Mucosa-Associated Lymphoid Tissue Lymphoma of the Lung

Mucosa-associated lymphoid tissue lymphoma (MALToma) of the lung is a rare, low-grade B-cell lymphoma arising from bronchus-associated lymphoid tissue. A case of primary pulmonary MALToma in an elderly patient who presented with a solitary infiltrate on chest radiographic image, which was confirmed by the detection of rearranged immunoglobulin heavy chain genes using polymerase chain reaction (PCR) is described. Transbronchial lung biopsy (TBLB) specimens showed angulated lymphoid cells with lymphoepithelial lesions. Immunohistochemistry revealed that the lymphoid cells were positive for CD20 and Λ light chain. Furthermore, the PCR approach using formalin-fixed, paraffin-embedded sections of TBLB specimens demonstrated the rearrangement of the immunoglobulin heavy chain. TBLB combined with PCR screening is a valuable and relatively noninvasive method for diagnosing primary pulmonary MALToma.