Testicular Biopsy Technique and Fertility Implications in Contralateral Testis

Recommended Biopsy Technique

The European Association of Urology recommends an open incisional biopsy approach rather than 14-gauge Tru-Cut needle or fine-needle aspiration for contralateral testicular biopsy in the setting of undescended testis, as it allows for proper tissue handling with Stieve's or Bouin's fixation for accurate detection of testicular intraepithelial neoplasia (TIN) 1
The American Urological Association suggests that the inguinal approach with early spermatic cord control at the internal inguinal ring is mandatory before any testicular manipulation to prevent tumor spread and ensure proper surgical technique 2, 3
Open biopsy allows adequate tissue sampling for histological assessment of TIN, which has very high sensitivity and specificity when performed correctly, according to the European Association of Urology 2, 4

The American Society for Reproductive Medicine states that patients with unilateral undescended testis have a 3-5% risk of TIN in the contralateral descended testis, with the highest risk (≥34%) when testicular volume is <12 ml and age <40 years 2, 4, 3
The European Society of Human Reproduction and Embryology notes that the contralateral descended testis in unilateral cryptorchidism may have structural abnormalities, including smaller volume, softer consistency, and lower spermatogonia/tubule ratios, indicating baseline impairment independent of biopsy 5
If untreated, TIN progresses to invasive testicular cancer in 70% of cases within 7 years, as reported by the American Cancer Society 2, 4

The National Comprehensive Cancer Network recommends that high-risk patients, defined as those with testicular atrophy (volume <12 ml) and age <40 years, undergo contralateral biopsy, as they have a ≥34% TIN risk 2, 1, 4
The European Association of Urology suggests performing contralateral biopsy at the time of orchiectomy for the undescended testis to avoid a second procedure 1
The American Society of Clinical Oncology recommends waiting a minimum of 2 years after chemotherapy before biopsy, as chemotherapy eradicates TIN in two-thirds of patients 2, 4, 3

The American Urological Association advises informing patients that biopsy detection of TIN allows definitive treatment (radiotherapy 20 Gy) but destroys fertility 2, 4, 3
The European Association of Urology notes that surveillance is an acceptable alternative with regular ultrasound monitoring, accepting the risk of delayed cancer detection 2, 3
The American Society for Reproductive Medicine states that fertility potential is often already compromised in this population independent of biopsy 4, 3
The European Society of Human Reproduction and Embryology reports that paternity rates with unilateral cryptorchidism approach normal, so preserving the contralateral testis function is paramount 5

In postpubertal children with undescended testes, consideration should be given to performing either orchiectomy or biopsy, particularly when the contralateral testis is normal, due to a significantly elevated cancer risk and limited fertility benefit of orchidopexy after puberty, as recommended by the American Urological Association 6, 7, 8
The status of the contralateral testis is a key decision point, with orchiectomy generally preferred over biopsy for postpubertal undescended testes if the contralateral testis is normal, according to the European Association of Urology 6, 9

Testicular biopsy for fertility preservation is an emerging experimental indication in prepubertal boys facing gonadotoxic chemotherapy or hematopoietic stem cell transplantation, as suggested by the American Society of Clinical Oncology, although methods to use this tissue remain experimental 10

Routine testicular biopsy is NOT indicated in prepubertal boys with cryptorchidism, with the standard of care being orchidopexy by 18 months of age, as recommended by the American Academy of Pediatrics 6, 7, 8, 11, 12

Contralateral testicular biopsy to detect testicular intraepithelial neoplasia (TIN) may be offered in high-risk adult patients, particularly those with testicular atrophy and age <40 years, or extragonadal germ cell tumors, as recommended by the European Society for Medical Oncology 13, 14, 15, 16

Tissue must be preserved in Stieve's or Bouin's solution (NOT formalin) for proper TIN detection, as recommended by the College of American Pathologists 16