Although bone and cartilage have been described in a variety of extra-osseous nonneoplastic disease entities, references to such changes in the breast are rare. Willis1 details instances of bone formation in scars, skeletal muscle (myositis ossificans), arteries (atherosclerosis), cardiac valves (endocarditis), lungs (tuberculosis), lymph glands (tuberculosis), chronic salpingitis, and pancreas' (fat necrosis), as well as rare examples in skin, meninges, eye, thyroid, and the adrenal. It is significant that this study does not include any instances of involvement of the human breast. Review of the literature has failed to disclose any reported cases of ossification of the breasts related to chronic mastitis. In contrast to this, the occurrence of cartilage and bone have been described in association with both benign and malignant neoplasms of the breast.
The case described below is the first reported case of ossification of the breast associated with nonspecific chronic mastitis. It is also notable
France CJ, O'Connell JP. Osseous Metaplasia in the Human Mammary Gland. Arch Surg. 1970;100(3):238-239. doi:10.1001/archsurg.1970.01340210014005