Clinical Evaluation of Small Testicles with Normal Hormone Levels

Introduction to Testicular Size and Function

The American Urological Association suggests that testicular volume <12 mL is considered small or atrophic and associated with impaired spermatogenesis 1
The European Association of Urology indicates that FSH levels >7.6 IU/L indicate testicular dysfunction, even if they fall within the laboratory's reference range, and men with FSH >7.5 IU/L have a 5-13 fold higher risk of abnormal sperm concentration 2, 3

The American College of Physicians recommends obtaining semen analysis, as testicular size directly predicts sperm production, and performing at least two analyses separated by 2-3 months 5, 6, 3
The Endocrine Society suggests measuring complete hormonal panel including FSH, LH, total testosterone, SHBG, and prolactin, with FSH being the most important as it correlates strongest with testicular size and function 2, 3
The European Urology Association recommends performing scrotal ultrasound when physical examination is difficult, precise volume measurement is needed, or non-homogeneous testicular architecture is suspected 5, 7, 8

The American Society for Reproductive Medicine states that varicocele can cause small testicles with normal hormones, and correction can improve both testicular size and fertility 3
The European Association of Urology indicates that history of cryptorchidism can result in small testicles with normal hormones, even after successful orchidopexy, with reduced size and function 7

The American Urological Association suggests measuring testicular dimensions precisely using Prader orchidometer or ultrasound, obtaining complete hormonal evaluation, and performing semen analysis 8, 1, 2, 3
The European Association of Urology recommends karyotype analysis, Y-chromosome microdeletion testing, and scrotal ultrasound if testicular volume <12 mL or sperm concentration abnormal 6, 2, 3, 8

The American Cancer Society indicates that testicular volume <12 mL with history of cryptorchidism carries >34% risk of intratubular germ cell neoplasia in the contralateral testis, particularly in men under 30 years, and considers testicular biopsy in this specific population 1