Primary Pulmonary Mucosa-associated Lymphoid Tissue Lymphoma with the High Expression of IgG4.

This is the first report describing primary pulmonary mucosa-associated lymphoid tissue (MALT) lymphoma with the high expression of IgG4. The histological findings were compatible with the diagnostic criteria for MALT lymphoma and IgG4-related respiratory disease (IgG4-RRD). An unfixed sample for Southern blotting was not obtained since computed tomography findings showed multiple lung cysts, which is rare in patients with MALT lymphoma.