[Bizarre parosteal osteochondromatous proliferation (Nora's lesion). Two case reports]

Bizarre parosteal osteochondromatous proliferation, or Nora's tumor, is an uncommon lesion, involving mostly tubular bones of hands and feet, arising from the cortical surface. It must be distinguishable from chondrosarcoma, parosteal osteosarcoma and florid reactive periostitis. It is a benign lesion, characterized by a proliferation of chondroid, bony and fibrous tissues. The authors report two cases involving the hand. The diagnosis can be made thanks to imaging techniques and confirmed by histological examination. The treatment is surgical, namely complete excision but there is a high rate of local relapse.