[Pulmonary sarcoidosis: Diagnostic challenges].

Sarcoidosis is a multisystemic granulomatosis of unknown cause that predominantly affects the lung and the lymphatic system, especially intrathoracic. The diagnosis relies on the association of a compatible clinical and radiological presentation, the presence of characteristic histopathological lesions (non-necrotizing epithelioid granuloma with giant cells) and the exclusion of other potential causes of granuloma. A meticulous analysis of other clinical manifestations, histopathology and outcome is necessary, particularly in cases with atypical pulmonary presentation (predominant ground glass opacity, excavated consolidation or masses, honeycombing, pleural involvement, or necrotizing sarcoidosis). Severe complications of the pulmonary disease include stage IV sarcoidosis, pulmonary hypertension, bronchial stenosis and pulmonary aspergillosis. In-depth knowledge of pulmonary sarcoidosis is required to ensure the diagnosis of this non-rare disorder of multiple presentation, to identify potentially severe cases and to guide therapeutic decision.