Cryptorchidism (Undescended Testis)

Note on spelling: You wrote "cryptochordism" - this likely refers to cryptorchidism (from Greek kryptos = hidden, orchis = testis), also called undescended testis. That's what this answer covers.

Definition

Epidemiology

• Unilateral in ~75% of cases; bilateral in ~25%
• Most commonly the testis arrests in the inguinal canal (most frequent site)
• Intra-abdominal arrest accounts for only ~5-10% of cases

Embryology & Pathophysiology

1. Transabdominal phase - The testes descend from the posterior abdominal wall to the brim of the pelvis. This is controlled by Mullerian-inhibiting substance (MIS/AMH).
2. Inguinoscrotal phase - The testes pass through the inguinal canal into the scrotum. This phase is androgen-dependent, mediated by androgen-induced release of calcitonin gene-related peptide (CGRP) from the genitofemoral nerve.

• INSL3 (insulin-like 3 gene)
• LGRF8 (relaxin/insulin-like family peptide receptor 2)
• HOX gene family receptors (HOX10)

Possible Positions of an Undescended or Ectopic Testis

• Interstitial/superficial inguinal region (most common ectopic site)
• Perineum
• Femoral canal
• Suprapubic region
• Contralateral scrotum

Pathology (Histologic Changes)

• Thickening of the basement membrane of seminiferous tubules
• Loss of spermatogonia
• Sertoli cell-only tubules
• Scarred tubules with hyaline connective tissue
• Increased interstitial stroma
• Relative prominence of Leydig cells (relatively spared)
• Germ cell neoplasia in situ (GCNIS) may be present - a likely precursor to germ cell tumors

Clinical Features

• Usually asymptomatic - discovered when the scrotal sac is found empty
• Associated with inguinal hernia in 10-20% of cases (due to patent processus vaginalis)
• Risk of crush injury to a testis in the inguinal canal
• Associated conditions: hypospadias, Prader-Willi syndrome, Noonan syndrome

Complications

1. Infertility

• Bilateral cryptorchidism is the more serious fertility risk
• Paternity success rate after orchiopexy: 96% (unilateral) vs 70% (bilateral)
• Inhibin B levels (Sertoli cell/spermatogenesis marker) are significantly lower in bilateral cases (~1/3 of controls) vs unilateral (~2/3 of controls)
• Sperm density is lower even after correction; Leydig cell (testosterone) function is less affected

2. Testicular Cancer

• 4 to 10-fold increased risk of testicular germ cell tumors
• Risk falls to 2-3 fold if orchiopexy is performed prepubertally
• The contralateral normally descended testis is also at elevated malignant risk
• This bilateral risk supports the theory that cryptorchidism reflects an intrinsic (in utero) gonadal dysgenesis - not just a positional thermal insult

Management

Palpable Undescended Testis (e.g., in inguinal canal)

• Standard dartos pouch orchiopexy at 6-12 months of age
• Most inguinal cryptorchid testes that haven't spontaneously descended by 6 months are unlikely to do so

Nonpalpable Undescended Testis

• Diagnostic laparoscopy for unilateral nonpalpable testis
  • Blind-ending vessels → monorchia (absent testis) → ± excise remnant
  • Vessels exiting internal ring → inguinal exploration → orchiopexy
  • Intra-abdominal testis → Fowler-Stephens orchiopexy or orchiectomy
• hCG stimulation test for bilateral nonpalpable (to distinguish anorchia from bilateral intra-abdominal testes)
• Two-stage Fowler-Stephens orchiopexy for intra-abdominal testis: ligation of testicular vessels first (stage 1) → allow 6 months for collateral development → orchiopexy (stage 2)
• Laparoscopic orchiopexy has become a popular single-stage option for intra-abdominal testes

Medical (Hormonal) Treatment

• hCG or GnRH injections can be tried before surgery for inguinal/low testes
• Limited efficacy (~15-20% success) and mostly of historical interest now
• Current practice favors early surgical correction

Key Points Summary