According to the Subcommittee on Classification and Definition of Sarcoidosis, it is a multisystem granulomatous disorder of unknown etiology. It most commonly affects young adults and presents most frequently with bilateral hilar adenopathy, pulmonary infiltrates, and skin or eye lesions. The diagnosis is established when clinical findings and appropriate x-ray findings are supported by tissue biopsy specimens in which noncaseating epithelioid cell granulomas are found. Immunologic features of the disease include depression of delayed hypersensitivity reactions, suggestive of impaired cell mediated immunity, and increased or abnormal immunoglobulin levels. Hypercalciuria may occur, with or without hypercalcemia. The course and prognosis of the disease correlate with the mode of onset. An acute onset in the presence of erythema nodosum indicates a self-limited course with spontaneous resolution, whereas an insidious onset may be followed by a relentless course. Corticosteroids are useful when therapy is required, as well as to suppress inflammation and the occurrence of granulomatous changes.