# Pathology

Pathology

The condition is more common on the right and is bilateral in 20% of cases. In adults, secondary sexual characteristics are typically normal. The testis may be: /uni25CF intra-abdominal; usually extraperitoneal just inside the internal inguinal ring; /uni25CF within the inguinal canal; it may not be palpable ( Figure 86.2 ); /uni25CF extracanalicular; usually at the scrotal neck (high scrotal); 

Superficial ectopic
Femoral
Normal
Figure 86.1
The path of descent of the testis from the
abdomen (retroperitoneal) down the inguinal canal to
the scrotum. Descent can be arrested at any stage with
the majority in the high scrotal area. Rarely, the testis
occupies a more ectopic position outside the normal
path of descent (courtesy of Dr Mohan Gundeti).

/uni25CF ectopic; an ectopic testis is one that has ended up away from the normal path of descent. The commonest site is the superficial inguinal pouch, just inferior and medial to the superficial inguinal ring. Other rarer ectopic sites include the femoral triangle, root of  the penis and perineum. Incompletely descended testes are often macroscopically normal in early childhood, but by puberty the testis is typically smaller than its intrascrotal counterpart. Microscopic changes are apparent from 1–2 years, including loss of  Ley dig cells, degeneration of  Sertoli cells and decreased spermatogenesis. The higher the testis, the greater the degree of  histological change. 

Figure 86.2
Undescended testes in a boy aged 12 years. Note the
bilateral undescended testes with the underdeveloped scrotum. In
cases of retractile testis, the scrotum is relatively well developed.