Multinodular hydropic leiomyoma of the uterus with perinodular hydropic degeneration and extrauterine extension.

Multinodular hydropic leiomyoma (MHL) of the uterus is one of the rarest variants of uterine leiomyomas and can create some diagnostic problems. Only five cases have been reported previously. We describe an MHL with perinodular hydropic degeneration in a 48-year-old woman. Gross examination revealed a large and predominantly intramural, edematous multinodular uterine tumor and extrauterine, small grape-like nodules overlying the lateral surface of the uterine serosa. Histologically, the tumor was composed of extra-intrauterine benign, small smooth muscle nodules with perinodular hydropic degeneration, prominent intramural dissecting growth pattern, and satellite nodules closely resembling vascular invasion. Immunohistochemically, these cells stained for desmin, smooth muscle actin and vimentin. The patient had no evidence of disease for 18 months after hysterectomy. Multinodular hydropic leiomyoma is a clinically benign tumor and should not be confused with intravenous leiomyomatosis and some other unusual leiomyoma variants.