High-resolution computed tomography and histopathological findings in hypersensitivity pneumonitis: a pictorial essay

Abstract

Hypersensitivity pneumonitis is a diffuse interstitial and granulomatous lung disease caused by the inhalation of any one of a number of antigens. The objective of this study was to illustrate the spectrum of abnormalities in high-resolution computed tomography and histopathological findings related to hypersensitivity pneumonitis. We retrospectively evaluated patients who had been diagnosed with hypersensitivity pneumonitis (on the basis of clinical-radiological or clinical-radiological-pathological correlations) and had undergone lung biopsy. Hypersensitivity pneumonitis is clinically divided into acute, subacute, and chronic forms; high-resolution computed tomography findings correlate with the time of exposure; and the two occasionally overlap. In the subacute form, centrilobular micronodules, ground-glass opacities, and air trapping are characteristic high-resolution computed tomography findings, whereas histopathology shows lymphocytic inflammatory infiltrates, bronchiolitis, variable degrees of organizing pneumonia, and giant cells. In the chronic form, high-resolution computed tomography shows traction bronchiectasis, honeycombing, and lung fibrosis, the last also being seen in the biopsy sample. A definitive diagnosis of hypersensitivity pneumonitis can be made only through a multidisciplinary approach, by correlating clinical findings, exposure history, high-resolution computed tomography findings, and lung biopsy findings.

Idiopathic interstitial pneumonias: review of the latest American Thoracic Society/European Respiratory Society classification

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Diagnostic Approach to Hypersensitivity Pneumonitis: A Report of Two Cases

“…The basic management strategy in HP is to identify antigen exposure and fully avoid the problematic antigen (recommended). Corticosteroids are given in situations when there is no remission with antigen avoidance [ 6 ]. Some patients previously diagnosed with certain types of fibrotic interstitial lung diseases (f-ILDs), including fibrotic HP (f-HP), are susceptible to developing a progressive fibrosing phenotype (PF-ILD), despite initial state-of-the-art management.…”

Is It Idiopathic Pulmonary Fibrosis or Not?

“…Third, CHP frequently demonstrates air trapping on expiratory CT images. 41 Air trapping is infrequently associated with a UIP pattern and when present a diagnosis of rheumatoid arthritis should be considered.…”