Undescended testis

English: The route of the vas deferens from te...

English: The route of the vas deferens from testis to the penis. (Photo credit: Wikipedia)


Incomplete descent of testis occurs when testis is arrested in some part of its normal path to scrotum.

Development and descent of testis

Testis develops from genital ridge in 7th week of intrauterine life, in the retroperitoneum below the kidneys at around 10th thoracic level.It gets covered by processus vaginalis which is a fold of peritoneum which aids in theĀ  descent of testis into the scrotum.
By the 3rd month testis lies at the level of internal inguinal ring, and up to 7th month it stays there, descent of testis into scrotum occurs between 7 to 9th month of intrauterine life.
The testis is supplied by testicular arteries which arises from abdominal aorta below renal arteries. Left testicular vein drains into left renal vein and right vein drains into IVC.


4% boys are born with undescended testis.In 2/3rd of these cases descent occurs by 3rd month. The incidence of UDT by 1 year of age is 1%.If descent does not occur by 3 months it is unlikely to descent.

Undescended testis is more common in the right side. Bilateral UDT is seen in 20%.
Sites of UDT are
1.Intra abdominal – Lying extra peritoneally just inside internal inguinal ring
2.Intracanalicular- May or may not be palpable.
3.Extracanalicular- At neck of scrotum
Ectopic testis may be seen in sites other than the line of descent of testis. MC site is superficial inguinal pouch.It can also be found in femoral triangle, root of penis, perineum.

Though undescended testia has the same size in childhood compared to the descended testis, UDT gets atrophied by puberty.

Histological changes occuring in UDT are

1.Loss of leydig cells
Degeneration of sertoli cells
Decreased spermatogenesis
These changes start to occur from 1st year.
2.Malignancy – 5-10 times greater chance compared to normal.Seminoma is the mc variety of cancer
3.Hernia – 90% UDT have patent processus vaginalis
4.Testicular torsion


Treatment of UDT is mainly surgical. procedure is done before 1 year so that fertility can be preserved.
1.Palpable testis – Testis mobilised and processus vaginalis ligated and divided and orchodopexy is done with placement of testis in subdartos pouch.
2.Impalpabe testia- Testis is localised by USG if Intracanalicular or by laparoscopy if intraabdominal.

If there is insufficient length of cord, lengthening of cord can be done by
1.Ligating and dividing processus vaginalis.
2.Coverings of spermatic cord including cremasteric muscles is divided
3.Lateral fibrous bands inside the internal ring should be divided.

If sufficient length cannot be obtained even after performing these steps, orchiopexy can be done as a 2 stage procedure.

1.Testis mobilised as far as possible and is anchored with suture and mobilisation is completed after 6 months.
2.An alternative approach involves initial division of gonadal artery( it is tighter than the vas) so that the testis become dependant on vasal artery for its blood supply. The second stage involves conventional orchiopexy

Orchidectomy should be considered in atrophic testis, if the other testis is found to be normal in a post pubertal boy.

  1. i am preparing for exams this year. was very happy to see you blogging again

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