Lymphoid interstitial pneumonia as a pulmonary lesion of idiopathic plasmacytic lymphadenopathy with hyperimmunoglobulinemia.

A case of idiopathic plasmacytic lymphadenopathy with hyperimmunoglobulinemia is reported. A 71-year-old man was admitted to the hospital because of the abnormal shadow on chest roentgenogram. Chest X-ray taken on admission showed remarkable diffuse infiltration and pleural thickening. Laboratory examinations revealed an elevated total protein level of 10.1 g/dl, and a gammaglobulin level of 7.0 g/dl including 6,790 mg/dl IgG. Mediastinal lymphadenopathy was observed on a chest CT. The patient underwent open lung biopsy. Heavy infiltration of lymphocytes and plasma cells were seen in the moderately fibrotic pulmonary interstitium. LIP was diagnosed. Lymph node biopsy was also performed. Follicular hyperplasia with prominent germinal centers and plasma cell proliferation in the interfollicular area were seen. Treatment with prednisolone resulted in an improvement in the chest X-ray findings, as well as a diminished polyclonal hypergammaglobulin level.