Androgen deprivation therapy caused a drastic proliferation of B-cell lymphoma with IgG4-related disease in patients with prostate cancer: a case report

Background We report a case of diffuse large B-cell lymphoma that progressed rapidly after androgen deprivation therapy for prostate cancer in a patient with a history of IgG4-related disease. Estrogen has been reported to be a possible cause of acute exacerbations of malignant lymphoma only in mouse models. Therefore, its clinical significance has not been clarified. Case presentation This case report describes a 75-year-old man with prostate cancer who had IgG4-related disease. Hormone therapy was initiated to treat prostate cancer, but he developed dyspnea and back pain. A diagnosis was made of diffuse large B-cell lymphoma. Immunohistochemistry was positive for estrogen receptor β, which led us to suspect rapid progression of diffuse large B-cell lymphoma due to estrogen suppression by gonadotropin-releasing hormone antagonists. Hormone therapy was discontinued, and the patient received R-CHOP therapy. Subsequently, the lymphoma masses shrunk, and the patient obtained remission. Conclusion This case is the first report of clinical significance regarding the crucial role of estrogen and estrogen receptor β in malignant lymphoma in a patient with IgG4-related disease. Our report aims to raise awareness of the need to carefully select treatment options for prostate cancer patients with IgG4-related disease or lymphoma.