AN UNUSUAL CASE OF PULMONARY CAVITARY LESIONS IN AN IMMUNOSUPPRESSED PATIENT

Abstract

SESSION TITLE: Medical Student/Resident Lung Pathology SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: October 18-21, 2020 INTRODUCTION: The differential diagnosis of pulmonary cavitary lesions is broad. They can be categorized in to infectious and non-infectious diseases, including neoplasms. Among malignancies, squamous cell carcinoma is a common cause of lung cavitation (1). Herein, we report a rare case of primary pulmonary diffuse large B-cell lymphoma (DLBCL) in a patient with rheumatoid arthritis that presented with multiple cavitary lesions and hypercalcemia. CASE PRESENTATION: 83-year-old male presented with hemoptysis, dyspnea, confusion, and constipation for several weeks. His past medical history was significant for tobacco abuse and interstitial lung disease from rheumatoid arthritis (RA) treated with methotrexate. CT chest showed bilateral cavitary lung lesions, left-pneumothorax and pneumomediastinum, needing chest-tube placement. Pulmonary function test showed a mild restrictive defect with a severe reduction in diffusion capacity. Labs showed hypercalcemia of 13.7 mg/dl, suppressed parathyroid hormone (PTH), elevated PTH-related peptide (PTHrp), and 1-25(OH) 2 Vitamin-D level. Quantiferon gold, sputum acid-fast bacilli and cultures were negative. Blood cultures (1/4 bottles) grew Actinomyces viscosus that was treated with 6-weeks of piperacillin-tazobactam. Bronchoscopy with lavage was unrevealing; however, due to a suspicion for malignancy with elevated PTHrp level, a CT-guided biopsy of left lower lobe lung mass was performed that confirmed a diagnosis of DLBCL, non-germinal center B-cell type. DISCUSSION: Pulmonary lymphoma is very rare and presents with nonspecific pulmonary symptoms (2). The pathogenesis of primary pulmonary DLBCL remains elusive. Patients with autoimmune disorders and recurrent bacterial infections are at a higher risk for developing DLBCL. Chest imaging may show nodular lesions, consolidation or interstitial /mixed alveolar infiltrates (2). DLBCL presenting with multiple cavitary lesions, is rarely reported. In our patient hypercalcemia was mediated by elevation of both PTHrp and 1-25(OH)2 Vitamin-D, which is unusual. Most primary pulmonary lymphomas (PPL) are low-grade mucosa-associated lymphoid tissue (MALT)-type, compared to more aggressive pulmonary diffuse large B-cell lymphoma (DLBCL), which is very uncommon (3). Most likely, our patient's autoimmune disorder (RA) and chronic methotrexate use contributed in the development of his DLBCL. CONCLUSIONS: We report a rare case of primary pulmonary DLBCL that manifested with multiple cavitary lesions and hypercalcemia. DLBCL must be considered in the differential diagnosis of cavitary lung lesions particularly in immunosuppressed patients. Reference #1: Chaudhuri MR. Primary pulmonary cavitating carcinomas. Thorax. 1973;28:354-366 Reference #2: Fujita N, Ando M, Goto A, Sakata M, Ogata M, Usagawa Y, et al. Diffuse large B-Cell lymphoma arising from the lesion of chronic lobar atelectasis. Tohoku J Exp Med. 2020;250(2):129–35. Reference #3: Brown S, Horton J, Rosario D, Dorsey DA, Hetz S, King CS. High-grade primary pulmonary B cell lymphoma presenting as a Necrotic mass. Respir Care. 2011 Jun 1;56(6):871–3. DISCLOSURES: No relevant relationships by Haytham Adada, source=Web Response no disclosure on file for Mahmoud Amarna; No relevant relationships by Pavan Annamaraju, source=Web Response No relevant relationships by Camelia Chirculescu, source=Web Response No relevant relationships by Nino Nemsadze, source=Web Response No relevant relationships by Sana Yakoob, source=Web Response