How would you treat this lesion?

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.

How would you treat this lesion?

A.Plantar wart
B. Eccrine poroma
C. Osteoma cutis
D. Amelanotic melanoma
E. Intractable plantar keratoses 

(Answer and discussion on next page)

Answer: Osteoma cutis

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.