How do I approach a scrotal swelling or an empty scrotum?
Scrotal questions in surgery follow a fixed logic: Is the testis in the scrotum? Is it painful? Can I get above the swelling? Does it transilluminate? The answers separate an undescended testis (empty or small scrotum), torsion (acute pain), hydrocele (painless, transilluminates), varicocele (left-sided, bag of worms) and epididymitis (inflammatory pain).
| Condition | Pain | Key sign | Imaging / next step |
|---|---|---|---|
| Undescended testis | Usually painless | Empty hemiscrotum; testis in canal or abdomen | Palpation; ultrasound has limited value for nonpalpable testis |
| Retractile testis | None | Normal scrotum with rugae; testis can be brought down | Observe yearly |
| Torsion | Acute, severe | High-riding tender testis; cremasteric reflex often absent | Doppler ultrasound if it does not delay surgery; surgical exploration |
| Hydrocele | Painless | Fluctuant; transilluminates | Clinical; ultrasound if testis cannot be felt |
| Varicocele | Dull ache or none | Left-sided; bag of worms | Doppler ultrasound; semen analysis if infertile |
| Epididymitis | Gradual | Tender epididymis; urethritis or urinary symptoms | Urine tests; antibiotics |
What is an undescended testis (cryptorchidism)?
Cryptorchidism is the most common congenital abnormality of the male genitalia: absence of at least one testis from the scrotum. It can be unilateral or bilateral and is slightly commoner on the right. StatPearls gives an incidence of about 3% in full-term and 30% in premature male infants. Spontaneous descent is unlikely if the testis has not descended by 6 months.
The testis can lie anywhere along the normal path of descent — abdominal, near the internal ring, or in the inguinal canal (most commonly) — or it may be ectopic (outside the normal path), hypoplastic, dysgenetic or absent (anorchia). The raised temperature of the abdomen or canal disturbs spermatogenesis. For anatomy of the route, revise the inguinal canal and development of the genitourinary system.
How do I tell a retractile testis from a true undescended testis?
A retractile testis is a normal testis that is pulled upward by an overactive cremaster reflex; it sits in the groin but can be manipulated into the scrotum and stays there for a while. StatPearls notes that a scrotum with normal rugae that contains a testis may suggest a retractile testis, which typically needs no treatment. Retractile testes are more prevalent than undescended testes and do not need surgical correction.
| Feature | Retractile testis | True undescended testis |
|---|---|---|
| Scrotum | Well developed, normal rugae | Underdeveloped, often empty hemiscrotum |
| Manipulation | Can be brought down and stays briefly | Cannot be brought into the scrotum, or springs back |
| Mechanism | Active cremasteric reflex | Failure of descent or abnormal pathway |
| Treatment | Observation; annual examination | Orchiopexy |
| Risk | Some can become an acquired undescended testis | Infertility, torsion, hernia, germ cell tumour |
When and how is an undescended testis treated, and what are the complications?
- Examine warm, relaxed, with a careful palpation of groin and scrotum; document position.
- If the testis has not descended by 6 months, plan surgery — orchiopexy between 6 and 18 months to bring the testis into the scrotum and reduce the risk of infertility.
- Palpable testis → orchiopexy to place it in the scrotum.
- Nonpalpable testis → laparoscopy is the usual diagnostic and therapeutic tool. Routine ultrasound is unhelpful (reported sensitivity 45% and specificity 78%); even with a negative ultrasound, about 49% of boys with a nonpalpable testis have an intra-abdominal testis.
- High intra-abdominal testis → Fowler-Stephens orchiopexy (gonadal vessels divided; one-stage or two-stage laparoscopic technique).
| Complication | Detail |
|---|---|
| Infertility | About 10% to 30% in unilateral disease; 35% to 65% or more in bilateral disease; may exceed 90% if bilateral cryptorchidism is left untreated |
| Germ cell tumour | Increased risk; overall risk is below 1% |
| Torsion | Listed complication of untreated cryptorchidism |
| Inguinal hernia | Listed complication of untreated cryptorchidism |
| Psychological impact | Psychological issues |
What is testicular torsion and why is it an emergency?
Testicular torsion is twisting of the spermatic cord that cuts off the testicular blood supply. Testicular viability falls sharply after about 6 hours from symptom onset, so early diagnosis is the whole game. It peaks in the adolescent age group, though it can occur at any age, including before birth. The predisposing defect is the bell-clapper deformity — a high attachment of the tunica vaginalis that lets the testis hang and rotate within the sac — and it is bilateral in at least two-fifths of cases. Neonates tend to develop extravaginal torsion; adolescents typically have intravaginal torsion.
