A Rare Case of Myxochondroid Metaplasia of the Plantar Foot.

We present a case of a 52-year-old male with a slowly enlarging, asymptomatic nodule on his heel diagnosed as myxochondroid metaplasia of the plantar foot. The incidence is rare, as this is only the second case reported since it was first discovered. It is a benign tumor believed to represent a reaction to chronic mechanical stress, presenting as a variably painful, skin-colored nodule on the plantar foot. Histologically, a subepidermal nodule comprised of spindled fibroblasts and cartilaginous elements is seen. It is histopathologically reminiscent of the nuchal fibrocartilaginous pseudotumor as well as the acquired equine digital cushion, two other reactive fibrocartilaginous growths in the neck and a horse's hoof, respectively. Excision is curative.