Extrapulmonary lymphangioleiomyoma presenting as a mesenteric cystic mass

Lymphangioleiomyoma (LAM) is a rare benign tumor characterized by a disorganized smooth muscle cell proliferation within the walls of pulmonary, mediastinal, and retroperitoneal lymphatic vessels. The mesenteric LAM is a quite unusual presentation. A 47-year-old woman was admitted to our hospital with a 7-year history of abdominal mass. A computed tomography showed a well marginated mass with soft tissue attenuation. Laparoscopic excision was performed. The specimen revealed a well circumscribed dark cystic mass. The cut surface showed a thin walled cystic tumor with haphazardly distributed trabeculated septa. Microscopically, the tumor showed variable sized ectatic spaces lined by flattened endothelial cells and surrounded by epithelioid or spindle-shaped cells. The lining cells were positive for D2-40, CD31, and CD34. The surrounding cells were positive for alpha-smooth muscle actin and human melanoma black-45. The final diagnosis was a solitary LAM arising in the mesentery. The patient showed an uneventful postoperative course for 10 months.