Abnormal growth of a pleomorphic leiomyosarcoma originating from the mesenteric vein associated with poor outcome after curative-intent resection: a case report

BACKGROUND: A leiomyosarcoma (LMS) is a rare tumor that mainly originates from the urinary tract and digestive system; however, non-visceral organ-derived patterns are rare. Herein, we report that a vessel-derived pleomorphic LMS (PLMS) originating from the mesenteric vein has a poor prognosis even after curative-intent surgery. CASE PRESENTATION: The patient was a 41-year-old woman with no relevant medical history. The patient presented with abdominal pain and an abnormal bulge on the left lower abdomen. Magnetic resonance imaging revealed a large tumor occupying the left abdomen. Enhanced computed tomography revealed a bulky tumor with a maximum size of 13 × 13 cm with impending rupture, and a small amount of ascites was detected around the tumor. As the tumor directly invaded the small intestine and descending colon, left hemicolectomy and partial resection of the small intestine were performed. The patient was discharged on postoperative day 10, without any complications. On histopathological analysis, the tumor was diagnosed as a vessel-derived LMS with a pleomorphic pattern. The patient died due to disseminated intravascular coagulation because generalized peritonitis was induced by the super-early recurrence of the tumor 2 months after the surgery. CONCLUSIONS: Regardless of curative-intent surgery for a vessel-derived PLMS, super-early local recurrence and distant metastasis were observed. A vessel-derived PLMS requires further investigation to determine its characteristics and therapeutic strategies to improve long-term prognosis.