Late-onset pulmonary benign metastasizing leiomyoma 3 decades after hysterectomy: A case report

Uterine leiomyomas are the most common benign tumors of the female reproductive tract. In rare cases, they may disseminate beyond the pelvis without malignant features, a condition known as benign metastasizing leiomyoma (BML). The lungs are the most frequent site of involvement, typically appearing years after hysterectomy. We report a 74-year-old woman with a history of hysterectomy at age 43 who underwent resection of a pelvic mass in 2022, which was diagnosed as a cellular leiomyoma. In 2025, surveillance imaging revealed a multilobulated pelvic mass and multiple bilateral solid pulmonary nodules, the largest measuring 9.5 mm, without mediastinal lymphadenopathy. The patient remained asymptomatic (ECOG 0). A multidisciplinary team opted for active surveillance, given the benign histology and the absence of clinical progression. This case highlights that benign metastasizing leiomyoma (BML) can present even several decades after uterine surgery, emphasizing the need to consider this diagnosis in women with a gynecological history who develop pulmonary nodules. It also underscores the central role of computed tomography in detecting both typical patterns of pulmonary dissemination and atypical findings such as potential intravascular extension. Finally, it illustrates that despite their benign histology, cellular leiomyomas may display unpredictable biological behavior, making multidisciplinary evaluation and careful radiological follow-up essential before pursuing more aggressive therapeutic approaches.