What is the Difference Between Undescended Testis and Ectopic Testis

Undescended testis and ectopic testis are two types of cryptorchidism. In normal embryological development, the testis descends from the abdomen to the scrotum. However, this process is incomplete in the context of cryptorchidism. It can be defined broadly into three conditions: undescended testis, ectopic testis, and ascending testis.

The key difference between undescended testis and ectopic testis is their cause. Undescended testis is a condition where the testis is absent from the scrotum but lies along the line of testicular descent, while ectopic testis is a condition where the testis is found away from the normal path of descent.

CONTENTS

1. Overview and Key Difference
2. What is Undescended Testis 
3. What is Ectopic Testis
4. Similarities – Undescended Testis and Ectopic Testis
5. Undescended Testis vs Ectopic Testis in Tabular Form
6. Summary – Undescended Testis vs Ectopic Testis
7. FAQ – Undescended Testis and Ectopic Testis

What is Undescended Testis?

Undescended testis is a condition where a testicle doesn’t move down into its proper place in the scrotum. This condition sometimes affects both testicles. Not seeing or feeling a testicle in the scrotum is the main symptom of this condition. Genes, the health of the mother of the baby, and other factors might have a combined effect on causing undescended testicles.

Figure 01: Normal vs Undescended Testis

Undescended testis can be diagnosed through physical examination, laparoscopy, and open surgery. Furthermore, treatment options for undescended testis mainly include a surgery called orchiopexy and hormone therapy, such as giving human chorionic gonadotropin and testicular prostheses.

What is Ectopic Testis?

An ectopic testis is a condition where the testis has deviated from the normal path of testicular descent and may be found in almost any other region. Ectopic testis does not show any symptoms; the only sign is the absence of one or both testicles, which is immediately noticeable in the baby due to their empty scrotal sac. Moreover, ectopic testis is caused by congenital endocrine abnormalities during pregnancy.

Figure 02: Surgery for Ectopic Testis

Ectopic testis can be diagnosed through physical examination and ultrasound. Furthermore, treatment options for ectopic testis include laparoscopic surgery to place the testicle in the scrotum.

Similarities Between Undescended Testis and Ectopic Testis

1. Undescended testis and ectopic testis are two types of cryptorchidism.
2. Both conditions do not show many symptoms.
3. These conditions may carry the risk of infertility.
4. Both these conditions may cause complications such as testicular torsion, inguinal hernia, and impaired fertility.
5. Both these conditions can be diagnosed through physical examination and imaging tests.
6. They are mainly treated through surgeries.

Difference Between Undescended Testis and Ectopic Testis

Definition

1. Undescended testis is a condition that refers to the absence of one or both testis in the scrotum at birth but lies along the line of testicular descent.
2. Ectopic testis refers to a condition in which the testis is located in an abnormal position outside the scrotum, which is characterized by the testis being situated outside of its normal descent.

Location of Testis

1. In undescended testis, testis is located in the abdomen or inguinal canal.
2. In ectopic testis, testis is located in the groin, perineum, or even the opposite scrotum.

Commonness

1. Undescended testis is more common.
2. Ectopic testis is less common.

Causes

1. Undescended testis is caused by genes, the health of the mother of the baby, and other factors like premature birth, low birth weight, and certain hormonal abnormalities.
2. Ectopic testis is caused by congenital endocrine abnormalities during pregnancy.

Descent Process

1. In undescended testis, the testis is partially descended but unable to reach the scrotum.
2. In ectopic testis, the testis does not follow the normal descent process at all.

Symptoms

1. In undescended testis, the testicle is not visible or palpable in the scrotum but is present along the normal descent line in imaging tests.
2. In ectopic testis, imaging tests reveal the absence of the testis in the scrotum, located away from the normal path of descent.

Infertility

1. Undescended testis has a higher risk of infertility.
2. Ectopic testis has a less risk of fertility.

Diagnosis

1. Undescended testis can be diagnosed by physical examination, laparoscopy, and open surgery.
2. Ectopic testis can be diagnosed by physical examination and ultrasound.

Treatment

1. Undescended testis can be treated by orchiopexy, hormone therapy, such as giving human chorionic gonadotropin and testicular prostheses.
2. Ectopic testis can be treated by laparoscopic surgery to place the testicle in the scrotum.

The following table summarizes the difference between undescended testis and ectopic testis.

Summary – Undescended Testis vs Ectopic Testis

Undescended testis and ectopic testis are two types of cryptorchidism. Undescended testis is a condition where a testis is absent from the scrotum but lies along the line of testicular descent, while ectopic testis is a condition where a testis is ectopic and is in a location outside the scrotum’s normal path of descent. Furthermore, in undescended testis, the testis can be found in the abdomen or inguinal canal, whereas in ectopic testis, the testis can be found in the groin, perineum, or even the opposite scrotum. This summarizes the difference between undescended testis and ectopic testis.

FAQ: Undescended Testis and Ectopic Testis

1. What causes a child to have one undescended testicle?

• The exact causes of undescended testicles are not known. Premature birth plays a role, but it may also be genetic. Moreover, there is a 7.5% chance for a brother of a boy with undescended testicles to have the same condition. In addition, other risk factors include low birth weight and certain hormonal abnormalities.

2. What is the diagnosis of undescended testis?

• A pelvic ultrasound can determine the exact location of an undescended testicle, specially if this condition is not easily felt or palpable. In this imaging test, the doctor places a device called a transducer on the baby’s groin and abdomen.

3. How do you fix an undescended testicle?

• In most cases, a simple orchidopexy can be performed to correct undescended testicle. This involves first making a cut in the groin to locate the undescended testicle. Then this testicle is moved downwards and repositioned in the scrotum through a second incision.

4. What are the ectopic sites for testis?

• The common sites for ectopic testes may include the superficial inguinal pouch, groin, perineum, opposite side of the scrotum, femoral canal, and pubopenile region. In addition to these sites, preperitoneal and extracorporeal ectopic testes also have been reported.

5. How do you treat testicular ectopia?

• Standard treatment for ectopic testis is mainly surgery, including inguinal hernia repair, transseptal orchiopexy, and the repair of congenital anomalies. Moreover, hormone therapy won’t work for ectopic testis.

Reference:

1. “Ectopic Testis.” ScienceDirect.
2. “Undescended Testicle.” Mayo Clinic, Mayo Foundation for Medical Education and Research.

Image Courtesy:

1. “Scrotal ultrasonography of undescended testis” By Chee-Wai Mak and Wen-Sheng Tzeng – (2012). “Sonography of the Scrotum”.  DOI:10.5772/27586. from Kerry Thoirs. Sonography. ISBN 978-953-307-947-9, Published (CC BY 3.0) via Commons Wikimedia

2. “Image from page 468 of “The practice of surgery” (1910)” By Internet Archive Book Images (Public Domain) via Flickr

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