Pelvic intravascular leiomyomatosis associated with benign pulmonary metastasizing leiomyoma: clinicopathologic, clonality, and copy number variance analysis.

Benign metastasizing leiomyoma and intravascular leiomyomatosis are both rare smooth-muscle proliferations that of special interest due to their quasi-malignant behaviors. To elucidate the pathogenesis of these lesions, we checked the surgical samples from a 43-year-old female presenting multiple pulmonary and tricuspid valve lesions after a history of hysterectomy. Histopathological studies confirmed pelvic intravascular leiomyomatosis in the hysterectomy sections and the pulmonary nodules were proved to be benign metastasizing leiomyoma with strong positivity of estrogen as well as progesterone receptors. Clonality and copy number variance analysis, which were performed on pulmonary and uterine tumors, showed an identical X-chromosome inactivation pattern and a balanced karyotype respectively. Sequential occurrence of benign metastasizing leiomyoma and intravascular leiomyomatosis in same patient implied they were histogenetically related and our molecular genetic proofs further suggested that benign metastasizing leiomyoma is a unicentric, benign metastasizing process arising from initial intravascular leiomyomatosis.