Atypical decubital fibroplasia associated with bizarre parosteal osteochondromatous proliferation (Nora's reaction)

We describe recurring bizarre parosteal osteochondromatous proliferation (N ora's reaction) associated with atypical decubital fibroplasia in the regio n of the greater trochanter of the femur in a 52-year-old man. We hypothesi ze that these two recently introduced entities may represent two forms of t issue response to injury (ischemia) inducing proliferative reaction of bone and cartilage in the vicinity of periosteum, and necroses with hyperplasti c granulation tissue and myxoid stroma in the subcutaneous tissues.