What causes cryptorchidism?

Currently, the precise mechanisms underlying cryptorchidism remain incompletely understood. The etiology of cryptorchidism can be broadly categorized as follows:

First, the endocrine theory: Disruption of the hypothalamic-pituitary-testicular axis, abnormal testicular differentiation, and deficiencies in androgens or anti-Müllerian hormone (AMH) can all contribute to cryptorchidism.

Second, genetic factors: Some patients exhibit familial cryptorchidism. Additionally, abnormalities of autosomes or sex chromosomes may also lead to cryptorchidism.Third, anatomical factors: These include absence of the gubernaculum testis—a critical structure that guides testicular descent from the abdominal cavity into the scrotum. When the gubernaculum fails to function properly, cryptorchidism may result.

Other anatomical contributors include failure of closure of the processus vaginalis, abnormal inguinal development (e.g., an excessively narrow internal inguinal ring or mechanical obstruction at the scrotal opening), and abnormally short spermatic vessels or vas deferens.

Intrinsic testicular developmental defects also constitute a cause. In certain cases, intrinsic testicular abnormalities—such as intrauterine testicular torsion followed by atrophy, resulting in only residual spermatic vessels and vas deferens; separation of the testis from the epididymis; or congenital absence of the epididymis—may impair normal testicular descent.