Abstract
A 50-year-old male received medical treatment for chronic cough and lymphadenopathy. Because there was no improvement one month later, he was referred to our hospital. Elevation of the serum level of the soluble IL-2 receptor was noted, so a lymph node biopsy was performed. The pathological diagnosis was lymphadenitis, and malignant lymphoma was excluded from the differential diagnosis. An antibiotic was administered on an outpatient basis, but there was no improvement. Blood tests were done again, including additional parameters, and elevation of the serum level of IgG4 was found (1,100 mg/dℓ). A histological examination of the left submandibular gland and lymph nodes revealed infiltration by IgG4-positive plasma cells. Thus, the patient was diagnosed with IgG4-related disease. The size of the submandibular gland and lymph nodes decreased in response to treatment with prednisolone (PSL：30 mg/day). The patient's respiratory symptoms were also improved, and his serum IgG4 level was decreased. He is currently still receiving oral treatment with prednisolone (20 mg/day) and is in partial remission.
