Gliding testis is a wonderful name given to high scrotal testis, the mildest form of a true undescended testicle. They get their name because the testicle is located just above the scrotum and unlike most undescended testicles can be manipulated down to the upper scrotum, but “glides” back up inside the boy.
They are difficult to tell apart from retractile testicles like I had but it’s important to distinguish them, as the gliding testicle undergoes non-reversible damage by the age of 7, while retractile testicles remain healthy. This means gliding testicles need surgery, while retractile testicles are fine with careful monitoring.
The distinction is that while both testicles can be brought into the scrotum, the gliding testicle reascends as soon as you let go, while the retractile testicle stays until the muscle it’s attached to (the cremaster muscle) contracts again. That’s the theory, in practice it is much more difficult! Often even the best consultant cannot tell until the boy has been taken into the operating theatre and given a general anaesthetic (my surgeon did this), as complete relaxation of the cremasteric muscle by general anaesthesia and/or muscular relaxants is helpful in determining a retractile from an undescended or gliding testis.
Two anatomical findings are typical of the gliding testis: the absence of the gubernaculum and a processus vaginalis partially patent from the upper scrotum to the mid groin area. This feature explains the mobility of the gliding testis from the external ring to the upper scrotum. The absence of the gubernaculum may be responsible for a higher incidence of spermatic cord torsion in this population. The gliding testis is a distinct entity, representing the mildest degree of a true undescended testis. As hormonal treatment gives only transient results, orchidopexy should be considered before testicular damage occurs.
Until recently high scrotal testicles were treated as a different type of undescended testicle, but recent research suggests they should be regarded as a part of the spectrum of either congenital-undescended testis or acquired-undescended testis. Since spontaneous descent can occur at puberty in acquired-high scrotal testis, treatment may be different, though surgery is often recommended.