[Two cases of endometrial stromal sarcoma (ESS) in which survival was prolonged by administration of MPA].

Endometrial stromal sarcoma (ESS) is very rare. It accounts for 0.5% of all uterine corpus malignant tumors and 10% of all malignant non-epithelial tumors. MPA is one effective hormonal treatment for ESS. We describe two cases in which patients with metastatic low-grade ESS lesions had prolonged survival with MPA therapy. Case 1 was a 50-year-old woman with a low-grade uterine endometrial stromal tumor who had been operated on at another hospital. She had been followed for three years. She had pelvis metastases with infiltration into the bladder, and pulmonary metastases. She had an incomplete response to chemotherapy. We initiated MPA therapy, which resulted in significant improvement in her metastatic lesions. Case 2 was a 58-year-old woman with stage Ic low-grade ESS who presented with abnormal uterine bleeding. Following surgery (TAH+BSO), MPA therapy was initiated and she had no recurrence. After 1 year and 7 months, she discontinued the MPA because it worsened her articular rheumatism. Her cancer recurred with pelvic and paraaortic lymph node metastasis. She was treated with chemotherapy, MPA and radiotherapy. Her metastases improved, and the patient has continued to survive on MPA therapy alone. These cases suggest that MPA might be an effective hormonal therapy for patients with low-grade ESS.