Ganglioneuromas in the adult scrotum

Reporting on a patient with paratesticular ganglioneuromas Mr Hanna and his colleagues (February 2005 JRSM¹) recommend imaging of the retroperitoneum in such cases because of the common embryological origin of scrotum and retroperitoneum. We disagree with their embryology. The scrotum develops as follows: between the sixth and eighth weeks of development, a pair of swellings (cloacal folds) appear on either side of the cloacal membrane. The folds meet anterior to this membrane to form the genital tubercle.² The peritoneum divides the cloacal membrane into a urogenital membrane and an anal membrane. This also separates the cloacal fold into a urethral fold and an anal fold. Then, a pair of labia-scrotal swellings appear, which ultimately develop into a male scrotum.³ By contrast, the ganglionic crest will be constituted, in the mesoblast space, from the ectoblast, from each side of the neural tube on the whole length of the notochord, as metamerized bands to give the matrix of the sympathetic (from which paratesticular ganglioneuromas arise) and parasympathetic nervous system.