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.