Introduction
This condition occurs only in boys for obvious reasons. Parents may notice that one or both testes may be missing from their normal location in the scrotum. This defect is usually present from birth, though maybe noticed as late as 3-4 years. The incidence of this defect in full-term boys is about
3%, but, in premature is as high a 30%. The reason is based on natural embryology in a boy. The testes are formed within the abdomen just below the developing kidneys. As the fetus grows, the testes descend down towards the groin or inguinal region around the 7th month. Around the 9th month, or, just before birth, they come out of the inguinal canal and descend down into the scrotum. Hence the very high incidence of non-descent of testes in pre-matures born at an 8-9th month.
In some boys, for many reasons both hormonal and/or mechanical, the testes on one or both sides may not descend normally into the scrotum. This results in absence of testis on one or both sides. The absent testis can be anywhere along the normal course of descent.
In those boys in whom a testis is not seen or felt on one or both sides, there are four basic possibilities and the goal is to find out which of these and treat it accordingly:
- Retractile testis
- Ectopic testis
- Undescended testis
- Absent testis
Retractile Testis
In these boys, the testis has come well down into the scrotum, to begin with. There is a muscle called Cremaster that surrounds the cord namely the vas deferens & blood vessels of the testis. In boys with a retractile testis, this muscle is overactive and oversensitive, a slight touch can cause it to contract and pull the testis upwards into the inguinal canal and disappear from the scrotum. Thus, when the parent is bathing the child, no testis may be seen or felt in the scrotum and the testis may remain up later too. A doctor examining the boy will be able to
gradually and manually massage the testis down into the scrotum and hold it there. This proves that the testis has descended normally and no further treatment is required. As the boy grows up and achieves puberty, the hormonal action on the testis will increase the weight, dimensions. Simultaneously, the cremaster becomes non-sensitive and the combined effect will allow the testis to come and stay within the scrotum.
Figure: No testis in the scrotum
Retractile testis
Figure: Testis can be brought down
Retractile testis
Ectopic Testis
In this condition, the testis is normal in all aspects and also descends normally till it reaches the inguinal canal from where, instead of going down into the scrotum, it goes into all abnormal directions - like behind the scrotum, in front of the root of the penis, the upper thigh, etc. as seen in the picture. Since this is an atypical position -this is called ectopic testis. This definitely requires a surgical operation to get the testis into the scrotum and fix it there.
Ectopic testis
Undescended Testis
In this condition, there is a halt in the normal process and the descent of the testis stops - these are cases of undescended testis. The point at which it stops may vary: in some, the testis comes into the inguinal canal, exits but stops short of entering the scrotum this is Emergent testis. In others, the testis enters the canal and then halts - called inguinal testis. In a few boys, the testis comes down up to the inguinal canal but stops before entering the canal in the abdomen - these are called abdominal testis. Rarer still are those testes that halt even higher up in the abdomen. The treatment will vary according to which position the testis is in. In the emergent and the inguinal testes, the examining doctor is able to feel the testis and hence they are called palpable undescended testes. In boys whose testes are in the abdomen and a few with those in the inguinal canal which cannot be felt by the doctor - are called nonpalpable undescended testes. All undescended testes require surgery to bring them don and fix them in the scrotum. The type of surgery may be open or Laparoscopic-assisted surgery.
Testis not in scrotum but in inguinal region
Absent Testis
This is a very rare condition and only 20% of all undescended testes are absent and nothing needs to be done after confirming the diagnosis. This is a diagnosis made after ruling out the other 3 possibilities.