Hemorrhagic cellular leiomyomas ("apoplectic leiomyoma") of the uterus associated with pregnancy and oral contraceptives.

The clinical and pathological findings in 22 women with a distinctive hemorrhagic cellular (HC) leiomyoma of the uterus are described. Characterized by a dense cellularity accompanied by hemorrhage and edema, 17 occurred in women taking oral contraceptives, three occurred in pregnant women, and one was found in a woman 3 days postpartum. One woman, not pregnant or taking steroids, was using hydrochlorothiazide. Recognition of this special form of leiomyoma associated with the use of reproductive steroids is needed to avoid confusing it with leiomyosarcoma. The major differences with leiomyosarcoma are that HC leiomyomas are generally small, often multiple, and have discrete areas of hemorrhage and tearing artifact, but little or no atypia. Also, their mitotic activity is confined to a narrow zone adjacent to the hemorrhage.