A case of B-cell lymphoma of Bronchus-Associated Lymphoid Tissue (BALTOMA) masquerading as an atypical interstitial pneumonia

We describe a 60-year-old patient with symptoms of chest pain, chronic non-productive cough, generalised malaise and weight loss for four years. Bilateral interstitial infiltrates were observed radiologically. Bronchoscopy with bronchoalveolar lavage (BAL) came back positive for Mycobacterium Xenopi. She was treated with rifampin, ethambutol and azithromycin for 6 months but no clinical improvement. She became progressively dyspneic and subsequently had a Video-assisted thorascopic surgery (VATS) and histological examination of lung biopsy revealed replacement of normal lung parenchyma with diffuse infiltration of monotonous cells with scanty cytoplasma and little nuclear irregularity. In immunohistochemical examination it was detected that the LCA and B cell markers of the cells were stained positive for CD20 and CD79; whereas epithelial markers were stained negative for cytokeratin and EMA, and T cell markers were stained negative for CD3. The molecular path revealed Ig heavy chain gene clonal rearrangement consistent with neoplastic proliferation of the B-cell lineage. These features were compatible with the diagnosis of primary pulmonary BALT (bronchus-associated lymphoid tissue) lymphoma or BALTOMA. We recommend that BALTOMA should be included in the differential diagnosis of patients with slow-progressing nonspecific pulmonary symptoms and radiographic interstitial infiltrates. Biopsy under CT guidance or VATS provides sufficient tissue in peripheral lung lesions for immunologic studies to assist in diagnosis.