Melorheostosis mimicking synovial osteochondromatosis.

Melorheostosis is an uncommon, sporadic, sclerosing bone lesion that may affect the adjacent soft tissues. It has been associated with many entities such as osteopoikilosis, soft tissue vascular malformations, bone and soft tissue tumors, nephrotic syndrome, segmental limb contractures, osteosarcoma, desmoid tumor, and mesenteric fibromatosis. Synovial osteochondromatosis is a benign neoplasia of the hyaline cartilage presenting as nodules in the subsynovial tissue of a joint or tendon sheath. The intra-articular extension of melorheostosis mimicking synovial osteochondromatosis has not been reported before. In this article, the authors describe an unusual case mimicking synovial chondromatosis arising as a result of melorheostosis and their characteristic imaging findings.