Abstract
Follicular bronchiolitis (FB) is a rare bronchiolar disorder associated with hyperplasia of the bronchial-associated lymphoid tissue (BALT). It is characterized by the development of lymphoid follicles with germinal centers in the walls of small airways. It falls under the category of lymphoproliferative pulmonary diseases (LPDs) and commonly occurs in relation to connective tissue disease, immunodeficiency, infections, interstitial lung disease (ILD), and inflammatory airway diseases. Computerized tomography (CT) findings include centrilobular nodules with patchy ground glass infiltrate, tree-in-bud findings, and air trapping. It can very rarely present as diffuse cystic lung disease. We present two cases of FB. The first case is associated with Human Immunodeficiency Virus (HIV) infection and asthma with diffuse cystic changes on the CT. The second case is associated with reactive airway disease and gastroesophageal reflux disease (GERD) with the classic centrilobular nodules and ground glass opacities on the CT.
Highlights
One of the first reports of excessive lymphoid follicular formation in the diseased bronchioles was reported in 1952 by Whitewall when describing bronchiectasis [1]
Follicular bronchiolitis and its relation to bronchial-associated lymphoid tissue (BALT) was first described by Bienenstock et al in 1973. It is currently classified as a benign lymphoproliferative pulmonary disease (LPD) [2]. It is characterized by the development of lymphoid follicles with germinal centers in walls of the small airways
The patient’s evaluation for cystic lung disease included a negative folliculin gene test, ruling out Birt-Hogg-Dubé syndrome, and a normal serum vascular endothelial growth factor-D (VEGF-D) level arguing against lymphangioleiomyomatosis
Summary
One of the first reports of excessive lymphoid follicular formation in the diseased bronchioles was reported in 1952 by Whitewall when describing bronchiectasis [1]. Follicular bronchiolitis and its relation to bronchial-associated lymphoid tissue (BALT) was first described by Bienenstock et al in 1973. It is currently classified as a benign lymphoproliferative pulmonary disease (LPD) [2]. It is thought to be caused by antigenic stimulation and hyperplasia of BALT throughout the airway This may be the only characteristic finding, but in some cases, it can cause bronchiectasis and, rarely, present as a cystic lung disease. It can be primary/idiopathic or secondary and is associated with connective tissue disease, immunodeficiency states, and infections [3]
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