[A case of plasma cell granuloma with good response to steroid therapy].

A 46-year-old man was admitted with complaints of fever, cough and anterior chest pain. Chest X-ray examination disclosed an infiltrative shadow in the right upper lung field and chest CT scan strongly suggested invasion of mediastinum and anterior chest wall. Therefore, steroid therapy was selected because biopsy specimen showed proliferation of fibroblasts and mononuclear cells mainly containing plasma cells with no evidence of malignancy. After steroid therapy, chest X-ray examination showed that the infiltrative shadow was greatly reduced. However, since infiltrative shadow was increased again at 3 years after the initiation of steroid therapy, right upper lobectomy was performed. Histopathological analysis of resected tumor demonstrated proliferation of mature plasma cells and fibroblasts in conjunction with minor infiltration of neutrophils and lymphocytes. At 18 months after operation, new shadows appeared in right S8 and S10 which were shown to have almost the same histological findings as the resected tumor. Steroid therapy was restarted, and then the size of shadows decreased. It is conceivable that steroid therapy is an effective therapy for pulmonary plasma cell granuloma, especially multifocal and relapsing cases.