Pulmonary benign metastasizing leiomyoma following hysterectomy: a clinicopathologic correlation

Benign metastasizing leiomyoma is a rare condition with fewer than eighty (80) reported cases in the literature. We describe the clinical and pathologic findings in a 49-year-old woman who had undergone hysterectomy 15 years before presentation was referred to evaluate for pulmonary metastases with typical radiologic findings of bilateral multiple pulmonary nodules. Wedge biopsy of the lesion showed characteristic histologic findings of cytologically bland smooth muscle cells with scattered entrapped benign bronchiolar elements. Immunohistochemistry was positive only in smooth muscle cells for desmin, estrogen, and progesterone receptors. The clinical and histologic differential diagnosis and the importance of accurate diagnosis and prognostic significance are emphasized.