[A Case of IgG4-Related Disease Arising in Female Periurethra].

A 67-year-old female, with a past medical history of IgG4-related Mikulicz disease, was referred to our department for a periurethral mass revealed by contrast-enhanced computed tomography. She presented with weak urine flow a half year before the first consultation. Magnetic resonance imaging (MRI) revealed a periurethral mass, 39×39×29 mm, extending from the bladder neck to the urethral meatus. Serum IgG4 level was elevated to 580 mg/dl. Histological examination by the transvasinal biopsy revealed a lymphocytic infiltrate with IgG4-positive plasmacytoid predominance, leading to the diagnosis of IgG4-related disease arising in the periurethra. She was treated with prednisolone for 4 months, and urinary disturbance disappeared. MRI showed that the periurethral mass decreased in size.