International Journal of Biomedical Research ISSN: 0976-9633 (Online) Journal DOI:10.7439/ijbr CODEN:IJBRFA Case Report A rare case of retroperitoneal leiomyosarcoma with gastrointestinal stromal tumour of rectum Shashirekha C.A * ., Nagaraj K.N., Vijay P Agrawal, Harendrakumar N Dept. of General Surgery, Sri Devaraj Urs Medical College, Tamaka, Kolar-563101, Karnataka, India *Correspondence Info: Dr. Shashirekha C.A Assistant Professor, Dept. of General Surgery, Sri Devaraj Urs Medical College, Tamaka, Kolar-563101, Karnataka, India E-mail- drca_shashirekha@yahoo.co.in 1. Case study A 45 year man presented to Surgery opd with chief complaints of rectal bleeding and constipation for 1 month. There was no history of pain and mass per rectum. There was a history of histopathological and immunohistochemistry proven retroperitoneal leiomyosarcoma (Figure 1) for which he was operated in tertiary center 8 months back. Colostomy was done and was closed after 3 months. He received 2 cycles of gemcitabine and docetaxel based chemotherapy. His physical exam was unremarkable other than a digital rectal exam which revealed a firm mass in the posterior rectal wall. Biopsy from the mass was taken. Histopathology revealed differential diagnosis for leiomyosarcoma and gastrointestinal stromal tumour (GIST). (Figure 2) Figure 1 - leiomyosarcoma with high cellularity, spindle-shaped stromal cells, and mitoses (H&E´200) IJBR (2013) 04 (05) www.ssjournals.com Abstract Leiomyosarcoma is a rare malignancy of smooth muscle. Leiomyosarcoma may arise from the retroperitoneum and present with nonspecific signs and symptoms. The most common presentation is abdominal pain. In the past gastrointestinal stromal tumour (GIST) were misdiagnosed as leiomyosarcoma. GISTs however have been shown to lack features of smooth muscle tumors on histopathology. They are often CD34 and CD 117 immunoreactive in contrast to leiomyosarcoma. We present a rare case of retroperitoneal leiomyosarcoma with gastrointestinal stromal tumour of rectum in the same patient. Keywords: Leiomyosarcoma, retroperitoneum, gastrointestinal stromal tumour