[Pulmonary hyalinizing granuloma with massive infiltration of lymphocytes]

A 39-year-old man was admitted to our hospital for examination of multiple nodules and infiltrates on a chest radiograph. His chest HRCT revealed multiple nodules with or without thick- or thin-walled cavities. Specimens obtained by video-assisted thoracoscopic biopsy showed bundles of hyalinized collagen fibers, some of which contained accumulated plasma cells in the center. The nodules were surrounded by massive lymphoid cells which formed germinal centers. These findings are compatible with pulmonary hyalinizing granuloma. The lymphoid cells looked uniform in some areas and had infiltrated along the bronchioles and small vessels and into the intralobular septa in a manner resembling pulmonary lymphoma or pseudolymphoma. The findings suggested that pulmonary hyalinizing granuloma may overlap pulmonary lymphoma. The disease has shown no progression for four years although no treatment has been given.