Synovial osteochondromatosis in a 14-year-old boy with a history of Legg-Calve-Perthes disease.

We describe a case of a 14-year-old boy with a history of Legg–Calve–Perthes disease diagnosed at the age of 6 years and development of synovial osteochondromatosis of the same hip joint 7 years later. Synovial osteochondromatosis is very rare in children, and to the best of our knowledge, only a single case of Legg–Calve–Perthes disease and secondary synovial osteochondromatosis was described in the literature in a 35-year-old male, making this the first reported case of Legg–Calve–Perthes disease with development of synovial osteochondromatosis in a pediatric patient.