Cavitary pulmonary involvement of diffuse large B-cell lymphoma transformed from extra nodal marginal zone B-cell lymphoma MALT type.

We describe a case of pulmonary diffuse large B-cell lymphoma (DLBCL), which was thought to arise from extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma). A 68-year-old woman presented with a 2-month history of cough and bloody sputum. The chest X-ray and computed tomography revealed a mass with cavitation in the right lower lobe. Transbronchial biopsy specimens revealed a granulomatous infiltration without malignant cells. However, diagnosis of MALT lymphoma was established from gastric biopsy specimen. Subsequently, a right lower lobectomy was performed because of hemoptysis. Examination of the resected specimen revealed a diffuse large B-cell lymphoma, which was considered to have transformed from MALT lymphoma, because both lung and stomach lesions had the chromosomal translocation t(11;18)(q21;q21) in common. In addition, there were no nodules, masses, alveolar or interstitial infiltrates in the lung fields, which are usually observed in the case of marginal zone B-cell lymphoma of bronchial mucosa-associated lymphoid tissue. These findings indicate that involvement of DLBCL have to be considered in patients with MALT lymphoma and cavitary lesion of the lung.