Giant Mesothelial Inclusion Cyst

Abstract

A male in his 70's presented for evaluation of an inguinal hernia, complaining of constipation and intermittent bulging in the right inguinal area; however, on examination a protuberant mass was appreciated in the central lower abdomen. The patient was stable and had no prior knowledge of the mass. An air-filled, lobular structure of the sigmoid colon, 17 cm in greatest dimension was identified on CT. Imaging from six months prior showed typical diverticulosis of the sigmoid colon, but nothing consistent with the size of the current lower abdominal mass. The patient was taken for exploratory laparotomy, small bowel resection with primary anastomosis, Hartmann's procedure, partial cystectomy, and ureteral stent placement. Pathology showed a mesothelial inclusion cyst, also known as benign cystic mesothelioma. Such cysts have only ever been reported in literature up to 200 times, [1] and are more common in women, especially of reproductive age [1-6].