International Surgery Journal | February 2021 | Vol 8 | Issue 2 Page 754 International Surgery Journal Singh V et al. Int Surg J. 2021 Feb;8(2):754-756 http://www.ijsurgery.com pISSN 2349-3305 | eISSN 2349-2902 Case Report Pleomorphic leiomyosarcoma of colonic mesentery: an unusual cause of lower GI bleed - case report and literature review Vandana Singh*, Lalit Aggarwal, Priya Hazrah, Shadan Ali, Ashok Kumar, Anup Mohta INTRODUCTION Leiomyosarcoma is a malignant mesenchymal tumour originating from smooth muscle cells typically of uterine, gastrointestinal or soft tissue origin. Leiomyosarcomas arising from each site has unique clinical, radiological and histological features. 1 The underlying mechanism of development remain unclear. Leiomyosarcomas arise from smooth muscle of blood vessels in the mesentery. Majority of them arise from stomach and small intestine mesentery. However primary pleomorphic leiomyosarcoma of mesocolon with LGI bleeding are extremely rare. These tumours are highly aggressive and surgery is probably best option for treatment. Because of rarity of tumour, standard chemotherapy regimen is not yet established. CASE REPORT A 27-year-old gentlemen presented with complaints of pain in left upper abdomen for two months with a progressively increasing abdominal mass since one month, associated with complaints of anorexia, weight loss and chronic constipation. Single episode of massive rectal bleeding causing drop in haemoglobin level from 9 ABSTRACT Mesenteric masses are infrequent lesions ranging from benign cyst to aggressive malignancies and often present as diagnostic and therapeutic challenge. The mesentery is a frequent recipient of metastasis from the gastrointestinal tract, pancreas, and biliary cancers. Primary mesenteric tumours are relatively rare, mostly mesenchymal in origin and benign in nature. Examples include gastrointestinal stromal tumours and smooth muscle tumours. Pleomorphic leiomyosarcoma of mesocolon is extremely rare with a reported incidence of 1:350,000. So accurate preoperative diagnosis of mesenteric soft tissue tumours is generally difficult. It accounts for less than 1% of the malignant tumours found in colon. Leiomyosarcoma is a malignant tumour arising from smooth cell lineage. These tumours occur most commonly in middle aged individuals. We describe a case of pleomorphic leiomyosarcoma arising from the colonic mesentery in a 27-year-old male patient, with massive lower gastrointestinal bleed (LGI bleed) causing drop in haemoglobin level from 9 mg/dl to 6 mg/dl. Ultrasonography and CECT abdomen suggestive of (17.5×11.6×10.6) cm mass in left side upper abdomen in splenic hilar region. Left hemicolectomy with excision of mass with splenectomy and distal pancreatectomy done. The diagnosis was based on histopathological evaluation using immunohistochemistry (IHC). Histopathological report suggestive of pleomorphic leiomyosarcoma with SMA and vimentin positivity on immunohistochemistry but CD 34 and CD 117 were negative, differentiating it from GIST. Keywords: Leiomyosarcoma, Mesentery, Lower gastrointestinal bleed Department of General Surgery, Lady Hardinge Medical College, New Delhi, India Received: 02 November 2020 Revised: 15 January 2021 Accepted: 18 January 2021 *Correspondence: Dr. Vandana Singh, E-mail: vandana.chauhan51@gmail.com Copyright: © the author(s), publisher and licensee Medip Academy. This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License, which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. DOI: https://dx.doi.org/10.18203/2349-2902.isj20210399