Pulmonary Benign Metastasizing Leiomyoma with Abdominal Wall and Pelvic Cavity Implantation: A Case Report and Literature Review.

Benign metastasizing leiomyoma (BML) is a rare condition characterized by extrauterine proliferation of benign smooth muscle cells. We present a rare instance of pulmonary BML with concurrent abdominal wall and pelvic implantation. A 47-year-old female presented with palpable abdominal wall nodules and pelvic lesions following a history of myomectomy and hysterectomy. Imaging revealed vascularized nodules in the abdominal wall, rectal mesentery, and bilateral lungs. Surgical excision of abdominal and pelvic nodules confirmed cellular leiomyoma. Post-oophorectomy, lung nodules initially regressed but subsequently progressed. Wedge resection confirmed pulmonary BML. Literature review highlights substantial heterogeneity in BML cases. Although many cases are associated with prior uterine surgery, cases without surgical history suggest that spontaneous dissemination may also occur. In the present case, the coexistence of pulmonary, abdominal wall, and pelvic lesions raises the possibility that hematogenous or lymphatic dissemination and iatrogenic implantation may have coexisted, although this hypothesis requires further molecular validation. Standardization in the definition and classification of BML may help improve diagnosis and management. Careful surgical handling, incision protection, and long-term follow-up are warranted in patients with recurrent or atypically behaving leiomyomas.