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

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