[Osteoarticular sarcoidosis]

Sarcoidosis (S) is a systemic disease affecting above all lymph nodes and lung tissue. Skeletal involvement is reported to occur in 14% of patients, the most common manifestations is cystoid osteitis, an asymptomatic lesion localized to the small bones of hand and feet. Lytic lesions are rare and usually accompanied by visceral involvement, the lesions may be detected in vertebral bodies and in long bones, pelvis and scapulae. MRI may be a good diagnostic tool, but open biopsy is often necessary. Joints are involved in about 89% of patients with acute sarcoidosis. Arthritis is localized more frequently to knees and ankles, is polyarticular, a little painful, migratory and transient, often accompanied by erythema nodosum. Clinical manifestations disappear in a few weeks, chronic and erosive disease is rare and always associated with systemic involvement. In these patients it may be useful to perform gallium citrate 67 scintigram and evaluation of serum ACE. Synovial biopsy lacks of specificity and sensibility, and in some cases it is necessary to perform open biopsy. S is a disease that may spontaneously regress and therapy may be unnecessary. In some cases, methotrexate may be useful in addition to prednisone. Chloroquine and hydroxychloroquine are effective in cases of skeletal involvement.