What conditions are commonly associated with unilateral undescended testis (cryptorchidism) and absent scrotum on the affected side?

Inguinal Hernia is the Most Common Associated Condition

In a patient with unilateral undescended testis and absent scrotum on the affected side, inguinal hernia is the most commonly associated condition, followed by hypospadias as part of testicular dysgenesis syndrome. 1

Primary Associated Conditions

Inguinal Hernia (Answer B)

• Inguinal hernia is one of the two most common anomalies associated with undescended testis, occurring due to the persistent patent processus vaginalis that accompanies testicular maldescent 1
• The anatomical connection is direct: the same embryological defect that prevents testicular descent often leaves the processus vaginalis patent, creating a pathway for herniation 1
• This association is so common that surgeons performing orchiopexy routinely explore for and repair concurrent inguinal hernias 1

Hypospadias (Answer A)

• Hypospadias is the other most common associated anomaly with undescended testis, particularly when both conditions coexist, suggesting testicular dysgenesis syndrome 2, 1
• The combination of cryptorchidism with hypospadias indicates a more severe underlying disorder of gonadal development rather than isolated cryptorchidism 3
• When unilateral cryptorchidism presents with hypospadias and nonpalpable testis, the risk of an intersex condition increases 3-fold compared to palpable undescended testis (50% vs 15%) 4
• Testicular dysgenesis syndrome specifically encompasses cryptorchidism, hypospadias, lower fertility, higher malignancy risk, and Leydig/Sertoli cell dysfunction 3

Conditions NOT Typically Associated

Pyloric Stenosis (Answer C)

• Pyloric stenosis is not recognized as an associated condition with cryptorchidism in any of the major guidelines or research evidence 2, 3, 1
• This is a separate gastrointestinal developmental anomaly without shared embryological pathways with testicular descent

Congenital Heart Disease (Answer D)

• Congenital heart disease is not listed among the associated anomalies with undescended testis in guideline recommendations 2, 3, 1
• While genitourinary anomalies may occasionally coexist with cardiac defects in syndromic conditions, this is not a characteristic association with isolated cryptorchidism

Additional Important Associations to Consider

Genitourinary Anomalies

• Renal anomalies occur in 3.2-4% of cases, including duplication of upper urinary tract, hydronephrosis, polycystic kidney, horseshoe kidney, and renal agenesis 5
• Congenital unilateral absence of vas deferens with ipsilateral renal agenesis represents a rare but recognized association 6
• Posterior urethral valves and prune belly syndrome occur in approximately 0.4% of cases 5

Disorders of Sexual Development

• The combination of unilateral/bilateral cryptorchidism with phallic anomalies (hypospadias or micropenis) should prompt evaluation for disorders of sexual development 2
• A newborn with bilateral nonpalpable gonads and male phallus is potentially a genetic female (46,XX) with congenital adrenal hyperplasia until proven otherwise 2

Clinical Approach Algorithm

For unilateral undescended testis with absent hemiscrotum:

1. Examine for inguinal hernia - palpate the inguinal canal for reducible mass, assess for bowel sounds in scrotum 1

2. Inspect the penis carefully - document meatal position to identify hypospadias, assess for chordee, measure penile length 2, 3

3. Determine testicular palpability - this stratifies intersex risk if hypospadias is present (nonpalpable = 50% intersex risk vs palpable = 15% risk) 4

4. Perform renal ultrasound - recommended in all cases to identify associated upper tract anomalies, particularly if vas deferens abnormalities are suspected 6, 5

5. Consider karyotype and hormonal evaluation if hypospadias coexists, especially with nonpalpable testis or posterior hypospadias 2, 4

Critical Pitfalls

• Do not perform ultrasound to locate the undescended testis itself - this rarely assists in surgical decision-making, as more than 70% are palpable by experienced examination and nonpalpable testes require surgical exploration regardless 2
• Do not dismiss the combination of cryptorchidism with hypospadias as coincidental - this represents testicular dysgenesis syndrome requiring comprehensive evaluation for intersex conditions 3, 4
• Do not delay surgical referral beyond 18 months of age - orchiopexy should be performed by this age to maximize fertility potential and reduce cancer risk 3