Low-grade fibromyxoid sarcoma of the sigmoid colon.

Low-grade fibromyxoid sarcoma (LGFMS) is a rare soft tissue tumor with a slight male predominance. The tumor has a tendency to arise from deep soft tissue of the trunk and lower extremities. Rare cases are reported to arise from the mediastinal and retroperitoneal areas. Its deceptively bland histologic appearance makes this tumor difficult to diagnose. Also, there are several histologic mimics that may hinder in its diagnosis. We report a case of low-grade fibromyxoid sarcoma from a 48-year-old woman, first documented herein to arise from the sigmoid. We also report the value of CD99, BCL2 and MUC4 stains in the diagnosis of this tumor.