Associated Conditions with Unilateral Undescended Testis
Inguinal hernia is the most common associated condition with unilateral undescended testis, making option B the correct answer.
Primary Association: Inguinal Hernia
Inguinal hernias are the most frequently associated anomaly with undescended testis, particularly in unilateral cases. 1 This association occurs because both conditions share a common embryological mechanism involving the processus vaginalis:
- During testicular descent (25-35 weeks gestation), the testis draws an extension of the peritoneal lining through the inguinal canal, creating the processus vaginalis 2
- Incomplete involution of the processus vaginalis creates a patent processus vaginalis (PPV), through which intra-abdominal structures can herniate 2
- The prevalence of PPV is highest during infancy, with rates as high as 80% in term male infants, though this declines with age 2
- The relationship between the processus vaginalis and testicular descent explains why more than 90% of pediatric inguinal hernias occur in boys 2
Why Hypospadias is NOT Specifically Associated with Unilateral Cases
While hypospadias can occur with cryptorchidism, this association is part of testicular dysgenesis syndrome (TDS) and is not specifically linked to whether the undescended testis is unilateral or bilateral 2:
- TDS is a developmental disorder caused by environmental and/or genetic influences early in pregnancy 2
- TDS includes cryptorchidism, hypospadias, lower fertility, higher risk of malignancy, and dysfunction of Leydig/Sertoli cells 2
- When cryptorchidism is present with phallic anomalies like hypospadias, evaluation for disorders of sex development should be considered 3
- However, the question stem specifies unilateral presentation, and hypospadias association is not specifically tied to laterality
Congenital Heart Defects
There is no established direct association between isolated undescended testis and congenital heart defects in the provided evidence. Congenital heart defects would be more relevant if the cryptorchidism were part of a broader syndromic presentation, which is not indicated in this case presentation.
Clinical Implications for This Patient
For this pediatric case with unilateral undescended left testis and underdeveloped left scrotum:
- Examine carefully for inguinal hernia on the affected side 1
- The underdeveloped scrotum (scrotal hypoplasia) is consistent with the undescended testis and may increase risk of testicular reascent after surgical repair 4
- Refer to a surgical specialist by 6 months of age (corrected for gestational age) if spontaneous descent has not occurred 3
- Do not obtain imaging studies prior to referral, as they rarely assist in decision-making 3