INCIDENTAL FINDING OF PULMONARY MUCOSA-ASSOCIATED LYMPHOID TISSUE LYMPHOMA

Abstract

TOPIC: Lung Cancer TYPE: Medical Student/Resident Case Reports INTRODUCTION: Primary pulmonary lymphomas (PPLs) comprise 1% of lung neoplasias, with pulmonary mucosa associated lymphoid tissue (MALT) lymphoma making up approximately 80% of these lesions. Pulmonary MALT lymphoma is a rare extranodal marginal zone B-cell lymphoma that is typically indolent in nature. Clinical manifestations of pulmonary MALT include fever, malaise, cough, dyspnea, and chest pain, although 30% of patients can be asymptomatic. We present a case of an incidental discovery and diagnosis of pulmonary MALT lymphoma. CASE PRESENTATION: 72-year-old male lifelong non-smoker with medical history of hypertension presented to pulmonology clinic due to incidental central left lower and perihilar ground glass density seen on CT performed for coronary calcium scoring. He denied symptoms, and his physical examination and laboratory values were normal. Follow-up CT chest with contrast showed a persistent 3.5 cm ground-glass lesion in the superior segment of the left lower lobe. Navigational bronchoscopy with biopsy and bronchoalveolar lavage was performed. The pathology revealed bronchial mucosa with a dense atypical lymphoid infiltrate and predominance of CD20 positive and CD5 negative B lymphocytes. These findings were consistent with a lymphoproliferative disorder of MALT lymphoma. FDG PET-CT demonstrated moderate uptake in the left lower lobe nodule with no other significant uptake elsewhere in the body. The patient was evaluated by medical oncology and is undergoing active surveillance with repeat CT anticipated in 3 months. DISCUSSION: Onset of PPL occurs around 50-60 years of age and the rate of smoking in these patients is not higher than that of the general population. Pulmonary MALT lymphoma is associated with chronic antigen stimulation, but unlike other MALT lymphomas, they have not yet been associated with chronic infection. They are often associated with cytogenetic abnormalities, 42% of cases having the translocation t(11;18)(q21;q21). Diagnosis is made by tissue biopsy, usually bronchoscopic versus CT guided. Pathology and immunohistochemistry are significant for lymphoid infiltrates expanding lymphoid follicle marginal zones with CD20 positive and CD5 negative cells. Treatment options include chemotherapy, radiation therapy, immunotherapy, surgical management, or an expectant approach in cases of limited disease. Overall five-year survival for patients is greater than 80%. CONCLUSIONS: The pathogenesis of pulmonary MALT lymphoma is not well understood. Due to its rare occurrence, there are limited studies of treatment of these lymphomas and therefore no true consensus regarding best treatment strategies. With slow growth rates, a watch and wait plan may be a suitable approach to isolated pulmonary lesions and has not been shown to negatively affect overall survival. However, a better understanding of the pathophysiology and optimal treatment of these lymphomas requires further studies. REFERENCE #1: Sanguedolce F, et al. Primary pulmonary B-cell lymphoma: A review and update. Cancers. 2021; 13(3): 415. REFERENCE #2: Borie R. Pulmonary mucosa-associated lymphoid tissue lymphoma revisited. Eur Respir J. 2016;47(4):1244-60 REFERENCE #3: Yan W. Watch-and-wait or immediate immunotherapy/immunochemotherapy in patients with phase IE primary pulmonary MALT lymphoma? A multicenter retrospective study. Annals of Hematology. 2021; 100(3): 709-714. DISCLOSURES: No relevant relationships by Nicole Bernskoetter, source=Web Response Speaker/Speaker's Bureau relationship with Astra Zeneca, GSK Please note: $1001 - $5000 by Daniel Gerardi, source=Web Response, value=Honoraria No relevant relationships by Simrina Sabharwal, source=Web Response