A Recurrent Case Report of Bizzarre Parosteal Osteochondromatous Proliferation (Nora Disease) and Literature Review

Bizarre parosteal osteochondromatous proliferation (BPOP), as defined by Nora and colleagues [1] in 1983 (also called Nora lesion), is a rare lesion. About 160 cases of BPOP have been presented in the literature until now. The lesion is an outgrowth from the cortical surface consisting of bone, cartilage and fibrous tissue. It usually affects the proximal and middle phalanges, and the metacarpal or metatarsal bones. The hands are 4 times more commonly affected than the feet [2]; however, lesions in the long bones, skull, maxilla and metatarsophalangeal sesamoid have been reported [3-5].