Primary gastrointestinal stromal tumour of the ileum pre-operatively diagnosed as an abdominal abscess

The present case report described the acute presentation, diagnosis and management of a primary gastrointestinal stromal tumour (GIST) of the ileum. A male patient (age, 51 years) was admitted to Maggiore Hospital (Parma, Italy) due to presenting with fever, dysuria and lower abdominal pain. Ultrasonography and computed tomography showed a 7,5×5,5-cm pelvic mass containing air and purulent fluid indicative of an intraperitoneal abscess. The patient was subjected to diagnostic laparoscopy, which revealed a huge, soft cystic mass arising from the small bowel. The procedure was then converted to an open exploration through a midline incision. Ileal resection including a Meckel's diverticulum was performed. Macroscopic examination revealed that the cystic mass was filled with a large amount of pus, probably due to communication between the tumour mass and the small bowel lumen. In fact, the surgical specimen showed enteric leakage from the ileal mucosal ulcer into the tumour mass. Histopathology and immunohistochemistry of the abscess wall identified a spindle-cell mesenchymal-type, c-KIT-positive neoplasm. The post-operative course was uneventful and adjuvant imatinib mesylate was administered for 1 year. Follow-up by computed tomography demonstrated no tumour recurrence at 72 months after surgery.