Descent of the Testis pp 45-67 | Cite as
Classification and Causes of Undescended Testes in Humans
Abstract
To understand the heterogeneous aetiology of cryptorchidism, a classification system is required. The classification is becoming clearer now that undescended testes (UDT) may be separated into congenital and ‘acquired’ types, and the recognition that ‘retractile’ testes form a grey zone between normally descended testes and those that may be developing to ascending, acquired UDT. Congenital UDT can be classified into intraabdominal UDT, canalicular, superficial inguinal pouch and prescrotal variants, aside from the rare ectopic testes. Acquired, ascending testes present later in childhood rather than at birth, and are thought to be caused by failure of the spermatic cord to elongate normally postnatally, so that the testis remains close to the inguinal canal as the scrotum grows away from the groin.The incidence of UDT was thought to be increasing but recent studies suggest this was just related to the use of different definitions of UDT. The aetiology remains mostly unknown, but is thought to be multifactorial. Genetic screening so far implicates muscle development and connective tissue remodelling in the aetiology.
Keywords
Inguinal Canal Undescended Testis Testicular Descent Patent Processus Vaginalis Nonpalpable TestisReferences
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