Primary breast osteosarcoma: A case report and mini‑review of the literature

Primary breast osteosarcoma (PBO) is an exceedingly rare form of breast cancer. The present study reports the case of a 45‑year‑old female patient with PBO with atypical manifestations. The patient sought medical consultation due to a painful, slowly growing lump in her left breast for 2 months. Upon a physical examination, a palpable mass was noted in the left upper outer quadrant. The mass was ill‑defined, hard, tender and immobile. There was no axillary lymphadenopathy. A core needle biopsy from the mass indicated a breast fibroadenoma with focal inflammation and a giant cell reaction, while the axillary lymph nodes were benign. The patient underwent wide local excision of the left breast without axillary lymph node management. No adjuvant chemotherapy or radiotherapy was prescribed. The detailed pathogenesis of PBO is not yet fully understood. Different origins and predisposing factors have been proposed. Complete removal of the mass with clear margins seems to be the most effective medical intervention. The significance of adjuvant chemotherapy and radiation therapy is still a matter of debate. Due to its rarity, PBO can be challenging to diagnose pre‑operatively, necessitating a detailed histological examination of the resected specimen along with immunohistochemistry to reach an accurate diagnosis.