Metastizing low-grade clear cell leiomyosarcoma of the uterus

An unusual case of uterine clear cell tumor is reported in a 56-year-old woman. The neoplasm was identified as a peculiar low-grade leiomyosarcoma, composed mainly of watery, clear large cells with round, fairly regular nuclei. No appreciable pleomorphism or high mitotic activity was noted. There was no necrosis. The presence of occasional areas of transition between these cells and typical spindle leiomyosarcoma cells, together with the immunohistochemical results, allowed the recognition of a smooth muscle origin of this clear cell tumor. The patient was treated by hysterectomy. Six years later she developed an inguinal metastasis resembling an hibernoma, and then later developed a large retroperitoneal metastasis, which was composed entirely of clear cells and was distinguished from a liposarcoma by immunohistochemistry.