2533 Primary Mesenteric Lieomyosarcoma: A Rare Case Report

Abstract

INTRODUCTION: Sarcomas are a rare, heterogeneous group of neoplasms with varied histolopathological presentation, that share a common mesenchymal cell line origin. Soft tissue sarcomas tend to grow along tissue planes and can compress surrounding tissue, leading to the formation of pseudocapsules and finger-like projections that can infiltrate into adjacent tissue. Despite this, sarcomas rarely metastasize to regional lymph nodes. Sarcomas in the gastrointestinal tract encompass both gastrointestinal stromal tumors (GISTs) and leiomyosarcomas, which are rare neoplasms arising from smooth muscle cells and commonly misdiagnosed at GISTs. Mesenteric leiomyosarcomas usually present as a gradually enlarging, painless abdominal mass with associated symptoms usually arising from compression by the tumor. CASE DESCRIPTION/METHODS: A 68-year-old African-American female with history of hypertension, diabetes mellitus, and latent tuberculosis presented with decreased oral intake secondary to nausea, vomiting, and diarrhea for 2 days and unintentional 10-pound weight loss over a 2-month period. Physical examination revealed right upper quadrant tenderness. Computed tomography (CT) with IV contrast of the chest, abdomen, and pelvis showed a large right-sided solid mesenteric tumor causing extrinsic compression of the proximal and mid-portion of the right ureter with prominent right-sided hydronephrosis. CT guided biopsy revealed a smooth muscle neoplasm concerning for leiomyosarcoma with uncertain malignant potential. A right-sided ureteric stent was inserted to relieve extrinsic compression. An explorative laparotomy showed the tumor to be encasing the right ureter. Excision of the tumor along with right mid ureter was done with restoration of ureteric continuity via ureteroureteral anastomosis. DISCUSSION: Mesenteric leiomyosarcomas are rare and aggressive soft tissue tumors most commonly arising in the ileum. Biopsy is not recommended for local resectable tumors; however, it should be considered if metastatic disease is suspected or if preoperative imatinib is being considered prior to resection in the setting of a large locally advanced lesion. Treatment options depend on invasion of adjacent structures, including either local or en bloc resection. However, no nodal dissection is needed due to the rarity of nodal metastases.