Response of recurrent uterine high-grade malignant mixed müllerian tumor to letrozole

Uterine malignant mixed müllerian tumor (MMMT) is a rare malignancy occurring most often in postmenopausal women. Despite the use of multimodality treatments including surgery, chemotherapy, and radiotherapy, prognosis is still poor in most cases. We report the case of a 69-year-old woman with recurrent metastatic high-grade MMMT that responded to letrozole, an aromatase inhibitor. At the initial diagnosis of high-grade uterine MMMT in February 2001, the patient underwent total abdominal hysterectomy, bilateral salpingo-oophorectomy, and postoperative pelvic radiotherapy. Two years later, an asymptomatic retroperitoneal mass was discovered on surveillance abdominal computed tomography scanning. The 3.5- × 3.0-cm mass was considered inoperable owing to its location near the aorta at the level of the renal vessels. The patient declined radiation or chemotherapy. Treatment with letrozole was begun at 2.5 mg daily. Serial computed tomography scans demonstrated marked tumor shrinkage; after 11 months of letrozole therapy, the tumor had shrunk to less than 25% of its original volume. Further study of letrozole for high-grade uterine MMMT is warranted.