Embryology, Anatomy, and Congenital Anomalies of the Prostate and Seminal Vesicles

Abstract

The prostate, seminal vesicles (SVs), and bulbourethral (Cowper’s) glands develop near the junction between the mesonephric ducts and the pelvic urethra. The prostate gland and Cowper’s gland develop from the urogenital sinus whereas the SV, vas deferens (VD), ejaculatory duct (ED), and epididymis originate from the mesonephric (wolffian) ducts. The SV develops as bulbous swelling of the distal mesonephric duct at 10–12 weeks’ gestation, shortly before the onset of prostatic development. The mesonephric duct later becomes the vasa deferentia (VDs). As the ureteric bud also arises from the mesonephric duct in earlier fetal life (fifth gestational week), the development of the SV and VD is closely related to the development of the kidney and ureter (Fig. 113.1). Any alteration occurring during ureteric bud development may affect the formation of the SV or VD. If the ureteric bud arises from a more proximal portion of the mesonephric duct, it fails to blend with the metanephric blastema and renal agenesis or dysgenesis will develop (Sandlow et al. 2007). When this happens, ectopic ureteral insertion into the posterior urethra, SV, VD, or ED may occur (Gordon and Kessler 1972). The prostatic budding begins in the tenthweek and the prostatic outgrowths are induced by surrounding mesenchyme and hormonal effect (Schoenwolf et al. 2009). As the prostate develops, Cowper’s glands sprout from the urethra just inferior to the prostate (Fig. 113.2). By 13–15 weeks, the prostate begins its secretary activity.