Leiomyoma of the uterus showing skeletal muscle differentiation: A case report

A case of uterine leiomyoma with skeletal muscle differentiation is described. The patient is a 40-year-old woman who underwent abdominal hysterectomy and left salpingo-oophorectomy for fibroids, Evidence of skeletal muscle differentiation was evident at light and electron microscopy in one out of three "ordinary" leiomyomas, This was also shown by positive immunoreactions with antiskeletal muscle actin and myoglobin antisera, To our knowledge, this is the second case reported of the occurrence of skeletal muscle differentiation within a uterine leiomyoma and highlights the divergent differentiating potential of smooth muscle cells. HUM PATHOL 30:356-359. Copyright (C) 1999 by W.B. Saunders Company.