Dedifferentiated Liposarcoma of the Small Intestine Mesenteric Compartment Co-existing with Descending Colon Cancer

Abstract

A case of liposarcoma arising from the small intestinal mesentery that co-existed with descending colon cancer is reported. The patient was a 48-year-old man. Abdominal contrast-enhanced computed tomography (CT) was performed to investigate stool-related symptoms. In addition to descending colon cancer, a solid tumor with a strong contrast effect in the mesentery was found. Laparoscopy-assisted descending colectomy and small intestinal mesenteric tumor resection were performed to make a histological diagnosis. The tumor was elevated on the surface of the small intestinal mesentery, with a smooth, elastic, hard surface and yellowish-white and reddish-white areas. Histopathological examination showed polygonal to spindle-shaped cells against a background of fibrous tissue and edematous stroma. Atypical cells, including lipoblasts, were found in the surrounding fat-like tissue, and many of the atypical cells were positive for MDM2, CDK4, p16, and CD34, and the tumor was diagnosed as dedifferentiated liposarcoma. Magnetic resonance imaging performed 676 days after surgery suggested local recurrence, and a partial small intestinal resection was performed. Then, well-differentiated liposarcoma components were observed up to the mesenteric resection margin, and progression of the sarcoma to the retroperitoneum was suspected. Although two recurrences were observed after that, the patient has survived for 90 months.