An unusual subset of cryptorchidism: possible end organ failure

A paucity of germ cells exists in the cryptorchid gonad that usually correlates with a similar finding in the contralateral descended testis. However, we have noted a small number of boys with cryptorchidism in whom there is a significant difference between the histological evaluation of the cryptorchid testis and the normal descended testis that may indicate a different etiology.

From 1986 to 1991, 1,426 boys with unilateral cryptorchidism underwent orchiopexy, of whom 752 also underwent bilateral testicular biopsy. Testicular volume and position, and patency of the processus vaginalis were examined. Biopsies were fixed in 2% glutaraldehyde and embedded in Epon. Semithin tissue sections were analyzed by 2 independent investigators. The number of total germ cells, gonocytes, adult dark and pale spermatogonia, primary spermatocytes and Leydig cells was assessed.

Of the 1,426 boys the undescended testis was on the right side in 726 and on the left side in 658 (52 versus 48%, p = 0068). Of the 752 boys who underwent bilateral biopsy 42 (5.6%) 1.1 to 16 years old (mean age plus or minus standard deviation 0 5.2 +/- 3.65) had a poor fertility index of less than 0.2 germ cell per tubule in the cryptorchid gonad, although the germ cell count in the descended testis was normal. Of the 42 testes in this special group of boys 30 (71%) were on the right side (Fisher's exact test p <0.23), including 16 (38%) in an intra-abdominal or high canalicular position. The processus vaginalis was patent in 86% of the intra-abdominal testes and in 100% of those located at the tubercle but in only 25% of those in a pre-scrotal position. While average germ cell count in the cryptorchid testis was 0.06 per tubule with abnormal germ cell maturation, number was normal (greater than 2 germ cells per tubule) in the contralateral descended testis with a normal distribution of adult dark and pale spermatogonia, and primary spermatocytes. Average volume of the cryptorchid testis was significantly less than that of the descended testis (1.20 +/- 0.35 versus 1.60 +/- 0.68 mm.3, p <0.0001).

Based on the normal scrotal testis the fertility prognosis is good in this small subgroup of boys with cryptorchidism. Rather than the usual endocrinopathy of cryptorchidism, the undescended testis in these boys may be the result of end organ failure. These patients with favorable fertility potential may be recognized only if each testis is biopsied at unilateral orchiopexy.