Physical Changes in Testicular Atrophy
Position of Atrophied Testes
Atrophied testicles typically sit higher in the scrotum rather than dangling lower. 1 When testicular volume decreases below 12 mL—the threshold defining atrophy—the reduced mass and altered tissue architecture cause the testis to retract upward within the scrotal sac. 1 This occurs because the cremasteric muscle and supporting structures maintain their baseline tone while the testicular mass itself diminishes, effectively pulling the smaller testis into a more superior position. 1
The higher position is particularly noticeable when comparing an atrophied testis to a normal contralateral testis, where size discrepancy greater than 2 mL or 20% becomes clinically apparent. 1 This asymmetry in both volume and position should prompt ultrasound evaluation to exclude underlying pathology. 1
Scrotal Skin Changes
Yes, the scrotal skin does become excess and baggy when testicles atrophy. 2 The scrotum's surface area was originally proportioned to accommodate normal-sized testes (typically 15–18 mL), so when testicular volume shrinks below 12 mL, the scrotal skin envelope remains relatively unchanged, creating visible redundancy and laxity. 1, 2
Specific Scrotal Findings in Atrophy:
Reactive hydrocele (fluid accumulation) can develop alongside testicular atrophy, further altering scrotal appearance and contributing to a baggy, pendulous appearance. 2
Scrotal wall thickening may occur with certain inflammatory conditions like epididymo-orchitis, which can both cause testicular atrophy and modify scrotal skin texture. 2
Physical examination should specifically evaluate scrotal skin for thickening, which may indicate ongoing inflammatory processes contributing to the atrophy. 2
Clinical Context and Diagnostic Implications
When examining a patient with suspected testicular atrophy, the combination of higher testicular position and excess scrotal skin should prompt:
Testicular volume measurement using Prader orchidometer or ultrasound, as volumes below 12 mL are definitively considered atrophic and associated with impaired spermatogenesis and increased cancer risk. 1
Hormonal evaluation including morning FSH, LH, and total testosterone on two separate occasions, as elevated FSH above 7.6 IU/L indicates spermatogenic failure. 1, 3
Scrotal ultrasound when physical examination is difficult due to thickened scrotal skin, large hydrocele, or when testicular masses are suspected. 1, 2
Common Pitfalls to Avoid:
Do not assume that baggy scrotal skin alone indicates atrophy—confirm with objective volume measurement, as scrotal laxity can occur with aging or weight loss independent of testicular size. 1
Recognize that unilateral atrophy with compensatory contralateral hypertrophy may mask the overall scrotal appearance changes, making bilateral palpation and comparison essential. 1
In men under 30–40 years with testicular volume below 12 mL, there is a ≥34% risk of intratubular germ cell neoplasia if testicular cancer develops, mandating closer surveillance and consideration of biopsy. 1