Can TARTs Affect Fertility in Boys With Classic CAH?

Testicular Adrenal Rest Tumors (TARTs) are benign (non-cancerous) masses of tissue in the testicles that resemble the tissue of the adrenal glands ^[1]. They are a known complication for males with classic Congenital Adrenal Hyperplasia (CAH). While TARTs are not cancer, as they grow they can press on the structures inside the testicles that produce and transport sperm ^[2]. This compression increases the risk of impaired fertility, particularly if the tumors become large or are present in both testicles ^[3].

However, having a TART does not mean your son will inevitably become infertile. Early detection through regular, painless ultrasound screening allows your endocrinologist to adjust medications if needed ^[4]. While careful management can often protect testicular function, it is also important to remember that male fertility in CAH can be influenced by overall hormonal balance and prolonged steroid exposure, even without TARTs ^[5].

What Are TARTs?

During early fetal development, the adrenal glands and testicles form close to one another. Occasionally, tiny clusters (or “rests”) of adrenal-like cells settle inside the testicles ^[1]. In males with CAH, the pituitary gland often produces high levels of ACTH (Adrenocorticotropic Hormone) to stimulate the underactive adrenal glands. Because TARTs are made of similar tissue, this excess ACTH can also stimulate these rests in the testicles to grow ^[6].

TARTs most commonly become detectable during or after puberty. However, they can sometimes appear in earlier childhood, especially in boys who have the salt-wasting form of classic CAH (a severe form requiring both glucocorticoid and mineralocorticoid replacement) or those whose CAH hormone levels are difficult to balance ^[6].

When to Seek Immediate Care
While TARTs are “almost always benign,” you should never assume a new symptom is just a TART. Sudden, severe scrotal pain is a medical emergency that could indicate testicular torsion (a twisted testicle). Any new lump, rapid swelling, or persistent pain must be evaluated promptly by a doctor to rule out other serious conditions, including testicular cancer ^[7].

How TARTs Affect Fertility

TARTs usually grow near the center of the testicle. If they become large, they can compress critical reproductive structures ^[2]:

• Seminiferous tubules: The tightly coiled tubes where sperm is produced.
• Rete testis: The network of tubes that carries sperm out of the testicle.

Over time, this pressure can reduce sperm production or physically block sperm from leaving the testicle. Prolonged compression may lead to fibrosis (scarring) and irreversible tissue damage ^[2].

Studies of adult men with classic CAH show that significant reductions in sperm count (oligospermia) or a complete absence of sperm in the semen (azoospermia) are more common in men who have TARTs ^[3]. The risk is highest with large, long-standing tumors in both testicles ^[3].

Ultrasound Screening

Because TARTs are often painless and too small to be felt during a physical exam (impalpable), scrotal ultrasound is the best way to detect them early ^[4]. An ultrasound is a painless imaging test that uses sound waves and does not involve radiation.

• When to screen: Guidelines (such as those from the Endocrine Society) suggest that regular scrotal ultrasounds should generally begin when a boy enters puberty ^[4].
• Individualized schedules: Your doctor may recommend starting earlier (sometimes before age 10) based on your son’s pubertal status, prior exams, or if his hormone levels have been difficult to balance ^[6].
• Expert review: Ultrasounds should be reviewed by a radiologist or urologist familiar with CAH. TARTs typically appear on both sides and look a specific way on ultrasound, which helps distinguish them from other tumors ^[7].

What Happens if a TART is Found?

If an ultrasound detects a TART, the diagnosis and follow-up plan will be managed by your clinical team. The steps often include:

Medication Adjustments

Your endocrinologist will review your son’s medications. Glucocorticoids (like hydrocortisone) are used to replace missing cortisol and suppress excess ACTH, while mineralocorticoids (like fludrocortisone) help the body retain salt and water ^[8].

Sometimes, optimizing the hydrocortisone dose can lower ACTH levels enough to shrink the TART and allow sperm production to recover ^[9]. However, this is a delicate balance. Doctors will not try to completely normalize ACTH or 17-OHP if it means prescribing dangerously high doses of steroids, which can cause stunted growth, weight gain, and bone issues ^[10]. Never adjust or stop your son’s CAH medications without consulting your endocrinologist.

Monitoring and Surgery

The care team will monitor the size of the TART over time. Surgery to remove TARTs (testis-sparing surgery) is not an automatic next step. It is generally reserved for rare cases where tumors cause severe pain, do not respond to medication, or if the doctor is uncertain whether the mass is a TART or something more dangerous ^[9]. Surgery is used cautiously because cutting into the testicle can itself damage healthy tissue and impair fertility.

Fertility Preservation

For adolescents and young men who have passed puberty and can provide a sample, seeing a reproductive urologist is recommended ^[5].

• Semen Analysis: A test to check sperm count. Because sperm production can fluctuate, repeat testing might be needed.
• Sperm Cryopreservation (Freezing): If ejaculated sperm is present, freezing it is a proven way to safeguard future fertility ^[4].
• Pre-pubertal boys: Routine sperm freezing is not an option before puberty, and experimental tissue-freezing techniques are usually only discussed in specialized settings.
• Advanced cases: If a TART has caused a permanent blockage (obstructive azoospermia), a specialist may discuss advanced techniques like extracting sperm directly from the testicles (TESE) for use in in-vitro fertilization (IVF) ^[9].