RESUMO
Florid reactive periostitis ossificans is a rare bone lesion usually occurring in the small, tubular bones of the hands and feet. This entity is a benign and aggressive periosteal reaction associated with soft tissue swelling that appears similar to a bone lesion that radiographically and clinically mimics an infectious or neoplastic process. Typically the lesions occurs in an adolescent or young adult and presents as a small area of painful swelling and erythema over the affected bone. The cause of florid reactive periostitis ossificans is not exactly known though many authors have postulated varied etiopathogenesis for the same condition. In this report, is a very rare and unusual example of this entity that has been observed in association with erythema nodosum leprosum (ENL) a type 2 lepra reaction in a Leprosy patient.