- Presentation — acute testicular pain, a swollen, erythematous, tender testis; the cremasteric reflex is often absent, although StatPearls cautions that its presence or absence is less sensitive than once thought.
- Prehn sign (relief of pain on elevation) is not reliable for predicting torsion.
- Imaging — scrotal ultrasound with Doppler is the ideal modality, but if clinical suspicion is high, call urology immediately and do not delay surgery.
- Treatment — surgical exploration with detorsion and orchiopexy. Manual detorsion may be attempted if urology is not immediately available. Contralateral orchiopexy is always done to prevent future torsion.
What is a hydrocele and how is it different from a hernia?
A hydrocele is an abnormal collection of serous fluid between the two layers of the tunica vaginalis around the testis. During normal descent a peritoneal fold, the processus vaginalis, accompanies the testis into the scrotum and normally closes. A congenital hydrocele results from failure of this process to obliterate. The patient has a painless scrotal swelling that makes the testis hard to palpate, is fluctuant and transilluminates.
| Type | Basis | Pointer |
|---|---|---|
| Congenital / communicating | Patent processus vaginalis; fluid moves between abdomen and scrotum | Swelling varies with position; hernia risk if the channel is wide |
| Infantile | Processus vaginalis obliterated at the deep inguinal ring but patent below | Obliteration at the deep ring, patent below it |
| Primary adult (non-communicating) | No communication with the peritoneal cavity | Slowly enlarging painless swelling |
| Secondary | Infection (epididymo-orchitis, filariasis, tuberculosis, syphilis), trauma or surgery, malignancy | Always look for the cause, especially a tumour |
What is a varicocele and why is it usually left-sided?
A varicocele is abnormal dilation of the pampiniform plexus that drains the testis. About 15% to 20% of all men have one, versus about 40% of infertile men. 80% to 90% are on the left: the right testicular vein drains directly into the low-pressure inferior vena cava, whereas the left joins the left renal vein, whose higher pressure impedes drainage. A large varicocele gives the 'bag of worms' feel and is evident on simple inspection; small varicoceles are detected only on a strong Valsalva manoeuvre. If a left varicocele is found, there is a 30% to 40% chance it is bilateral.
- Why left? Longer left testicular vein draining at a right angle into the left renal vein (higher pressure).
- Infertility link — treatment should be offered to infertile men with a palpable, clinically significant varicocele and abnormal semen parameters.
- Repair — open surgical ligation, percutaneous embolisation by interventional radiology, or antegrade scrotal sclerotherapy have roughly equivalent success and complication rates; embolisation is commonly used for recurrence.
How do I separate epididymitis from torsion in an acute scrotum?
Epididymitis is inflammation of the epididymis. In men under 39 years, Chlamydia trachomatis and Neisseria gonorrhoeae are the usual organisms; after 39 years, Escherichia coli and other coliforms predominate. For suspected sexually transmitted cases, ceftriaxone with doxycycline is recommended (azithromycin is an alternative) — see syndromic management of STIs.
| Feature | Torsion of testis | Torsion of appendix testis | Epididymitis |
|---|---|---|---|
| Age | Adolescents (peak), any age | 7 to 12 years | Under 39: STI organisms; over 39: E. coli |
| Onset | Sudden | Sudden | Gradual |
| Key sign | High-riding, tender testis; absent cremasteric reflex | Blue-dot sign | Tender epididymis, urethritis or urinary symptoms |
| Treatment | Emergency exploration | Usually conservative | Antibiotics |
What are the quick-recall points?
- Cryptorchidism: 3% term, 30% premature; commonest site inguinal canal.
- Orchiopexy at 6 to 18 months; laparoscopy for nonpalpable; Fowler-Stephens for high intra-abdominal testis.
- Retractile testis: normal rugae, no surgery, yearly review.
- Complications: infertility (worse if bilateral), germ cell tumour, torsion, hernia.
- Torsion: 6 hours, bell-clapper, absent cremasteric reflex, surgery plus contralateral orchiopexy.
- Hydrocele: transilluminates; hernia has cough impulse and does not transilluminate.
- Varicocele: left 80% to 90%, left renal vein drainage, bag of worms.
- Epididymitis: Chlamydia and gonorrhoea under 39, E. coli over 39.