Sarcoidosis is a systemic disorder characterized by non-necrotizing granulomatous inflammation, with varying degrees of concomitant fibrosis. It predominantly affects the lungs, eyes, and skin. A transmissible cause has long been suspected based on epidemiologic studies, transmission via organ transplantation.
The clinical presentation of sarcoidosis is highly variable. Involvement of the lungs or intrathoracic lymph nodes becomes clinically evident in 90% of symptomatic patients during their disease and up to 30% have spontaneous remission
Recent epidemiological data show a cumulative annual incidence rate of 1.36 per 100,000 inhabitants. The most relevant clinical aspects are the high incidence of Löfgren syndrome (48% of the cases), and the low percentage of cases diagnosed by routine chest X-ray (9%). The overall prognosis of sarcoidosis in Spain is good.