LAUSR

A 64-year-old woman presented with a history of rheumatic heart disease, hysterectomy and left-side adnexectomy, high blood pressure, and hepatitis C virus. Routine ultrasound for hepatitis C virus revealed an abdominal cystic mass. Computed tomography (CT) showed a cyst measuring 13 × 11 cm, with fat density displacing and imprinting small intestine loops, without liquid level (Fig. 1, arrows). The CT diagnosis was appendicular mucocele, mesenteric cyst, or (less probably) ovarian carcinoma. Abdominal examination identified a mass effect in the right lower abdomen. Laboratory results, including hepatic and lipid profiles, were normal. The laparotomy revealed a cystic tumor of milky aspect dependent on the intestinal mesentery with a maximum diameter of 12 cm (Fig. 2). A 9-cm bowel resection was performed, including the mass. Histological and immunohistochemical study showed a vascular cyst, with a smooth internal surface, and partitions producing a multilocular appearance. The intestinal lumen did not present lesions. The cyst affected the intestinal wall, the serosa, muscularis propia, and submucosa, but not the mucosa. The immunohistochemical study was positive for D240 (lymphatic vessel marker) and CD31. The endothelial marker CD34 and mesothelial markers (mesothelin, MOC-31, calretinin and WT-1) were negative. The lesion was thus compatible with cystic lymphangioma. Analysis of the content of the cyst revealed triglycerides 5586 mg/dl, glucose 74 mg/dl, amylase 17 UI/ml, and proteins 125 g/L. The final histological diagnosis was chylous mesenteric cyst. In the follow-up at 86 months, no alterations have been observed.