[A case of multiple metastatic giant rectal GIST successfully treated with surgical intervention after administration of imatinib mesylate].

A 69-year-old man was admitted with difficulty in defecation and urination. CT showed a giant tumor connected with the rectum in the lower pelvic cavity, and also the presence of 4 smooth surfaced tumors, 3 of which were in the abdominal cavity, while the other one was in the left inguinal region. A core needle biopsy was performed in the left inguinal region indicated the presence of gastrointestinal stromal tumor (GIST), and we clinically diagnosed this case as having multiple metastatic rectal GISTs. The patient was treated with imatinib mesylate, and CT showed the size of the rectal GIST to have dramatically decreased, with only one metastatic tumor remaining in the abdominal cavity. Therefore, an abdominoperineal resection and metastasectomy were performed, and the tumors were completely excised. The patient is alive without recurrence at 18 months after surgery, while continuing to receive imatinib mesylate.