“…The exact prevalence of primary or secondary SC is unknown, but a few representative case series showed 38 SC cases of all inhabitants (127 000) population in Spain and 20 cases were primary SC, 136 cases of loose bodies in joints over 7 years at Hospital for Special Surgery in New York and 10 cases were primary SC, 4 cases of 107 synovial biopsies over 12 years in Hong Kong,78 of 30 000 orthopedic patients over 32 years at Birmingham Hospital in the UK . Associated SC conditions such as trauma (72 cases) degenerative joint diseases (44 cases) metabolic joint diseases (4 cases) immune inflammatory (9 reported casesand present case) and other diseases (15 cases) were previously reported. AS, ankylosing spondylitis; FOP, fibrodysplasia ossificans progressive; LS, lumbar spondylolisthesis; OC, osteochondrom; OP, osteopoikilosis; PVNS, pigmented villonodular synovitis; RP, relapsing polychondritis…”