Spontaneous Versus Morcellator‐related Benign Metastasizing Leiomyoma—a Retrospective Study

Objective To compare characteristics, disease course, and prognosis of spontaneous versus iatrogenic benign metastasizing leiomyoma (BML). Methods A retrospective cohort study comparing iatrogenic and spontaneous BML. Results Twenty cases were included, 12 (60%) spontaneous and 8 (40.0%) iatrogenic with a median follow up of 3.4 years. The rate of asymptomatic presentation did not differ between study groups (P = 0.157). When symptoms occurred, dyspnea was more common in the spontaneous group (66.6% vs 0%, P = 0.023) and self-palpation was more common in the iatrogenic group (57.1% vs 0%, P = 0.023). Intravascular masses were more common in the spontaneous group (66.6% vs 0%, P = 0.029). Rate of BML located in abdominal/pelvic cavity was higher in the iatrogenic group (100.0% vs 41.6%, P = 0.014). Of the 12 women in the spontaneous group, 50% had recurrent disease following surgical resection or unresectable lesions surgical resection was successfully attempted in seven of the eight (87.5%) women in the iatrogenic group, with no residual/recurrent disease. None of the patients died of her disease. Conclusion Spontaneous and iatrogenic BML can probably be regarded as two separate etiologies of the same pathologic phenomenon, usually with favorable prognosis. However, spontaneous BML may have a less favorable course.