[Bizarre parosteal osteochondromatous proliferation (Nora's lesion): two cases]. / La lésion de Nora ou Bizarre Parosteal Osteochondromatous Proliferation: à propos de 2 cas

The lesion Nora described in 1983 as a bizarre parosteal osteochondromatous proliferation (BPOP) is a member of a group of osteocartilaginous surface lesions. BPOP is infrequent but new cases are regularly reported. We report two new cases with an unusual localization (ilion and distal humerus) and unusual size (9 cm for the iliac lesion). In light of these cases and reports in the literature, the main differential diagnoses of BPOP are exostosis and parosteal osteosarcoma.