The Story Of A Lung Mass: It'S Not Always A Cancer

SESSION TITLE: Fellows Chest Infections Posters SESSION TYPE: Fellow Case Report Posters PRESENTED ON: October 18-21, 2020 INTRODUCTION: Nocardiosis is an uncommon gram-positive bacterial infection caused by aerobic Actinomycetes. It presents as a localized or systemic suppurative disease. Pulmonary nocardiosis isn't an uncommon disease, seen usually in immunocompromised patients. However, 35 % of cases have been reported in an immunocompetent host. We present a case of pulmonary nocardiosis presenting as a lung mass. CASE PRESENTATION: A 52-year-old male, nonsmoker, with a history of focal segmental glomerulosclerosis on immunosuppression with steroids and cyclosporine, congestive heart failure, atrial fibrillation and chronic kidney disease presented to the hospital with shortness of breath, blood-tinged sputum, and bilateral lower extremity edema. His vital signs were unremarkable and physical examination was notable for mild wheezing bilaterally. Lab workup revealed leukocytosis and transaminitis. Blood cultures showed no growth, sputum cultures were negative. Chest x-ray showed left upper lobe pulmonary opacity, which subsequently evolved into a cavitary lesion. A Chest CT revealed 4.6 cm left upper lobe mass with ground-glass and surrounding hemorrhage concerning for tumor versus fungal infection. Patient proceeded with a CT-guided biopsy of the lung which showed lung parenchyma with organizing fibrinous changes suggestive of acute inflammation. Gram stain demonstrated, Gram-positive branching filamentous bacteria, consistent with Nocardia species. Cultures grew Nocardia cyriacigeorgica. MRI brain revealed two small lesions, suspicious for systemic nocardiosis. The patient was treated with ceftriaxone and Bactrim for 6 weeks and 12 months respectively with clinical improvement. DISCUSSION: Pulmonary nocardiosis can present as acute, subacute or chronic disease. It can belocalized or can manifest as systemic suppurative disease. It typically presents as an opportunistic infection, however 1/3 of the infected patients are immunocompetent. The lungs are the primary site of nocardial infection in more than two-thirds of cases. Radiographic findings of lung involvement are variable and include single or multiple nodules, lung masses, reticulonodular infiltrates, interstitial infiltrates, lobar consolidation, subpleural plaques, and pleural effusions. CNS disease accounts for approximately 20 percent of Nocardia cases. In the proper clinical setting, a presumptive diagnosis of nocardiosis can be made if partially acid-fast filamentous branching rods are visualized in clinical specimens. CONCLUSIONS: Pulmonary nocardiosis is a rare diagnosis. It can occur in immunocompromised and immunocompetent patient without any underlying chronic lung disease. It can present as a lung mass or cavitary lesion. Systemic nocardiosis should be a differential in mind for immunocompromised patients presenting with cavitating pulmonary mass. Reference #1: Shariff M, Gunasekaran J. Pulmonary Nocardiosis: Review of cases and an update. Can Respir J. 2016;2016:7494202 Reference #2: Sato H, Okada F, Mori T, et al. High-resolution Computed Tomography findings in patients with Pulmonary Nocardiosis. Acad Radiol. 2016;23(3):290-296. DISCLOSURES: No relevant relationships by Saman Ahmed, source=Web Response No relevant relationships by Sofiya Rehman, source=Web Response