DOI: 10.36347/sjmcr.2015.v03i10.013

Pages: 971-974

Herein, we have reported unusual behavior of clinical presentation of malignant gastrointestinal stromal tumor (GIST). The aim of the present study was to differentiated leiomyosarcoma (LMS) and GIST with respect to clinical presentation and pathologic parameters. A 48-year-old man referred to our Clinic with complaint of abdominal pain and generalized lymphadenopathy. In abdominal CT scan, there were a prominent lesion in left lung and also a mass lesion in left lobe of liver. In immuno histology report, S100 and CD34 were negative but SMA and Desmin were positive. He was treated with chemotherapy for LMS but he didn’t respond to this treatment. C-Kit was evaluated in the first pathology sample and was positive. Therefore, he had GIST and after that he was treated only with imatinib 400 mg/day. Because similarity of morphological pathologic of LMS to GIST, type of metastasis, age, sex and markers such as S100, CD34, Desmin and SMA are not sufficient for distinguish between of GIST and LMS and also C-Kit must be checked in patients.