GRANULOMATOUS LUNG DISEASE: A DIAGNOSTIC DILEMMA

Abstract

SESSION TITLE: Fellows Diffuse Lung Disease Posters SESSION TYPE: Fellow Case Report Posters PRESENTED ON: October 18-21, 2020 INTRODUCTION: Granulomatous lung disease (GLD) refers to a large group of infectious and noninfectious diseases. Granulomas are collections of macrophages with giant cells. GLD are diagnostically challenging and require thorough investigation from clinical context and family history to radiographs and biopsy. Often, a diagnosis may still elude the investigator. CASE PRESENTATION: A 53-year-old Italian female presented with intermittent low-grade fevers, nonproductive cough and pleuritic chest pain for several months and was found to be hypoxemic with exertion. She was a non-smoker and a runner who travelled internationally for work conferences and owned cats. Initial evaluation revealed hypoxemia with exertion, peripheral eosinophilia and an elevated C-reactive protein (CRP). Chest x-ray (CXR) was unremarkable but computed tomography (CT) showed bibasilar, centrilobular tree-in-bud nodularity without lymphadenopathy [Figure 1-2]. Bronchoscopy revealed a sterile lymphocytosis. A video-assisted thoracoscopic surgery (VATS) biopsy was done which showed peribronchovascular and subpleural non-caseating granulomas with giant cells and plugs of organizing pneumonia. These findings were suggestive of sarcoidosis with atypical radiologic features; however, external review by a separate pathologist suggested hot tub lung syndrome as a possibility. DISCUSSION: This case posed several radiologic and pathologic challenges. Centrilobular nodules are seen in hypersensitivity pneumonitis (HP), asbestosis, Langerhans cell histiocytosis (LCH) and bronchiolitis, the latter of which can be seen as tree-in-bud along with aspiration. The differential for GLD is broad and includes infection (tuberculosis, non-tuberculous mycobacterium (NTM), endemic fungi) and noninfectious etiologies (lymphoma, ANCA-associated vasculitides, LCH, inflammatory bowel disease, drug-induced, sarcoidosis and exposure related diseases such as HP, hot tub lung syndrome and pneumoconiosis). Peribronchovascular granulomas suggested sarcoidosis, but other classic radiologic features of sarcoidosis were absent. ACE and calcium levels were normal and there was no other obvious organ involvement. The imaging did fit with hot tub lung syndrome and she had granulomas in the airways as well as hot tub exposure but cultures were negative for NTM. After extensive infectious and rheumatologic workup was negative, she was trialed on empiric steroids and had symptomatic resolution. CONCLUSIONS: It is important to understand the etiology of infectious and noninfectious GLDs as treatments vary depending on the cause. In our case, we were unable to identify the single, unifying diagnosis despite thorough investigation. A noninfectious etiology was presumed and steroids ultimately proved to be successful. Reference #1: Cheung OY, et al. Surgical Pathology of Granulomatous Interstitial Pneumonia. Ann Diagn Pathol. 2003; 7(2):127-38. doi: 10.1053/adpa.2003.50018. Reference #2: Crouser ED, Maier LA, Wilson KC, et al. Diagnosis and Detection of Sarcoidosis. Am J Respir Crit Care Med. 2020; 201(8):e26-e51. doi: 10.1164/rccm.202002-0251ST. Reference #3: Swensen SJ, et al. Lung Nodule Enhancement at CT: A Multicenter Study. Radiology. 2000; 214(1):73-80. doi: 10.1148/radiology.214.1.r00ja1473. DISCLOSURES: No relevant relationships by Cristina Reichner, source=Web Response No relevant relationships by Jigna Solanki, source=Web Response