Late presentation of metastatic smooth muscle neoplasm of the uterus with low malignant potential.

A 48-year-old woman underwent total abdominal hysterectomy with conservation of the ovaries and tubes. Histology showed a well-circumscribed smooth muscle tumor with foci of degeneration (including infarct-type necrosis) but no coagulative tumor cell necrosis and only mild focal cytological atypia. She presented, 24 years later with shortness of breath and abdominal distension and underwent bilateral salpingo-oophorectomy, appendectomy, omental biopsy and para-aortic lymph node sampling. Histology showed bilateral ovarian smooth muscle tumors with no coagulative tumor cell necrosis or significant cellular atypia. The cells were mitotically active. The tumors in both ovaries were most likely secondary to the previous uterine smooth muscle neoplasm. To our knowledge, this case is the first in the literature to describe a benign cellular leiomyoma that subsequently behaved as a smooth muscle tumor of uncertain malignant potential, which recurred 24 years after the initial diagnosis.