en Adults Hematology & Oncology Adults Hematology & Oncology گزارش مورد Case report Gastrointestinal Stromal Tumor (GIST) is the most common mesenchymal tumor of the gastrointestinal tract and most commonly affects the stomach, while fibromatosis is a rare locally aggressive fibrous tissue neoplasm. There have been reports of GIST and fibromatosis occurring in same individual and in most of them fibromatosis occurs within the abdomen. In 75% of patients fibromatosis occurs after the diagnosis of GIST while in 20% it is seen synchronously. Here we report a case of axillary fibromatosis with synchronous GIST of the gastroesophageal junction in a 45-year-old male treated with surgery and now on adjuvant imatinib.  Gastrointestinal stromal tumor, Fibromatosis, Gastroesophageal junction 138 140 http://ijbc.ir/browse.php?a_code=A-10-388-3&slc_lang=en&sid=1 Sugeeth MT sugeethmt@ymail.com 10031947532846006070 10031947532846006070 Yes Department of Medical Oncology, Regional Cancer Centre, Trivandrum, India Geetha Narayanan geenarayanan@yahoo.com 10031947532846006069 10031947532846006069 No Department of Medical Oncology, Regional Cancer Centre, Trivandrum, India