Primary Appendiceal Gastrointestinal Stromal Tumor

Abstract Primary appendiceal gastrointestinal stromal tumor is extremely rare. To our knowledge, only 17 cases have been reported so far. Presented is a case of an 84-year-old woman who underwent elective laparoscopic right partial colectomy for an ileocecal mass found during colonoscopy. On gross examination, a 0.8-cm well-defined tan-white nodule was present in the distal portion of the appendix. Histology of the nodule showed proliferation of irregular fascicles of bland spindle cells, which stained positive for DOG1 (Ano1) and CD117 (KIT) and negative for S-100 and SMA. We report the incidental primary gastrointestinal stromal tumor of the appendix and discuss its biological behavior.