[A case of IgG4-positive multi-organ lymphoproliferative syndrome associated with Kimura disease].

A 46-year-old man, who had been treated for Kimura disease, was found to have abnormal findings on a chest radiograph. Chest CT showed a mass shadow in the right lower lobe. Histological findings of a transbronchial biopsy specimen showed inflammatory cells infiltrating the alveolar septum. Inflammatory cells consisted of plasma cells, lymphocytes and eosinophils. He had had sustained eosinophilia and elevation of IgE for 8 years, and his serum IgG and IgG4 (3480 mg/dl) levels were elevated. Contrast-enhanced computed tomography showed multiple low density areas in both kidneys. Since immunohistochemical staining of the lung specimens revealed infiltration of IgG4-positive plasma cells (IgG4-positive/IgG-positive plasma cells=35%), we diagnosed IgG4-positive multiorgan lymphoproliferative syndrome. The mass shadow had disappeared after treatment with celestamine (0.25 mg betamethasone and 2 mg dexchlorpheniramine) for Kimura disease, but another solid consolidation appeared in the contralateral lower lobe 5 months later. After the steroid dosage was increased, the consolidation improved. To the best of our knowledge, this case is the first report of IgG4-positive multi-organ lymphoproliferative syndrome associated with Kimura disease.