A Case of Leiomyosarcoma of the Sigmoidal Mesocolon which was Difficult to Diagnose

Abstract

Leiomyosarcomas of the mesocolon are rare and often very large when detected. However, these tumors are difficult to diagnose preoperatively and are often surgically resected. We report a case in which a patient with an abdominal mass, initially diagnosed as an inflammatory degenerative uterine fibroid, was later identified as a sigmoid leiomyosarcoma of the mesocolon. A 41-year-old female was referred to our hospital with abdominal pain, a high inflammatory response, and tumor growth. The patient had been previously diagnosed with pregnancy complicated by fibroids at another hospital. She delivered naturally, but her symptoms worsened, necessitating semi-emergency surgery. The tumor was found in the sigmoidal mesocolon and a sigmoid colon resection was performed. There was no infiltration into other organs ; therefore, complete resection was achieved. The histopathological diagnosis was leiomyosarcoma. Currently, after performing postoperative adjuvant chemotherapy, we are continuing careful follow-up. The patient has survived without recurrence nine months after surgery.