Klinefelter syndrome is a clinical syndrome with a distinct 47, XXY karyotype. Patients are characterized by a tall eunuchoid stature, small testes, hypergonotrophic hypogonadism, gynecomastia, learning difficulties and infertility. These patients have also been found to have raised estrogen levels. We report a 16 year old boy with Klinefelter syndrome presenting to our institution with gross hematuria. Cystoscopy and biopsy revealed the diagnosis of pseudomembranous trigonitis. Immunohistochemical stains showed an increase in estrogen and progesterone receptors in the trigone area but not in the rest of the bladder. In view of the patient's mildly raised estrogen levels and the histological findings, we postulate that estrogen is the driver of the development of pseudomembranous trigonitis. This is the first reported case of pseudomembranous trigonitis seen in association with Klinefelter syndrome, and also the first case of pseudomembranous trigonitis occurring within the male adolescent age group.
Keywords: Klinefelter syndrome; pediatric; pseudomembranous trigonitis.