Apoplectic Leiomyomas: A Morphologic Analysis of 100 Cases Highlighting Unusual Features

Leiomyomas with apoplectic change related to progestational effect have not received much attention in the literature and in our experience frequently cause diagnostic difficulty. We reviewed 100 apoplectic leiomyomas to characterize their broad histologic spectrum. The tumors occurred over a wide age range (mean, 41 y), and although 2 patients were pregnant, in the vast majority the apoplectic changes were likely due to progestins administered to help control symptoms related to the leiomyomas. Leiomyomas were multiple in 77% of patients, averaged 6 cm, and frequently showed gross features of hemorrhage, necrosis, cyst formation, softening, or color different than the usual banal leiomyoma. Microscopic examination typically revealed multiple stellate to ovoid zones with a hypercellular periphery and central hemorrhage, necrosis, or hyalinization. The hypercellular areas were often dominated by cells with eosinophilic cytoplasm, pyknotic nuclei, and increased mitoses (up to 14/10 high-power fields), but most tumors showed no appreciable cytologic atypia in these regions. Edema was noted in 95%, a hyalinized and/or myxoid matrix in 92%, and cyst formation in 42%. Because of these unusual features, difficulty often arose in determining whether the tumors were benign, malignant, or of uncertain malignant potential. Recognition of their wide morphologic spectrum will enable classification in the benign category and avoid undue patient anxiety and potentially unnecessary aggressive management.