BRONCHIAL-ASSOCIATED LYMPHOID TISSUE LYMPHOMA (BALTOMA) PRESENTING AS A NONRESOLVING PNEUMONIA

Abstract

SESSION TITLE: Lung Pathology 2 SESSION TYPE: Fellow Case Report Posters PRESENTED ON: 10/09/2018 01:15 PM - 02:15 PM INTRODUCTION: Pulmonary mucosa-associated lymphoid tissue lymphoma (also known as bronchial associated lymphoid tissue lymphoma or BALToma) is a rare type of extranodal marginal zone B-cell lymphoma. Marginal zone lymphomas in other parts of the body have been associated with chronic antigen stimulation, such as in autoimmune disease. Pathogenesis from chronic infection has been hypothesized but a causative organism or antigen has not been identified for the lungs. We present a soldier with initial infectious symptoms who had persistent dense pulmonary consolidation that was found to be a BALToma. CASE PRESENTATION: 48 year old male underwent chest x-ray for cough and dyspnea on exertion that developed shortly after returning from deployment to Afghanistan. He was found to have a right middle lobe consolidation on chest radiograph that was redemonstrated along with multiple bilateral ground glass opacities on confirmatory chest CT. His symptoms resolved after treatment with oral azithromycin and follow-up chest radiograph 3 weeks later showed improvement in the right middle lobe consolidation. Chest imaging two years later while asymptomatic revealed persistent, slightly enlarged right middle lobe consolidation and persistent bilateral ground glass lesions. PET-CT of the chest, abdomen, and pelvis showed hypermetabolism (SUV-m of 3.7) limited to the pulmonary mass without any other hypermetabolic foci. There was a single pathologic-sized right paratracheal lymph node measuring up to 1.5 cm that showed normal FGD activity. Bronchoscopy with bronchial brushing, fine needle aspiration, and transbronchial forceps biopsy of the mass revealed a dense infiltrate composed of small B-cells that tested positive for the MALT1 translocation (t(11;18)), consistent with a BALToma. No infectious organism was isolated. DISCUSSION: Bronchial associated lymphoid tissue lymphoma is a slow growing malignant pulmonary tumor. Clinical manifestations are usually nonspecific and the majority of patients are asymptomatic at diagnosis. Biopsy sample of a BALToma are characterized by presence of a nodular lymphoid infiltrate expanding the marginal zone of reactive lymphoid follicles with tumor cells infiltrating the bronchiolar or the alveolar epithelium. The diagnosis is confirmed via immunohistochemical analysis that excludes lung localization of other lymphomas such as mantle cell and follicular lymphoma. PCR or FISH probes for the MALT1 gene can be supportive. Diagnosis may be missed due to the radiographic similarity to community acquired pneumonia, but appropriate diagnosis is important since this process typically responds well to therapy. CONCLUSIONS: BALToma should be considered in the differential of asymptomatic patients with imagining suggest of persistent nonresolving pneumonia. Reference #1: Borie R, Wislez M, Antoine M, et al. Pulmonary mucosa-associated lymphoid tissue lymphoma revisited. Eur Respir J. 2016 Apr;47(4):1244-60 DISCLOSURES: No relevant relationships by Benjamin Rosen, source=Web Response No relevant relationships by Krystle Salazar, source=Web Response No relevant relationships by John Sherner, source=Web Response