[A Case of Omental Desmoid Tumor after a Small Bowel Resection for Gastrointestinal Stromal Tumor].

An intra-abdominaldesmoid tumor, especially omentaldesmoid tumor, is rare. Here, we report a case of omentaldesmoid tumor after a smallbowelresection for gastrointestinalstromaltumor (GIST). A 73-year-old man underwent a partial resection of smallbowelfor GIST. He received adjuvant therapy with imatinib due to high risk of recurrence. After 2.5 years of treatment, a follow-up CT showed a 15mm nodule in the omentum near the splenic flexure. We considered the possibility of recurrence and imatinib failure, and laparoscopic tumor resection was performed for differential diagnosis. Immunohistochemicalstaining showed negative for c-kit, CD34, desmin, and S100. However, it was diagnosed as desmoid tumor because of positive b-catenin. Intra-abdominal desmoid tumor should be a differential diagnosis for a new single lesion in patients with GIST.