Scrotal Lump

Most scrotal lumps are painless and noticed incidentally by the patient or a partner. Most men will experience one of the causes below at some point in their lives.

Causes: epididymal cyst, testicular cancer, hydrocele, varicocele, inguinoscrotal hernia.

Testicular cancer

The most common solid cancer in men aged 18–39, though rare overall (~750 Australian men diagnosed annually). Most scrotal swellings are benign (cysts, hydrocele), but an enlarged testicle can be an early sign of a tumour — embarrassment often delays young men from seeking review. There’s currently no evidence that regular testicular self-examination reduces mortality, but men should be aware of their baseline and encouraged to present early if a change is noticed.

Risk factors: family history, history of undescended testis, history of congenital inguinal hernia.

Examination: a hard, firm, craggy structure within the testicular body, often disrupting the smooth testicular surface.

Investigation and management: ultrasound first; refer to urology if a suspicious solid structure is found.

Epididymal cyst (spermatocele)

A harmless cystic structure in the epididymis, more common from around age 40 and rare in children until adolescence. Usually painless unless large enough to cause mass effect. Transillumination usually allows light through. Should still be investigated (ultrasound is usually sufficient) if any testicular cancer risk factors are present. Complex cysts should be monitored; most cysts in children come and go without treatment. Urological referral is an option for pain related to size, or for cosmetic reasons.

Hydrocele

A fluid-filled sac around the testis, feeling like a balloon — most develop without an apparent cause and are more common in children and men over 40; can be unilateral or bilateral. Not painful, and size varies widely. Examination/investigation mirrors an epididymal cyst. Most hydroceles in children resolve spontaneously; if still present after 15–18 months, they can be surgically managed. Large, symptomatic hydroceles that don’t respond to supportive underwear can be surgically removed or drained (drained hydroceles tend to recollect) or treated with sclerotherapy.

Varicocele

A varicosity of the pampiniform venous plexus of the spermatic cord, present in ~15% of males of all ages — usually left-sided (due to left-right differences in gonadal/renal venous anatomy), though can occur bilaterally. Often develops in childhood but becomes more prominent from adolescence as blood flow increases; there’s a genetic predisposition. Worsens with standing (gravity-dependent) and improves lying down; may re-fill with a Valsalva manoeuvre when lying. Usually painless but can ache after exercise or in hot weather. Examination classically feels like a “bag of worms.” Transillumination shows reduced (but not absent) light transmission from the vessels.

Venous dilatation impairs normal countercurrent testicular thermoregulation, which can cause testicular atrophy and subfertility from oligospermia — usually harmless otherwise. Ultrasound helps differentiate from other causes and assess for testicular cancer risk factors; rarely, a retroperitoneal malignancy presents with a varicocele, so clinical assessment for a renal mass, hypertension, and haematuria matters more than reflexive imaging.

When to refer: symptoms, or a > 10% discrepancy in testicular volume, should prompt a non-urgent referral. Whether asymptomatic varicoceles without volume discrepancy should also be treated to protect future fertility remains controversial. Elective surgical correction (ligation of the testicular vessels — the Palomo procedure) is very effective and now usually performed laparoscopically; interventional radiology (embolisation) is also effective and may be standard in some centres.

Inguinal hernia

A very common paediatric surgical condition (3–5% of full-term infants, 13% of infants born before 33 weeks). Like an infantile hydrocele, the underlying pathology is a patent processus vaginalis (PPV) — wide in a hernia (allowing bowel/omentum, or ovaries in girls, to herniate) versus narrow in a hydrocele (transmitting only fluid).

Distinguishing an inguinal hernia from a hydrocele on examination:

• Cannot get above the swelling at the scrotal neck (can with a hydrocele).
• Usually reducible, unless incarcerated (a hydrocele is not reducible).
• Does not transilluminate reliably (a hydrocele transilluminates well, though this is unreliable in neonates).

No investigation is required for a suspected or confirmed inguinal hernia. Urgency of referral varies with age. All cases require inguinal herniotomy (ligation of the PPV) — a “watch and see” approach is not advised in Australia given the morbidity of incarceration and the low likelihood of spontaneous PPV closure once herniated.

Infantile hydrocele

Fluid around the testis from transmission of peritoneal fluid via a PPV — the straw- coloured fluid gives a “bluish hue” through the skin that’s often mistaken for something sinister. Irreducible, transilluminates brilliantly. No investigation is needed. Referral should be deferred until after age 3, since 90% resolve spontaneously by then as the narrow PPV closes; ligation of the PPV thereafter is an elective day procedure (for cosmesis).

Differential summary

Feature	Inguinal hernia	Hydrocele	Encysted hydrocele of the cord	Undescended testis
Reducible?	Yes, unless incarcerated	No	No	No
Skin changes	Possible if incarcerated	No	No	No
Tender	Yes, if incarcerated	No	No	No
Can get above it?	No	Yes	Yes (moves with cord traction)	Yes
Transilluminates	No (except thin-walled neonatal bowel)	Yes	Often, not always	No
Management	Refer to paediatric surgeon	Observe — usually resolves by age 2; refer if persisting	As for hydrocele	Refer to paediatric surgeon