystic mass arising in the retroperitoneum. Treatment consists of complete excision of the lesion. The outcome of resected retroperitoneal lymphangiomas is excellent, when incomplete resections, recurrence is feasible.