Extra-pulmonary organ involvement depends upon epidemiological factors, the means used for diagnosis and biases in recruitment. The World Association of Sarcoidosis and Other Granulomatous Disorders (WASOG) Organ Assessment Instrument may be useful to identify clinical scenarios consistent with sarcoidosis organ involvement (1). Using very sensitive tests that are not required in most patients like 18F-fluorodeoxyglucose-positron emission tomography (^18FFDG-PET) may unveil unexpected latent localizations (2). While pulmonary involvement is observed in 80%–95% of cases, the presence of any extra-pulmonary organ involvement is observed in around 50%, meaning that extra-pulmonary involvement is rarely isolated (8%–20%) and most often associated with pulmonary sarcoidosis (3). Parasarcoidosis syndromes observed in up to 70% of patients may be responsible for persistent disabling symptoms. Skin and eye involvement and peripheral lymphadenopathy are most frequent, 20% each in a worldwide series (4) and slightly lower in a multicentre US study (Table 16.1) (3). Lymph node, eye, bone marrow and skin involvement are more frequent in Blacks than in Caucasians. Eye and neurologic involvement are more frequent in women than men. Hypercalcaemia is more frequent in Caucasian males older than 40 (3). In Japan, uveitis and cardiac involvement are far more prevalent than elsewhere and muscle involvement is more common in females (5). Erythema nodosum is most often observed in females while bilateral ankle arthritis without skin lesions is more frequent in males (6). Erythema nodosum is very frequent in the United Kingdom and northern Europe populations while it is moderately frequent in Blacks and in Japanese (5,7). In children, liver, spleen and eye involvement and fever and weight loss are frequent (8,9). In elder patients, eye and specific skin lesions are unexpectedly frequent (10).