Primary osteosarcoma of breast - A clinical camouflage: Case report.

Abstract: Primary sarcoma of the breast is a rare clinical entity with an incidence of less than 1% among cases of breast cancer. Primary osteosarcoma of the breast is a very rare disease that shares clinical features similar to metaplastic breast carcinoma. A 57-year-old female Dravidian patient presented with a breast lump. A needle biopsy was suggestive of carcinoma. However, the mammogram was suggestive of dense calcification lesion, which is unusual in carcinoma. She underwent breast conservation surgery with sentinel lymph node biopsy; final histopathology was suggestive of osteosarcoma of the breast. After a follow-up of 18 months, the patient is healthy and disease-free. Primary breast osteosarcoma has to be considered as one of the differential diagnoses to metaplastic carcinoma and warrants a different treatment approach. Whenever there is discordance in clinical features, imaging, and histology, thorough evaluation with the mammogram, immunohistochemistry, and PET scan helps to resolve the issue.