<prompt> True about Sarcoidosis is?Skin is the most common organ involvedPremalignant conditionNon-caseating granulomaMay be associated with hypocalcaemia  <response>: Ans. is c i.e., Non caseating granulomas Sarcoidosis Sarcoidosis is an immune system disorder characterized by the presence of non-caseating granulomas aggregate of tightly clustered epitheloid cells, often with langhans or forein body type giant cells. Central necrosis is unusual Granulomas most often appear in the lung or the lymph nodes -- Bilateral hilar lymphadenopathy or lung involvement is visible on chest radiograph in 90 of cases. Granulomas also contain:-A. Schaumann bodies - Laminated concretions composed of calcium and proteins.B. Asteroid bodies - Stellate inclusions within giant cells.Clinical features1. Lung and lymph nodes 95 Respiratory complaints including cough and dysnea are the most common presenting symptoms. Usually the infiltrate in sarcoidosis are predominantly an upper lobe process. There is bilateral hilar lymphadenopathy. Potato nodes are seen in sarcoidosis.2. Skin 24-43 Skin lesions include erythma nodosum, maculopapular lesion, subcutaneous nodules, hypo or hyperpigmentation, keloid formation and lupus pernio. Lupus pernio is involvement of bridge of nose, area beneath the eyes and cheek. It is diagnostic for a chronic form of sarcoidosis.3. Eye 12-29 Eye lesions include uveitis, retinitis, pars planitis and dry eye due to lacrimal gland involvement. Uveoparotid fever Heerfordt-Waldenstrome syndrome include classical triad of Uveitis, parotitisand 7th nerve palsy.4. Other organs involved These are salivary glands particulary parotid causing dry mouth, spleen splenomegaly, liver, heart and brain neurosarcoidosis. Granuloma in sarcoidosis can secrete 1-25 OH2 vitamin-D which causes hypercalcemia. 