A80-3-20 Chronic Cough Secondary to Endobronchial Mucosal-Associated Lymphoid Tissue (MALT) Lymphoma

Abstract Introduction Primary pulmonary lymphoma, defined as lymphoid proliferation originating from the lungs, is a rare disease that represents just 0.5-1.0% of primary pulmonary neoplasms, with MALT Lymphoma representing more than 80% of these cases (1). Pulmonary MALT lymphoma typically presents as multinodular and bilateral disease with no specific distribution (2). However, endobronchial presentations of pulmonary MALT lymphoma are exceedingly rare and may mimic more common airway pathologies such as asthma or benign strictures, leading to potential misdiagnosis and treatment delay. We present a case of primary endobronchial MALT lymphoma confined to the bronchus intermedius with an initial presentation of chronic cough. Case Presentation A 56-year-old female with a past history of asthma, previous 34-pack-year smoking history, and gastroesophageal reflux disease (GERD) presented to the Lehigh Valley Physicians Group Pulmonary and Critical Care Medicine office with 6 months of chronic cough refractory to standard treatments. Initial spirometry revealed a mild to moderate obstructive pattern without significant bronchodilator response with suspicion for cough variant asthma with plan to manage with as needed albuterol nebulizer, daily fluticasone/umeclidinium/vilanterol, and a non-contrast CT Chest to evaluate airway and parenchyma. Follow up at one month showed a similar pattern of spirometry despite medication adherence, and CT chest revealed a lesion compressing the bronchus intermedius. Subsequent PET-CT scan was significant for right middle lobe atelectasis with narrowing of bronchus intermedius, but no metabolically suspicious findings. Bronchoscopy with biopsy was then performed to evaluate the lesion, with pathology significant for a markedly expanded CD5 and CD10 negative B-cell population with no MYD88 mutation and normal fluorescence in situ hybridization (FISH), consistent with marginal zone lymphoma. The patient was referred to hematology-oncology for treatment with weekly rituximab for four weeks and a follow up CT Chest in eight weeks. Post-treatment CT revealed no evidence of overt measurable tumor in the chest. Conclusion This case highlights that pulmonary MALT lymphoma may present solely as an endobronchial lesion, concealed by non-specific symptoms and absent metabolic activity on PET-CT. Early bronchoscopy is critical for diagnosis in patients with central airway obstruction and refractory cough. Increased awareness of this presentation may facilitate earlier detection and targeted therapy, improving outcomes. References: 1) Cadranel J, Wislez M, Antoine M. Primary pulmonary lymphoma. Eur Respir J. 2002 Sep;20(3):750-62. doi: 10.1183/09031936.02.00404102. 2) Borie R, Wislez M, Antoine M, Copie-Bergman C, Thieblemont C, Cadranel J. Pulmonary mucosa-associated lymphoid tissue lymphoma revisited. Eur Respir J. 2016 Apr;47(4):1244-60. doi: 10.1183/13993003.01701-2015. This abstract is funded by: None