Fatal venous thrombembolism complicating imatinib therapy in a patient with metastatic gastrointestinal stromal tumor.

Imatinib, a tyrosine kinase inhibitor, is currently the therapy of choice for gastrointestinal stromal tumor (GIST). The toxic effects of imatinib treatment are usually mild, and serious adverse events are rare. We report here the case of a patient with peritoneal metastases of GIST involving the pelvis treated by imatinib. Abdominal pain deteriorated early in the course of the therapy along with the enlargement of the tumors. The patient died suddenly, and the autopsy revealed pulmonary embolism originating from the deep vein thrombosis caused by the compression of common iliac vein by the tumor. The possibility of deep vein thrombosis caused by the compression of the veins by necrotic tumor should be considered in patients with abdominal or pelvic metastases of GIST, including patients treated with imatinib.