Cryptorchidism and Hypospadias

• Persistent cryptorchidism raises the risk of infertility and of testicular germ cell cancer — and importantly the cancer risk applies to both testes and is not eliminated by orchiopexy, though surgery permits examination and improves fertility outcomes.
• Orchiopexy is generally performed between roughly 6 and 18 months. A non-palpable testis requires surgical evaluation rather than imaging.

• Circumcision is deferred, since the foreskin may be needed for surgical repair.
• Severe or proximal hypospadias with an undescended testis should prompt evaluation for a disorder of sexual development.

Hormonal (endocrine) causes — failure of the androgen/INSL3 axis

• Insufficient INSL3 signaling: Leydig-cell INSL3 acting on the RXFP2 receptor drives gubernacular swelling and the transabdominal phase; deficient signaling leaves the testis intra-abdominal.
• Androgen deficiency or resistance: the inguinoscrotal phase is testosterone/DHT-dependent. Hypogonadotropic hypogonadism (Kallmann syndrome, Prader-Willi), androgen insensitivity, and 5-alpha-reductase deficiency all impair descent and simultaneously cause hypospadias.
• Primary gonadal dysgenesis: Klinefelter syndrome, mixed gonadal dysgenesis, and other disorders of sexual development.

Mechanical/anatomic causes

• Gubernacular or processus vaginalis abnormalities, abdominal wall laxity (prune belly syndrome), and gastroschisis/omphalocele, where raised or altered intra-abdominal mechanics obstruct descent.
• Ectopic descent (superficial inguinal pouch, femoral, perineal) — the testis leaves the canal but misses the scrotum.

Non-modifiable risk factors examiners plant in the stem

• Prematurity and low birth weight — the single strongest association, since the inguinoscrotal phase occurs in the last trimester; incidence in preterm boys is several times that of term boys.
• Small for gestational age / intrauterine growth restriction, twin gestation, and a positive family history in a father or brother.
• Syndromic associations, and for hypospadias, a first-degree relative — familial clustering is well described.

Modifiable/exposure risk factors

• Maternal smoking and alcohol, maternal obesity and diabetes (including gestational).
• Exogenous hormone and endocrine-disruptor exposure — progestins, phthalates, and pesticides are the classic stem details for hypospadias.
• Assisted reproductive technology pregnancies show a modestly increased rate of both anomalies.

• Placental insufficiency deserves separate mention: hCG drives fetal Leydig-cell testosterone in early gestation, so poor placentation links growth restriction, hypospadias, and cryptorchidism into one mechanism.

Normal descent occurs in two hormonally distinct phases

• Transabdominal phase (roughly 8–15 weeks): Leydig-cell INSL3 binds RXFP2 on the gubernaculum, causing it to swell and anchor the testis near the internal ring while the cranial suspensory ligament regresses under androgen influence.
• Inguinoscrotal phase (roughly 25–35 weeks): androgen-dependent migration through the inguinal canal, mediated in part by the genitofemoral nerve and calcitonin gene-related peptide guiding gubernacular outgrowth. Because this phase is late, prematurity interrupts it — explaining the high preterm incidence and the high rate of spontaneous descent in the first months of life as the postnatal testosterone surge (mini-puberty) completes the job.

Why the retained testis is damaged

• The scrotum sits several degrees below core temperature. An abdominal or inguinal testis is chronically hyperthermic, which disrupts the normal transformation of gonocytes into Ad (dark) spermatogonia during the first months of life — the reserve stem cell pool for later spermatogenesis.
• Loss of that pool produces progressive germ cell depletion, tubular hyalinization, and reduced Leydig cell mass, which is why fertility outcomes depend on how early orchiopexy is done. Sertoli cells and hormone production are relatively spared, so most boys are not androgen-deficient.
• Heat-driven DNA damage plus underlying testicular dysgenesis explains the malignancy risk. The testicular dysgenesis syndrome hypothesis unifies cryptorchidism, hypospadias, impaired semen quality, and germ cell tumor as downstream effects of one abnormal fetal gonadal program — which is why the contralateral, normally descended testis also carries excess cancer risk.

Hypospadias

• The urethral folds fuse proximal to distal under DHT between about 8 and 14 weeks. Interrupted fusion leaves the meatus ventral at the point where fusion stopped, so the more proximal the meatus, the earlier and more severe the androgen defect.
• The same failure prevents circumferential preputial fusion, producing the dorsal hooded foreskin, and leaves fibrous ventral tissue in place of normal corpus spongiosum, tethering the shaft into ventral curvature (chordee).

