Successful treatment of mast cell sarcoma of the uterus with imatinib.

Mast cell sarcoma is a rare disease characterized by localized, but destructive and rapid, growth of the tumor, high risk of distant metastasis, possibility of a leukemic phase, and poor prognosis. We report successful treatment of uterine mast cell sarcoma with imatinib in a 39-year-old woman who presented with abdominal distention and massive ascites. Routine treatment, such as combined chemotherapy, had little effect. We administered imatinib to the patient and achieved a good response in the absence of c-kit mutation, BCR/ABL, and FIP1L1-PDGFRα. Our results indicate that imatinib is of potential use in the treatment of mast cell sarcoma.