Breast lump as the initial presentation of metastatic uterine leiomyosarcoma: a case report and comprehensive literature review

Abstract

Uterine leiomyosarcoma (uLMS) is a rare but aggressive cancer with a high metastatic potential and an unfavo-rable prognosis. A 54-year-old woman with a history of uterine fibroids clinically presented with a painless, palpa-ble left breast mass measuring 20 mm. A core biopsy of the breast mass demonstrated a cellular spindle cell neo-plasm (a potentially malignant smooth muscle neoplasm; B4). A wide local breast-mass excision was performed, re-vealing grade-2 leiomyosarcoma. A re-review of the uterine fibroids revealed that the largest one (200 x 130 mm), initially diagnosed as symplastic leiomyoma, was morpho-logically identical to the breast lesion. Additional diagnostic work-up revealed multiple liver and pulmonary metastases with a suspected metastatic sclerotic lesion in the L3 projection. The patient was subsequently treated with chemotherapy protocol for metastatic uLMS. The latest fol-low-up in September 2023 confirmed stable disease. This case highlights the importance of considering unusual metastatic patterns when evaluating breast masses, par-ticularly in patients with a history of non-specific uterine conditions. Comprehensive diagnostic work-up, including imaging and histopathologic examinations, is crucial for an accurate diagnosis of uLMS and appropriate treatment se-lection. Further studies are needed to better understand the underlying mechanisms and optimal management strategies for metastatic uLMS.