Follicular bronchiolitis: A rare cause of persistent atelectasis in children.

Although atelectasis is common in children, its persistence or refractoriness to treatment should lead prompt evaluation to identify causal mechanism. We describe the case of a child presenting in first year of life with persistent left upper lobe atelectasis, recurrent wheezing and respiratory infections refractory to medical therapy, submitted to partial lobectomy when he was 3 years old age. Histopathological examination revealed follicular bronchiolitis. Systemic underlying diseases were excluded. Clinical improvement was initially achieved using inhaled corticosteroids, but oral therapy was needed due to clinical relapse, with favorable response. Follicular bronchiolitis, a rare pulmonary primary lymphoid lesion, consists of numerous reactive lymphoid follicles in a peribonchiolar distribution. Its precise cause is unknown, particularly in children, in which few cases have been reported. Treatment usually includes steroids and prognosis is generally good.