What is the diagnosis for a young to middle-aged male patient with a left testis of normal size, palpable at the neck of the scrotum, with limited mobility and retracting back to the neck of the scrotum when released, while the right testis is normal?

Retractile Testis

The diagnosis is retractile testis of the left side, characterized by a testis that can be palpated at the neck of the scrotum, cannot easily be moved to the bottom of the scrotum, and retracts back to the neck when released—this distinguishes it from a normally descended testis but differs from true cryptorchidism because it can still be manipulated into the scrotal position. 1

Key Diagnostic Features

The defining characteristic of retractile testis is that it can be manipulated into the scrotum and remains there without traction, though in this case the limited mobility and immediate retraction suggest a hyperactive cremasteric reflex pulling the testis upward. 1 The American Urological Association notes that this represents an exaggerated physiologic response rather than true maldescent. 1

The critical distinction from true undescended testis (cryptorchidism) is that:

• True undescended testes cannot be easily manipulated into the scrotum or do not remain there at all 1
• In cryptorchidism, the testis is arrested along the path of descent and requires surgical intervention 1
• The normal size of the left testis in this case supports retractile testis rather than cryptorchidism, which often presents with testicular atrophy 2

Immediate Management Approach

Do not order imaging studies—ultrasound rarely assists in decision-making and has poor sensitivity (45%) and specificity (78%) for this clinical scenario. 1 The American Urological Association explicitly recommends against routine imaging for retractile testes. 1

Institute annual monitoring at well-child visits to assess for secondary ascent (acquired cryptorchidism), as retractile testes carry a 2-45% risk of becoming truly undescended during childhood. 1, 3 This risk is mechanistically related to hyperactive cremasteric reflex, foreshortened patent processus vaginalis, or entrapping adhesions. 1

Critical Follow-Up Parameters

At each annual examination, assess whether:

• The testis can still be manipulated into the scrotum and remains there without traction 1
• The testis has ascended and can no longer be brought down (secondary ascent) 1
• Testicular volume remains normal compared to the contralateral side 2

If secondary ascent occurs and the testis cannot be manipulated into the scrotum and kept there without traction at 15 months of age or older, refer immediately to a pediatric urologist or pediatric surgeon for orchiopexy. 1 The American Academy of Pediatrics emphasizes this threshold because germ cell damage begins after 15-18 months, with progressive loss of fertility potential. 1

Surgical Intervention Criteria

Orchiopexy should ideally be performed by 18 months if true undescended testis develops, to preserve fertility potential and reduce cancer risk. 1 In cases of confirmed secondary ascent, a patent processus vaginalis is identified in 68% of cases requiring surgery. 3

Do not use hormonal therapy (hCG or GnRH)—evidence shows low response rates (6-38% success) and lack of long-term efficacy. 1

Long-Term Surveillance Considerations

Even if the testis remains retractile without ascending:

• Continue annual monitoring until resolution (typically through puberty) 1, 3
• Retractile testes that undergo secondary ascent and require orchiopexy will need lifelong surveillance for testicular cancer, with relative risk 2.75-8 times higher 1
• Prepubertal orchiopexy reduces cancer risk 2-6 fold compared to postpubertal surgery 1

Common Pitfalls to Avoid

Failing to distinguish retractile from truly undescended testes leads to unnecessary imaging and delayed appropriate management. 1 The key is the ability to manipulate the testis into the scrotum, even if it immediately retracts. 1

Missing bilateral nonpalpable testes as a potential disorder of sex development can result in life-threatening adrenal crisis—though not applicable in this unilateral case with normal contralateral testis. 1

Ordering ultrasound wastes resources and provides no actionable information in most retractile testis cases. 1 Reserve imaging only for cases where physical examination is inadequate or testicular architecture assessment is needed. 2