Pulmonary Nodular Lymphoid Hyperplasia Evaluated with Bronchoalveolar Lavage Fluid Findings: A Case Report and Review of the Literature on Japanese Patients

Pulmonary nodular lymphoid hyperplasia (PNLH) is a very rare disease, and it is difficult to diagnose PNLH and distinguish it from mucosa-associated lymphoid tissue (MALT) lymphoma. In addition, information on bronchoalveolar lavage fluid (BALF) analyses is lacking. We herein report a 36-year-old Japanese woman diagnosed with PLNH by a surgical biopsy and analysis of BALF. The BALF showed an increase in B-cell marker-positive lymphocytes, normal patterns of B-cell clonality, mucosa-associated lymphoid tissue 1 gene, and immunoglobulin heavy chain at 14q32 translocations. We also reviewed Japanese cases of PNLH described in Japanese or English to explore the characteristics of such cases.