Rare localizations of bone sarcoidosis: two case reports and review of the literature.

Sarcoidosis is a multisystem disease of unknown origin. Granulomatous bone involvement has an overall incidence of 1-13%. This incidence is probably underestimated in certain patient series because bone involvement is often asymptomatic. The small bones of hands and feet are the most common localizations, while skull, knee, rib, pelvic and sternal localizations are rarely reported. Here we describe some interesting cases of chronic sarcoidosis with unusual bone localizations observed at our regional referral centre for sarcoidosis. We also review the literature to underline the complexity of the disease, the problem of differential diagnosis with respect to malignancies and the need for appropriate and effective therapy of this rare localization.