Ectopic prostate tissue within the processus vaginalis: insights into prostate embryogenesis.

We report an 11-year-old boy who presented with a scrotal mass superior to the epididymis in the processus vaginalis. The mass consisted of prostate tissue, including glands and fibromuscular stroma, communicating with a spermatocele. Strong immunostaining for prostate-specific antigen was seen in the glandular epithelium. Immunostaining for peanut agglutinin highlighted the luminal plasma membrane in a subset of epithelial cells, mainly those located around the periphery of the nodule. To the best of our knowledge, this represents the first report of a pediatric patient with ectopic prostate tissue located outside the urinary tract and the first instance altogether of ectopic prostate noted at this location. The young age of the patient, the lesion's constituents, and its location suggest that the finding represents a disorder of development.