Primary Leiomyosarcoma of the Mesentery: A Case Report With Review of Literature.

Mesenteric leiomyosarcoma (LMS) is a rare gastrointestinal mesenchymal tumor. It was often misdiagnosed as a gastrointestinal stromal tumor (GIST) until the introduction of immunohistochemistry staining (IHC) in 1998. Currently, a positive IHC staining for smooth muscle markers represents the main diagnostic modality. Herein, we present a case of Mesenteric LMS in a 68-year-old woman, who presented with nausea, vomiting, and abdominal pain and was found to have a right-sided mesenteric tumor encasing the right ureter, with right hydroureteronephrosis. The patient underwent surgical removal of the tumor and IHC stains were compatible with LMS. She achieved remission until she developed recurrence 12 months after initial diagnosis and subsequently expired due to postoperative complications when re-resection was attempted. Typically, mesenteric LMS carries a poor prognosis with a propensity for hematogenous metastasis. In the absence of a standardized protocol for therapy, early surgical resection is the only known curative modality but with a high risk of recurrence.