Medical Image of the Week: Pembrolizumab-induced Pneumonitis

Figure 1. Thoracic CT showing multifocal, bilateral extensive lung opacities consistent with consolidation with a striking peribronchovascular distribution. Note the opacities are primarily distributed along the airways. Peripheral lung opacity, both ground-glass opacity and consolidation, is also present.

Figure 2. Axial thoracic CT performed several months after Figure 1 following discontinuation of the pembrolizumab and initiation, and subsequent tapering, of corticosteroid therapy, shows significant regression in the previously noted extensive peribronchovascular consolidation. Residual areas of consolidation and ground-glass opacity associated with architectural distortion are consistent with scarring.

A 76-year-old man with metastatic melanoma, undergoing treatment with pembrolizumab, an antibody against programmed cell death 1 (PD-1), beginning 8 months ago developed low-grade fever, non-productive cough, and shortness of breath. A thoracic CT scan showed multifocal, bilateral extensive lung opacities (Figure 1). The patient underwent bronchoscopy with bronchoalveolar lavage which showed non-specific inflammatory changes associated with foci of organizing pneumonia. Microbiologic studies, including Coccioides antibody enzyme immunoassay and Aspergillus antigen, were negative.

The patient was begun on corticosteroid therapy for presumed medication-induced pulmonary injury, manifestation as an organizing pneumonia pattern, due to pembrolizumab. Over the ensuing months, his symptoms abated and his CT scan abnormalities regressed (Figure 2).

Organizing pneumonia may occur as an idiopathic, primary pulmonary process, often referred to as “cryptogenic organizing pneumonia,” or may occur in the context of a number of systemic conditions, a situation often referred to as secondary organizing pneumonia. Among the various etiologies of secondary organizing pneumonia, medication-induced pulmonary injury is fairly common and when imaging features of organizing pneumonia are seen, careful correlation regarding the possibility of a medication-induced etiology should be undertaken. Recently, three cases of pembrolizumab-induced pneumonitis were described, two being consistent with organizing pneumonia (1).

The thoracic CT findings of organizing pneumonia include peripheral and peribronchovascular consolidation and ground-glass opacity, areas of consolidation surrounding ground-glass opacity (often referred to as the “atoll” or reverse ground-glass halo” sign- see Medical Image of the Week: The Atoll Sign in Cryptogenic Organizing Pneumonia), single and multiple nodules, and perilobular consolidation. The case illustrates a dramatically peribronchovascular distribution of pulmonary consolidation as a manifestation of medication-induced organizing pneumonia.

Michael B. Gotway, MD

Department of Radiology

Mayo Clinic Arizona

Scottsdale, AZ USA

Reference

1. Leroy V, Templier C, Faivre JB, Scherpereel A, Fournier C, Mortier L, Wemeau-Stervinou L. Pembrolizumab-induced pneumonitis. ERJ Open Res. 2017 May 2;3(2). pii: 00081-2016. [CrossRef] [PubMed]

Cite as: Gotway MB. Medical image of the week: pembrolizumab-induced pneumonitis. Southwest J Pulm Crit Care. 2017;15(3):118-9. doi: https://doi.org/10.13175/swjpcc110-17 PDF 

Medical Image of the Week: Asbestos Related Pleural Disease

Figure 1. Chest radiograph demonstrates bilateral coarse calcification, most elongated and vertically oriented in nature (white arrows). Also note coarse calcification outlining the hemidiaphragms (dark arrows). Editor's note: the patient's only chest x-ray was two different AP views which are merged above.

Figure 2.  Holly leaf. Its shape is similar to the irregular thickened nodular edges of pleural plaques on chest radiograph, referred to as “the holly leaf sign”.

Figure 3. Thoracic CT shown in soft tissue (A: top) and lung (B: bottom) windows clearly localizes the calcifications to the parietal pleura.

Pleural plaques are strongly associated with inhalational exposure to asbestos (1). The lesions may take up to thirty years to develop. Plaques are typically bilateral, involve the parietal pleura, commonly along the sixth through ninth ribs and are usually absent at the lung apices and costophrenic sulci (Figures 1 and 3). On chest radiograph, the “holly leaf sign” refers to the shape of the calcifications with thickened rolled and nodular edges (Figure 2). The plaques per se are benign in nature. However, they can potentially impair lung function, resulting in restriction.  They are also markers of the individual’s greater risk of developing a lung cancer or mesothelioma.

Wesley Hunter MS IV¹, Veronica Arteaga MD², and Diana Palacio MD²

¹College of Medicine and ²Department of Medical Imaging

University of Arizona

Tucson, AZ USA

Reference

1. Norbet C, Joseph A, Rossi SS, Bhalla S, Gutierrez FR. Asbestos-related lung disease: a pictorial review. Curr Probl Diagn Radiol. 2015 Jul-Aug;44(4):371-82. [CrossRef] [PubMed] 

Cite as: Hunter W, Arteaga V, Palacio D. Medical image of the week: asbestos related pleural disease. Southwest J Pulm Crit Care. 2017;15(3):116-7. doi: https://doi.org/10.13175/swjpcc104-17 PDF