A 66-year-old female presented with a several month history of a painful lesion on her sole that had been treated by multiple specialties, including orthopedics and podiatry, as a corn and as a wart without success.
A biopsy confirmed the diagnosis of a rare and benign condition called osteoma cutis. Strictly defined, osteoma cutis refers to the presence of bone within the skin in the absence of a preexisting or associated lesion. Secondary types of cutaneous ossification can occur in reaction to inflammatory, traumatic, and neoplastic processes — trauma being the most likely cause in this case. Simple excision is curative.
Differential diagnosis: The other options are all reasonable and biopsy is warranted if a presumed diagnosis does not respond to appropriate treatment.