[Organized pneumonia].

Organizing pneumonia is a condition first described in 1941. Its symptoms are nonspecific (fever, arthromyalgia, etc.), and its diagnosis relies primarily on histology, when this is not feasible, it is based on a combination of clinical, laboratory, and radiological findings, in the absence of a differential diagnosis particularly active infections. It is a rare condition that may be secondary to another condition or primary and referred to as cryptogenic. Numerous causes of organized pneumonia have been described: post-infectious, associated with connective tissue diseases, drug-induced, etc. It affects all age groups, with the idiopathic form predominantly occurring between the ages of 50 and 60. A non-contrast chest CT scan may be suggestive but remains nonspecific and must rule out infection. Bronchoalveolar lavage can help rule out active infectious causes and provide diagnostic clues; however, the gold standard remains histological examination, which reveals endoalveolar buds, an inflammatory infiltrate of the alveolar walls, and thickening of the alveolar walls. Treatment is usually based on corticosteroid therapy for the cryptogenic form but must be tailored to the underlying condition when the disease is secondary. The prognosis is generally favorable in the cryptogenic form and depends on the cause in the secondary form.