Cryptorchidism

• Empty, hypoplastic hemiscrotum — the rugated scrotal skin is underdeveloped on the affected side because it never accommodated a testis. Unilateral and right-sided is most common.
• Palpable inguinal testis in most cases, felt in the canal or superficial inguinal pouch and not able to be brought to a dependent scrotal position.
• Non-palpable testis in a minority — either intra-abdominal, atrophic (vanishing testis from prenatal torsion), or absent.
• Associated inguinal hernia or hydrocele from the patent processus vaginalis that accompanied failed descent.
• Retractile testis is the key distractor: a brisk cremasteric reflex (L1–L2, genitofemoral nerve) pulls a normally descended testis up, but it can be milked into the scrotum and stays there once the reflex fatigues. This is a normal variant needing only annual follow-up, since a minority later ascend.

Hypospadias

• Ventral urethral meatus — glanular/coronal (most cases, distal), midshaft, or penoscrotal/perineal (proximal, most severe).
• Dorsal hooded foreskin with deficient ventral prepuce, often the finding that prompts referral.
• Chordee — ventral penile curvature, best appreciated with erection or stretch.
• Ventrally deflected or spraying urinary stream; older boys may need to sit to void. Proximal disease can cause sexual dysfunction later.

The red-flag combination

• Bilateral non-palpable testes plus hypospadias in an apparently male newborn — treat as a possible disorder of sexual development until proven otherwise. The stem may hide a virilized 46,XX infant with congenital adrenal hyperplasia, at risk for vomiting, hyponatremia, hyperkalemia, and shock in the second week of life.

Initial step — the physical examination, done well

• Warm hands, warm room, frog-leg or cross-legged position; sweep from the anterior superior iliac spine along the canal toward the scrotum, with soap or lubricant if needed. Repeat supine and standing in older boys.
• The examination answers the only question that changes management: palpable versus non-palpable.
• Distinguish retractile testis by milking the gonad into the scrotum and releasing — if it remains without tension, it is retractile and needs surveillance only.

Imaging

• The AUA cryptorchidism guideline explicitly recommends against ultrasound or other imaging before referral. Ultrasound cannot reliably exclude an intra-abdominal testis, so a negative study neither avoids surgery nor changes the operation — it only delays care. This is a favorite exam trap.

Non-palpable testis

• Refer to a pediatric urologist. Examination under anesthesia followed by diagnostic laparoscopy is the gold standard, simultaneously locating an intra-abdominal testis, confirming a blind-ending vas and vessels (vanishing testis), and permitting orchiopexy in the same setting.

Bilateral non-palpable testes — endocrine and genetic workup before surgery

• Karyotype and 17-hydroxyprogesterone to exclude a virilized 46,XX infant with congenital adrenal hyperplasia; also electrolytes, since salt-wasting is life-threatening.
• Serum AMH (Müllerian inhibiting substance) and inhibin B as markers of Sertoli-cell tissue: detectable AMH implies testicular tissue somewhere, whereas undetectable AMH with markedly elevated LH and FSH supports anorchia.
• hCG stimulation testing with a testosterone rise confirms functioning Leydig tissue when the picture is equivocal.

Hypospadias

• A clinical diagnosis; document meatal position, chordee, and prepuce. No routine imaging or karyotype for isolated distal hypospadias with descended testes.
• Proximal hypospadias with cryptorchidism, or any ambiguity, triggers DSD evaluation (karyotype, testosterone/DHT ratio, adrenal steroids, pelvic ultrasound).

Immediate concerns first

• A newborn with bilateral non-palpable gonads is a potential adrenal crisis waiting to happen — obtain karyotype, 17-OHP, and electrolytes and involve endocrinology before any elective surgery. Salt-wasting CAH is managed with fluid resuscitation, glucocorticoid (hydrocortisone) and mineralocorticoid (fludrocortisone) replacement.

Cryptorchidism — observation window

• Watchful waiting until about 6 months corrected age, because spontaneous descent driven by the postnatal androgen surge occurs in most cases and essentially none after that point. The AUA cryptorchidism guideline recommends referral to a surgical specialist if the testis has not descended by 6 months corrected age.

Definitive management

• Orchiopexy — surgical mobilization of the cord and fixation in a subdartos pouch, with ligation of the patent processus vaginalis. The AUA recommends completion by 18 months of age to maximize germ cell preservation.
• Palpable testis: inguinal or scrotal (Bianchi) approach.
• Non-palpable testis: diagnostic laparoscopy with single-stage or staged Fowler-Stephens orchiopexy (division of the testicular vessels, relying on collateral deferential/cremasteric supply) for high intra-abdominal testes.
• Post-pubertal or adult unilateral undescended testis: orchiectomy is generally favored given negligible fertility contribution and cancer risk in a non-examinable gonad.

