Development of IgG4-related disease 10 years after chemotherapy for diffuse large B cell lymphoma and longstanding bronchial asthma.

Reported is a rare case IgG4-related disease that developed 10 years after combination chemotherapy for non-Hodgkin lymphoma. A 59-year-old Japanese man with longstanding bronchial asthma was referred to our hospital for bilateral hilar lymph node enlargement. The initial diagnosis was diffuse large B cell lymphoma (DLBCL) by supraclavicular lymph node biopsy. Serum IgG was high (4550 mg/dL) at diagnosis. The patient achieved complete response following six cycles of combination chemotherapy. Ten years later, bilateral submaxillary gland swelling was observed. Serum IgG and IgG4 were 2909 and 1470 mg/dL, respectively. The patient was diagnosed with IgG4-related disease by submandibular lymph node biopsy. Due to the difficulty in distinguishing IgG4-related disease from DLBCL through imaging findings alone, pathological confirmation of such lesions by biopsy is mandatory before proceeding to treatment.