Breast sarcoma with unusual metastasis: case report and literature review

Introduction Undifferentiated spindle cell sarcomas (USCSs) of the breast are extremely rare, and their metastasis to the mandible and vertebrae is even rarer. This report presents a case of breast USCS metastasized into the mandible and vertebrae. Case presentation A 45-year-old woman presented with a rapidly growing, firm, non-tender left breast mass. Core biopsy confirmed high-grade USCS (Grade III). She underwent wide local excision with sentinel lymph node biopsy, which showed a 5.8 cm tumor (pT2N0) with high mitotic index, extensive necrosis, and negative margins. Nine months later, she developed lower lip numbness, and contrast-enhanced computed tomography revealed a mandibular lesion along the inferior alveolar nerve. Biopsy confirmed the lesion as metastatic sarcoma. Three weeks later, severe back pain led to magnetic resonance imaging detection of vertebral metastases (T12- L2), which were confirmed histologically. She was put on palliative chemotherapy, bisphosphonates, and neuropathic pain management, with stable disease at 4 months post-diagnosis of metastasis. Literature review Nine cases of primary and metastatic oral cancer were reviewed, of which seven cases were females. Pain and swelling were the most common symptoms. Among the five cases with metastasis, in four of them, the primary cancer originated from the breast. Treatments varied, including surgical approaches, chemotherapy, hormone therapy, and radiotherapy, and two patients died. Conclusion Breast USCS is a rare sarcoma that might metastasize to the mandible and vertebrae. Breast-wide local excision and radiotherapy may reduce the risk of local recurrence; however, distant metastasis may still occur.