Rituximab-induced hypersensitivity pneumonitis

Abstract

Rituximab is a chimeric anti-CD20 monoclonal antibody used to treat CD20+ non-Hodgkin's lymphoma. Although pulmonary adverse reactions such as cough, rhinitis, bronchospasm, dyspnea and sinusitis are relatively common, other respiratory conditions like cryptogenic organizing pneumonia, interstitial pneumonitis and diffuse alveolar hemorrhage have rarely been reported. Only 2 possible cases of rituximab-associated hypersensitivity pneumonitis have been described to date. We present a case of hypersensitivity pneumonitis with classic radiographic and histopathologic findings in a patient treated with rituximab who responded to prednisone.

Fig. 1.

Chest radiography shows bilateral infiltrates predominantly in the lower lobes.

Fig. 2.

Chest computed tomography shows ground-glass opacities, small centrilobular nodules (long arrow) and areas of decreased attenuation or mosaic pattern (short arrows). These findings are characteristics radiographic features of subacute hypersensitivity pneumonitis.

Fig. 3.

Transbronchial biopsy (HE, ×400) showing an increase in interstitial lymphocytes with a poorly formed granuloma (long arrow) and intraluminal fibrous plug (short arrows).