Abstract
Case 1: A 68-year-old man had a 10-year history of repeated episodes of exudative erythema with pruritus on his upper and lower extremities. Cervical and axillary lymphadenopathy, parotid and submandibular sialoadenitis, and renal dysfunction with proteinuria also developed during this time. Histopathologically, renal biopsy specimens showed an IgG4-positive plasmacyte infiltration, and skin biopsy specimens showed an infiltration of IgG4-positive plasmacytes and eosinophils into the dermis based on these histopathological findings and the increased serum IgG4, he was diagnosed with IgG4-related disease. His clinical findings disappeared after administration of oral steroids, but relapsed after discontinuation of the drug. Case 2: A 74-year-old man visited our department for evaluation of red papules with strong pruritus on his lower extremities and CT findings of sclerosing cholangitis, pulmonary fibrosis, and retroperitoneal fibrosis. Histopathologically, duodenal diverticulum biopsy specimens showed IgG4-negative plasmacyte and eosinophil stromal infiltration, which was compatible with asymptomatic cholangitis. Skin biopsy specimens showed IgG4-negative plasmacyte and eosinophil upper dermal infiltration. IgG4-related disease was diagnosed based on these histopathological findings, CT findings of mass lesions with fibrosis, and increased serum IgG4. The skin eruptions in both of our cases were considered to be symptoms of IgG4-related disease. The combination of the dermal eosinophil infiltration, serum eosinophilia, and increased TARC level suggests that Th2 cells might be involved in the pathogenesis of these lesions.
