What Are TARTs in Classic CAH? How Are They Monitored?

Testicular Adrenal Rest Tumors (TARTs) are benign (non-cancerous) growths that can develop in the testicles of males with classic congenital adrenal hyperplasia (CAH) ^[1]. Because early tumors often cannot be felt during a physical exam, they are monitored using routine testicular ultrasounds ^[2]. Screening usually begins in childhood (often around age 8 to 10) or at the onset of puberty, and continues annually, though the exact schedule depends on your child’s specific risk factors and hormonal control ^[3][4].

Why Do TARTs Develop?

TARTs are made of adrenal-like cells that reside within the testicles ^[5]. In CAH, the body’s hormone feedback system is abnormal. When the body senses low cortisol, the pituitary gland in the brain releases high levels of ACTH (adrenocorticotropic hormone) to stimulate the adrenal glands ^[4]. This chronic ACTH stimulation also encourages the adrenal-like cells in the testicles to grow and form tumors ^[4][6].

It is important to know that managing CAH is complex, and TARTs can sometimes develop even when you are doing your best to follow the treatment plan. However, boys with the severe salt-wasting form of CAH, or those with consistently elevated ACTH and androgen markers over time, generally have a higher risk of developing TARTs ^[4][7].

Safety Note: While TARTs are benign, not every testicular lump is a TART. Any new testicular mass, rapid enlargement, or sudden severe pain requires immediate medical evaluation to rule out other serious conditions like testicular cancer or testicular torsion.

How Do TARTs Affect Fertility?

TARTs typically grow in the center of the testicle (the rete testis), an area that helps transport sperm from the tiny tubes where they are produced ^[8][9]. If TARTs grow too large, their physical presence can compress these structures, causing scarring (fibrosis) and interfering with normal sperm production ^[10].

If left unmanaged, this pressure can damage the testicular tissue and severely reduce sperm count (oligospermia) or lead to a complete lack of sperm in the semen (azoospermia) ^[8][11]. Catching and managing TARTs early may help reduce the risk of permanent testicular damage, though fertility outcomes can vary from person to person ^[10].

When and How Should Screening Begin?

Because small TARTs are hidden inside the testicle, the preferred noninvasive way to monitor for them is through a painless scrotal ultrasound, which uses sound waves and involves no radiation ^[9].

• When to start: Current endocrine guidelines advise starting routine ultrasound screening at the onset of puberty ^[3]. However, some studies show TARTs can develop much earlier—one study found that 22% of tumors in their specific patient group appeared before age 10 ^[4]. Because of this, many specialists recommend an individualized approach, often starting screening in childhood (around age 8 to 10) for boys with salt-wasting CAH, advanced bone age, or a history of high ACTH levels ^[4][7].
• How often to screen: Testicular ultrasounds are typically repeated once a year ^[3]. If a TART is found, or if hormone levels are difficult to manage, your endocrinologist may recommend more frequent monitoring, such as every 6 months ^[12][4].

What Happens if a TART is Found?

If an ultrasound detects a TART, the first step is usually to review your son’s CAH medication and recent lab results with his endocrinologist ^[13]. Sometimes, optimizing the glucocorticoid dose lowers the ACTH levels, which can cause the tumor to shrink ^[13]. Never adjust your child’s medication without your endocrinologist’s guidance, as too much steroid medication carries its own significant health risks ^[13].

Surgery is rarely needed for TARTs and is generally avoided unless the tumor causes severe pain or cannot be distinguished from cancer ^[14][15]. As your son gets older and transitions into adolescence and adulthood, his care team—which may eventually include a urologist or fertility specialist—will likely discuss semen analysis (a test to check sperm health) and freezing sperm (cryopreservation) to help preserve his options for having biological children in the future ^[3][11].