Synchronous primary mammary osteosarcoma and invasive breast cancer. A case report - Pathohistological and immunohistochemical analysis.

Primary osteogenic sarcoma of the breast is a rare neoplasm, diagnosed mainly by pathohistological and immunohistochemical analysis. We hereby present a case of primary osteogenic sarcoma in the right breast of a 62-year-old woman with synchronous appearance of an invasive ductal carcinoma. Clinical findings are manifested with two separate painless formations 2.5 cm/2 cm and 1.5 cm/1 cm in size, located on the border of the upper and lower lateral quadrant of the right breast. No axillary lymphadenopathy was diagnosed. The pathohistological and immunohistochemistry findings of both tumors revealed a synchronous manifestation of two distinct neoplasms - epithelial and non-epithelial. Multimodality treatment consisted of Patey's radical mastectomy; 3 cycles of adjuvant chemotherapy; postoperative 50 Gy radiotherapy to the chest wall followed by additional 3 cycles of chemotherapy and anti-estrogen hormonotherapy. Due to the rarity of osteogenic mammary sarcoma, even more so in a combination with epithelial breast tumors, its clinical features are unclear and optimal treatment remains controversial. Considering the poor prognosis of the combination of both malignomas, we discuss a number of diagnostic and therapeutic issues.