The pathogenesis of cryptorchidism and splenogonadal fusion: a new hypothesis

To obtain new information about the pathogenesis of cryptorchidism.

Published reports of 111 males with splenogonadal fusion were examined and the presence and type of cryptorchidism and the degree of continuity between the spleen and gonads determined.

Of the 111 cases, 31% had cryptorchidism and of these 59% were bilaterally cryptorchid; 26% and 65% had right and left intra-abdominal testes, respectively. Of those with continuous splenogonadal fusion, 44% had cryptorchidism. Solely cryptorchid cases with splenogonadal fusion had reported bilateral absence of both legs, imperforate anus, spina bifida, diaphragmatic hernia and hypospadias.

An hypothesis is proposed that the abnormal development of the diaphragmatic ligaments of the testes may lead to lack of their involution, with consequent cryptorchidism. In the case of splenogonadal fusion, the abnormal ligaments are colonized by splenic cells, possibly because of an abnormal proximity to the splenic anlage, with the resulting abnormal ligament persisting as the splenic cord and thus resulting in cryptorchidism. The basic abnormality may be in the connections of the diaphragmatic ligaments, caused by abnormal midline development in the third to fourth week of gestation.