SESSION TITLE: Interstitial Lung Disease Case Report Posters II
SESSION TYPE: Affiliate Case Report Poster
PRESENTED ON: Tuesday, October 29, 2013 at 01:30 PM - 02:30 PM
INTRODUCTION: Rituximab, in several case reports, has been shown to cause various pulmonary toxicities including organizing pneumonia. To our knowledge, this is the first case of biopsy-proven concomitant constrictive bronchiolitis and organizing pneumonia associated with rituximab.
CASE PRESENTATION: A 58 year-old man with follicular lymphoma status post 6 cycles of rituximab, cyclophosphamide, vincristine and prednisone presented with gradual, progressive dyspnea on exertion beginning eight weeks after his last chemotherapy. His exercise tolerance was limited to climbing 1/2 a flight of stairs and he had audible wheezing with exertion. He was a lifelong nonsmoker and denied any inhalational exposures. On exam, his oxygen saturation was 94%. He had diminished breath sounds throughout his lung fields with expiratory wheezing at the bases. An arterial blood gas was significant for a PaO2 of 66. Chest x-ray was normal. Pulmonary function tests showed a very severe obstructive ventilator defect with air trapping, hyperinflation, and diffusion impairment. Serial CT thorax scans over the next few months were significant for fleeting airspace opacities and pulmonary nodules. A bronchoscopy with transbronchial biopsies ruled out infection but was nondiagnostic. Surgical wedge biopsy of the lung was done with pathology showing constrictive bronchiolitis with fibrosis, chronic inflammation and narrowing of airways; deeper sections showed a very focal organizing pneumonia pattern adjacent to the obstructed airways. The patient was treated with corticosteroids for the organizing pneumonia and his CT thorax normalized. However, the patient remains symptomatic from constrictive bronchiolitis and his pulmonary function tests continue to decline.
DISCUSSION: Rituximab is an anti-CD20 monoclonal antibody used in the treatment of non-Hodgkin lymphomas and has been previously shown to induce organizing pneumonia. Constrictive bronchiolitis, distinct from organizing pneumonia, is a rare fibrotic disorder that leads to progressive airflow obstruction and obliteration of terminal and respiratory bronchioles. Prior to our patient, constrictive bronchiolitis had been postulated to be a pulmonary toxicity of rituximab in one case report in the literature. Due to the timing of onset of our patient’s symptoms, the constrictive bronchiolitis and organizing pneumonia were consistent with pulmonary toxicities from rituximab.
CONCLUSIONS: Constrictive bronchiolitis is a pulmonary toxicity associated with rituximab that carries a high mortality. Organizing pneumonia caused by rituximab is responsive to steroids and can be seen concomitantly with constrictive bronchiolitis.
Reference #1: Lynch JP, Weight SS, DerHovanessian A, et al. Obliterative (Constrictive) Bronchiolitis. Semin Respir Crit Care Med 2012; 33(05): 509-532.
Reference #2: Shen T, Braude S. Obliterative Bronchiolitis After Rituximab Administration: A New Manifestation of Rituximab Associated Pulmonary Toxicity. Intern Med Journ 2012; 42 (5): 597-599.
DISCLOSURE: The following authors have nothing to disclose: Joanne Martires, Nikhil Barot, Nader Kamangar
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