Follicular bronchiolitis (pathology proven) in a patient with common variable immunodeficiency (CVID)

DISCUSSION

Follicular bronchiolitis is defined as polyclonal peribronchilar lymphoid hyperplasia. Many cases of follicular bronchiolitis are associated with various systemic illnesses including connective tissue diseases ( Sjogren syndrome, rheumatoid arthritis ), immunodeficiency states   (CVID, AIDS ), hypersensitivity disorders associated with peripheral eosinophilia. It can be also familiar or idiopathic. As opposite to lymphoid interstitial pneumonia, follicular bronchiolitis is limited to the airways without diffuse interstitial involvement.

The differential diagnosis for CT findings includes:   infection, hypersensitivity pneumonitis, and respiratory bronchiolitis. Surgical lung biopsy is usually necessary to establish the diagnosis. The prognosis is generally good, however younger patient may develop progressive disease.

CT findings of follicular bronchiolitis include small centrilobular nodules 1 to 12 mm in size, usually less than 3 mm, occasionally with a tree-in-bud configuration. In addition, peribronchial nodules, nodules along the septa and pleura, ground glass opacities, and cysts may be seen. Infrequent findings include bronchiectasis, bronchial wall thickening, and peribronchovascular consolidation.

CVID is the most common symptomatic primary immunodeficiency characterized by hypogammaglobulinemia (usually also decrease of IgA and/or IgM antibodies) and recurrent infections (most frequent with H. influenzae, S. pneumoniae and S. aureus). CT chest findings include bronchiectasis possibly with interstitial lung disease, pulmonary nodules, ground glass opacities, as well as intrathoracic or intra-abdominal lymphadenopathy and/ or hepatosplenomegaly.

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