The Common Vein Copyright 2010
Introduction
The prostate is derived from the urogenital sinus. The prostate develops as 30-50 distinct glands which grow in confluence and gradually fuse. These tubuloalveolar glands originate from the uroepithelium and grow into the surrounding wall of the developing urethra and enlarge. After birth, the size of the prostate remains relatively unchanged for 10-12 years, until puberty. Increased production of androgens stimulates an increase in gland size.
The Prostate will attain a mass of approximately 20 grams by the end of puberty, which will again remain stable for several decades.
The prostate first appears during the third month of embryonic development. Five epithelial buds form in a paired manner on the posterior side of the urogenital sinus on both sides of the verumontanum, and they then invade the mesenchyme to form the prostate. The top pairs of buds form the inner zone of the prostate and appear to be of mesodermal origin; the lower buds form the outer zone of the prostate and appear to be of endodermal origin. This is of potential importance since the inner zone gives rise to benign prostatic hyperplasia (BPH) tissue, whereas the outer zone contains the primary origin of cancer. Much of the development, growth, invasion, budding, and branching are controlled by homeobox genes as well as dihydrotestosterone, which is produced from testosterone in the urogenital sinus. By its 4th month, the fetal prostate is well-developed.
Developmental abnormalities
Developmental abnormalities are rare. Aplasia and hypoplasia represent incomplete development. This is usually due to a deficiency of androgen production. Cystic changes may occur proximally or distally or in neighboring structures. These changes may lead to infertility but are otherwise asymptomatic. Mesonephric remnants represent incomplete obliteration of these pimordial embryologic structures.