IgG4-Related Prostatitis Impairs Objective Urinary Function as with Benign Prostate Hyperplasia: A Case Report Successfully Treated with Transurethral Resection.

1 Case We report a case of IgG4-related prostatitis successfully treated with transurethral resection of the prostate (TUR-P). A 47-year-old man with a history of autoimmune pancreatitis and sclerosing cholangitis presented with lower urinary tract symptoms. Because ultrasonography revealed a mildly enlarged prostate and uroflowmetry showed a severely diminished flow curve, benign prostatic hyperplasia was diagnosed. Despite the administration of α1-blockers, the patient's condition did not improve, and TUR-P was performed in accordance with his wish. 2 Outcome Pathological examination showed dense lymphoplasmacytic inflammation with no evidence of synchronous malignancy. On immunohistochemical staining, a large number (>40/high-power field) of IgG4-positive cells were observed in the lesions showing the inflammation, confirming the diagnosis of IgG4-related prostatitis. The patient's urinary function dramatically improved postoperatively, and good urinary function has been maintained for 3 years without additional treatment. 3 Conclusion Recognition of the impact of IgG4-related prostatitis on objective urinary function will help in appropriately treating patients with this condition.