Explicitly not recommended

• Hormonal therapy (hCG or GnRH analogues) to induce descent — the AUA recommends against it because efficacy is low and results are not durable.
• Pre-referral ultrasound, which delays definitive care.

Hypospadias

• Circumcision is contraindicated/deferred — the prepuce is graft material for urethroplasty; this is the single most testable management point, endorsed by the AAP.
• Single-stage repair (chordee correction plus tubularized incised plate/*Snodgrass* urethroplasty) is standard for distal disease; staged repair with preputial or buccal mucosal grafts for proximal disease. The AAP supports repair in infancy, generally between 6 and 12 months, when anesthetic risk is acceptable and before genital awareness.
• Preoperative topical or parenteral testosterone is sometimes used to enlarge a small glans/phallus.
• Isolated glanular hypospadias with a normal stream may reasonably be left unrepaired.

Complications of cryptorchidism

• Infertility: heat-mediated loss of Ad spermatogonia. Unilateral disease usually permits paternity near normal rates; bilateral disease produces substantially impaired semen parameters and is the higher-yield association. Earlier orchiopexy improves, but does not normalize, outcomes.
• Testicular germ cell tumor: several-fold increased risk, driven by dysgenetic germ cells; seminoma predominates in the uncorrected intra-abdominal testis. Key points examiners test — the risk applies to both testes, and orchiopexy reduces but does not eliminate it while making the gonad examinable. A painless firm testicular mass in a young adult with a surgical scar is the classic vignette.
• Inguinal hernia: the patent processus vaginalis persists; incarceration is a surgical emergency signaled by a tender, irreducible groin mass with vomiting.
• Torsion: an abnormally mobile undescended testis torses more readily. Acute lower abdominal or groin pain with an empty ipsilateral hemiscrotum is a surgical emergency and is frequently misread as appendicitis or gastroenteritis.
• Trauma against the pubic bone, and psychosocial impact of an empty scrotum in adolescence.

Complications of orchiopexy

• Testicular atrophy from vascular compromise — highest after Fowler-Stephens procedures; presents as a shrunken, soft scrotal testis on follow-up.
• Testicular re-ascent/retraction, vas deferens or epididymal injury with later obstructive infertility, wound infection, and hematoma.

Complications of hypospadias and its repair

• Urethrocutaneous fistula — the most common postoperative complication; urine exits from a second ventral opening.
• Meatal stenosis and urethral stricture: narrowed, forceful or prolonged stream, straining, and eventually retention or upper-tract changes.
• Urethral diverticulum with post-void dribbling, glans dehiscence, and recurrent chordee.
• Unrepaired proximal hypospadias causes deflected stream, difficulty with intravaginal ejaculation, and infertility.
• Inadvertent neonatal circumcision removes the tissue needed for reconstruction and complicates repair — a preventable iatrogenic complication.

• Timing is the answer to most cryptorchidism questions: observe to about 6 months corrected age, refer if still undescended, and complete orchiopexy by 18 months per the AUA cryptorchidism guideline.
• Do not order an ultrasound for a non-palpable testis. The AUA recommends against imaging; the correct next step is referral for examination under anesthesia and diagnostic laparoscopy. Ultrasound is the most common distractor on this topic.
• Retractile versus undescended: if the testis can be milked into the scrotum and stays, it is retractile — a normal variant with an exuberant cremasteric reflex (genitofemoral nerve, L1–L2) needing only annual re-examination.
• Cancer risk is bilateral and persists after surgery. Orchiopexy improves fertility and allows self-examination but does not abolish germ cell tumor risk, and the normally descended contralateral testis is also at increased risk. Seminoma is the classic tumor.
• Bilateral non-palpable testes = disorder of sexual development until proven otherwise. Get a karyotype and 17-hydroxyprogesterone to catch a virilized 46,XX infant with congenital adrenal hyperplasia before a salt-wasting crisis.
• Never circumcise an infant with hypospadias — the dorsal hooded foreskin is graft tissue for urethroplasty. This is the highest-yield single management fact for hypospadias.
• Hormonal therapy (hCG/GnRH) is not recommended to induce testicular descent; surgery is definitive.
• Acute groin or lower abdominal pain in a boy with an empty hemiscrotum is torsion of an undescended testis until excluded — a surgical emergency easily mistaken for appendicitis.
• Mechanism buzzwords: INSL3/RXFP2 for the transabdominal phase, androgen/DHT for the inguinoscrotal phase and for urethral fold fusion; failure of the same androgen program links hypospadias, cryptorchidism, and impaired spermatogenesis as testicular dysgenesis syndrome.