Appendix Testis (Hydatid of Morgagni)

What is the appendix testis?

The appendix testis is a small piece of normal tissue attached to the upper portion of your testes (testicle).

People designated male at birth (DMAB) have a pair of testicles behind their penis. The two oval-shaped organs produce male hormones and sperm for reproduction. An appendix testis can be present on one testicle or both.

As an embryo grows into a fetus and then a baby, it has a Müllerian duct. In a person designated female at birth (DFAB), that duct develops into their female reproductive tract. In a person DMAB, the duct does not develop. The appendix testis is a remnant of the Müllerian duct, meaning that it’s a leftover part of something that previously existed.

The appendix testis is also called testicular appendix or hydatid of Morgagni.

Is testicular appendix normal?

An appendix testis is normal and common. It’s estimated to be present in about 80% of people designated male at birth.

Is appendix testis painful?

A testicular appendix has no purpose or function, and it’s not usually problematic. But it can get twisted and cause pain.

What is the purpose of a testicular appendix?

A testicular appendix serves no purpose. It’s a leftover piece of tissue from an embryo’s development.

Can an appendix testis be removed?

An appendix testis can be surgically removed. But there’s usually no need for surgery, even when the tissue gets twisted.

However, if you're having surgery in the same area for another reason, your surgeon might remove the testicular appendix. That will prevent any possibility of twisting in the future.

How big is a testicular appendix?

An appendix testis is small. It can range from 1 to 7 millimeters long.

Can you see an appendix testis?

A testicular appendix looks like a tiny fan or small glob of tissue. But it’s under your skin on the actual testes, so you can’t see it.

If an appendix of testis gets twisted and doesn’t receive enough blood, it may turn blue. That blue dot can sometimes be seen through your skin.

Is a testicular appendix hard?

A testicular appendix is a piece of normal human tissue, so it’s not usually hard. But if it gets twisted, it can become a hard, painful lump.

Can you feel an appendix testis?

Most people can’t feel a testicular appendix at all unless it gets twisted and causes pain.

What’s the difference between appendix testis and epididymal appendix?

Both the appendix testis and appendix epididymis are globs of tissue that may be found on your testicle. The appendix epididymis is a remnant of a different duct and is found behind your testicle. It occurs less often than appendix testis in about 30% of people with testes.

Neither serves any function, but both can twist and cause pain.

What is appendix testis torsion?

The only potential problem with the hydatid of Morgagni is torsion (twisting). It’s a common cause of testicular pain, especially between ages 7 and 12.

Appendix testis torsion can cause:

• Acute (sharp) pain on one testicle.
• A blue dot visible on the scrotum, due to blood loss to the piece of tissue.
• Redness.
• Swelling of the scrotum.

A healthcare provider can diagnose appendix testis torsion with a clinical exam and an ultrasound.

What’s the difference between testicular torsion and appendix testis torsion?

Testicular torsion occurs in the testicle itself (not the appendix testis). The spermatic cord, which provides blood flow to the testicle, becomes twisted and can cut off blood supply to the testicle. Testicular torsion is a medical emergency that must be treated to prevent testicle amputation.

How do you care for a torsed testicular appendix?

If you or your child is diagnosed with appendix testis torsion, treatment will involve:

• Bed rest.
• Ice.
• Nonsteroidal anti-inflammatory drugs (NSAIDs) for swelling and pain or analgesics for pain.
• Scrotal elevation (positioning to take pressure and weight off the scrotum and testicles).

Swelling and pain usually go away in about a week.

A healthcare provider may recommend surgery to explore the scrotum, but this is rare. They may consider scrotal exploration if the diagnosis is unclear or if the pain is:

• Severe.
• Long-lasting.
• Repetitive.
• Unrelieved by ice, rest and medication.

A note from Cleveland Clinic

An appendix testis is a normal piece of tissue on the testicle and is present in most people designated male at birth. Appendix testis torsion (twisting) is common between the ages of 7 to 12 years. It causes sharp pain that usually goes away with rest, ice and pain medication.