Uncommon Presentation of a Rib Osteochondroma Misdiagnosed as a Breast Lesion: A Case Report

Osteochondromas are common benign bone tumors. Rarely, these lesions present on the ribs and can be concerning for a breast mass. This case discusses a healthy 21-year-old female with a firm, fixed, painful breast mass. Her initial ultrasound and 6-month follow-up ultrasound were both benign. The mass gradually increased in size with continued pain over 2 years. Almost two and a half years after presentation, the patient had an additional ultrasound and CT chest revealing a bony exostosis from the anterior aspect of the third rib. Excision was performed in a joint case with orthopedic oncology and plastic surgery, with pathology confirming the diagnosis of an osteochondroma.

It is important to consider alternative diagnoses, such as rib osteochondroma, in the differential diagnosis of firm, fixed breast masses in young, postpubescent females.