INTRODUCTION: Gastrointestinal stromal tumors are the commonest mesenchymal 
tumors of the gastrointestinal tract, the stomach and small intestine are the 
favored sites of occurrence. They rarely occur in the colon, rectum and 
esophagus. GIST is neoplasm of mesenchymal origin originating from precursors of 
the interstitial cells of cajal. The symptoms of gastrointestinal stromal tumor 
depend on the site and size of the tumor, and may include abdominal pain, 
gastrointestinal bleeding or signs of obstruction; small tumors may, however, be 
asymptomatic. Majority of the patients with gastrointestinal stromal tumor have 
bloody stools and abdominal pain as the commonest manifestation. We describe a 
young female with extra luminal colonic gastrointestinal stromal tumor 
presenting as mass abdomen.
CASE PRESENTATION: We describe 34-year-old female from north Indian state of 
Jammu and Kashmir who had presented with history of slowly increasing epigastric 
lump associated with abdominal discomfort of 4 months duration. She had no 
features of luminal obstruction. Her contrast enhanced computed tomography 
abdomen revealed a large extra-colonic mass in relation to transverse colon. The 
tumor was resected and histology was suggestive of gastrointestinal stromal 
tumor.
CONCLUSION: Extra luminal colonic gastrointestinal stromal tumors are very rare 
and can present as mass abdomen. Resection is the treatment of choice.