TOPIC: Diffuse Lung Disease TYPE: Medical Student/Resident Case Reports INTRODUCTION: Chronic cavitary pulmonary aspergillosis (CCPA) is a rare form of aspergillosis involving patients with structural lung diseases. Here we will describe a case of CCPA in a patient with idiopathic pulmonary fibrosis (IPF), which is rarely reported. CASE PRESENTATION: The patient was a 78-year-old male with a medical history significant for IPF diagnosed 13 years prior, on oral pirfenidone and long-term oxygen therapy, who presented to the hospital for worsening shortness of breath, productive cough, and fatigue of two months duration. The patient was initially hospitalized in another facility for the above symptoms where he received two courses of antibiotics without significant improvement. Chest examination showed bilateral fine inspiratory crackles, worse on the right side. The results of routine blood tests were normal. The nasal swab for the respiratory viral panel was negative. Chest X-ray showed fibrotic lung disease with a superimposed alveolar and interstitial process involving the lung bases and right upper lobe. Computed Tomography (CT) scan of the chest was suggestive of a thick-walled cavitary lesion in the right apex measuring 4.8 x 3.3 cm, enlarged mediastinal and right hilar lymph nodes along with other chronic changes. Three sets of sputum acid-fast bacilli (AFB) smears along with serum Quantiferon TB gold plus test were negative. The patient was empirically started on intravenous (IV) ceftriaxone and azithromycin. Later, blood and sputum cultures were reported negative for bacteriological growth. Interestingly, the sputum cultures were positive for Aspergillus species along with positive serum Aspergillus immunoglobulin (Ig)G level. The patient was diagnosed with CCPA based on the serology, culture results, and radiological findings. IV antibiotics were discontinued and the patient was started on oral posaconazole 300 mg daily resulting in clinical improvement. Currently, the patient is on a 6-month posaconazole regimen. DISCUSSION: Pulmonary aspergillosis is a common opportunistic infection that can present as aspergilloma, allergic bronchopulmonary aspergillosis, CCPA, and invasive pulmonary aspergillosis based on lung changes. Mycobacterium infection and obstructive lung diseases are the most frequent underlying pulmonary diseases that are associated with CCPA. However, IPF with CCPA is rare, and its clinical features and radiological findings lack specificity leading to delays in diagnosis and treatment. Once confirmed, the treatment is straightforward with long-term triazole antifungals. CONCLUSIONS: In a patient with IPF, presenting with rapidly progressing radiologic findings suggestive of pulmonary cavitation, CCPA should be considered in the differential diagnosis. REFERENCE #1: Liu C, Yang J, Lu Z. Idiopathic pulmonary fibrosis with chronic necrotizing pulmonary aspergillosis: a case report. Int J Clin Exp Pathol. 2019 Jul 1;12(7):2653-2656. PMID: 31934094; PMCID:PMC6949565 REFERENCE #2: Graham KG, Nasir A. Chronic Cavitary Pulmonary Aspergillosis: A Case Report and Review of the Literature. Am J Case Rep. 2019 Aug 18;20:1220-1224 doi: 10.12659/AJCR.915893. PMID: 31422416; PMCID: PMC6711266. REFERENCE #3: Sehgal IS, Dhooria S, Muthu V, Prasad KT, Agarwal R. An overview of the available treatments for chronic cavitary pulmonary aspergillosis. Expert Rev Respir Med. 2020 Jul;14(7):715-727. doi: 10.1080/17476348.2020.1750956. Epub 2020 Apr 20. PMID: 32249630. DISCLOSURES: No relevant relationships by Rabab Elmezayen, source=Web Response No relevant relationships by Syed yousaf Shah, source=Web Response