Mesenteric fibromatosis is a rare type of desmoid tumor characterized by local aggressiveness and a tendency to relapse. In view of these characteristics it may be considered a low-grade fibrosarcoma. Camurati-Engelmann disease is a very rare form of bone dysplasia characterized by osteosclerosis of the diaphyses of the long bones. Here we describe the case of a male patient affected by these two rare diseases in association with chronic inflammatory intestinal disease.