What is a hydrocoele and does it need treatment?

A hydrocoele is a collection of fluid between the tissue layers surrounding the testis. It transilluminates — shines brightly when a light is held against it in a dark room — which distinguishes it from a solid mass. Most primary adult hydrocoeles are benign and need only observation. If the hydrocoele becomes large, heavy, or uncomfortable, surgical correction (Jaboulay or Lord's procedure) is straightforward with a recurrence rate under five percent. Aspiration alone is not recommended because recurrence is high and infection risk is not trivial. A hydrocoele that develops suddenly, follows trauma, or is secondary to infection needs ultrasound first to exclude an underlying cause.

What is a varicocoele and does it affect fertility?

A varicocoele is abnormal dilation of the pampiniform venous plexus — the 'bag of worms' palpable above and behind the testis, 90% on the left side. It affects 15–20% of men generally and about 40% of men with primary infertility. Venous stasis raises scrotal temperature and generates oxidative stress that can impair sperm production. For a man with a clinical Grade II–III varicocoele plus an abnormal semen analysis and ongoing fertility concerns, varicocoelectomy or percutaneous embolisation can improve semen parameters, though the live-birth benefit is modest per Cochrane review evidence. Asymptomatic varicocoeles with normal fertility do not need treatment.

Is an epididymal cyst the same as testicular cancer?

No. An epididymal cyst is a small fluid-filled cyst arising from the epididymis — the coiled tube behind the testis. It transilluminates, sits separately from the testis itself, and is completely benign, found incidentally on ultrasound in up to 40% of men. A spermatocoele is similar but contains milky fluid; clinically both are managed identically — observation. Neither requires treatment unless symptomatic. Testicular cancer, by contrast, is a solid mass within the testis itself that does not transilluminate. The two are clinically distinct on careful examination, but any diagnostic doubt warrants scrotal ultrasound.

How is testicular cancer detected early?

Testicular cancer most commonly presents as a painless firm lump within the testis — the testicle itself, not the soft cord behind it. Peak incidence is between 15 and 35 years. Men should report any new firm lump within the testis promptly, as testicular cancer is the most curable solid cancer — approximately 95% five-year survival when detected early. Scrotal ultrasound is the first investigation; if a solid intratesticular mass is confirmed, tumour markers (AFP, βhCG, LDH) are added before urgent urology referral. Sperm banking should be offered before orchidectomy.

Why is a right-sided varicocoele a red flag?

Varicocoeles are 90% left-sided because the left gonadal vein drains at a right angle into the left renal vein, making venous reflux more likely. The right gonadal vein drains directly into the IVC at an oblique angle, so isolated right-sided varicocoele is unusual. A new right-sided varicocoele raises concern for IVC obstruction — classically from renal cell carcinoma tumour thrombus. Any new or sudden-onset right-sided varicocoele, or one that does not decompress when the patient lies down, requires abdominal imaging urgently before referral to urology.

What is testicular self-examination?

Testicular self-examination is a monthly check performed after a warm shower, when the scrotal tissue is relaxed. The technique: support the testis gently with one hand and use the thumb and fingers of the other to feel the entire surface for any new firm lump within the testicle itself. The epididymis behind the testis is soft and rope-like — this is normal. The key warning sign is a new, firm, painless lump within the testis, which can be the size of a pea. Report anything new promptly to your GP for examination and ultrasound if needed.

Scrotal swelling

Scrotal swelling — hydrocoele, varicocoele and epididymal cyst in AU practice

By Dr HB Lo, FACRRM Reviewed 28 August 2026 8 min read

Scrotal swelling in adult men is overwhelmingly benign — hydrocoele (fluid around the testis), varicocoele (dilated scrotal veins), epididymal cyst, or inguinoscrotal hernia account for most presentations.

Three diagnoses must be excluded first: a solid intratesticular mass (testicular cancer — ~95% curable when caught early), acute scrotal pain suggesting torsion, and a new right-sided varicocoele (red flag for IVC obstruction from renal cell carcinoma).

Scrotal ultrasound is first-line for any uncertain mass. Most benign causes need only reassurance and observation; a solid intratesticular lesion warrants urgent urology referral within 24–72 hours.

Scrotal swelling in adult men

Scrotal swelling is a common and often anxiety-provoking presentation in general practice. The vast majority of causes are benign — a hydrocoele, varicocoele, epididymal cyst, spermatocoele, or inguinoscrotal hernia accounts for most cases. The GP’s first task is to exclude three diagnoses before reassuring the patient: a solid intratesticular mass (testicular cancer), acute scrotal pain suggesting testicular torsion, and a new or isolated right-sided varicocoele, which is a red flag for retroperitoneal pathology.

Testicular cancer carries approximately 95% five-year survival when caught early, making this a context where prompt clinical assessment and appropriate investigation genuinely changes outcomes. The lump that matters is solid, within the testis itself, does not transilluminate, and is typically painless — which is precisely why men often delay presenting, assuming pain is the key warning sign. It is not.

A. Core clinical — the AU general practice framework

History

A focused history guides both examination and investigation. Key questions include:

Onset and side — sudden onset, right-sided presentation, or a previously decompressing varicocoele that is no longer decompressing warrants urgent imaging
Pain — a varicocoele gives a dull dragging ache worse by day’s end; most hydrocoeles and cysts are painless; testicular tumour is usually painless (pain does not exclude cancer)
Change with position — varicocoele improves when supine; hydrocoele does not change; hernia may reduce
Fertility concerns — duration of trying to conceive, partner age, prior semen analysis results
Systemic symptoms — weight loss, back or flank pain, gynaecomastia (βhCG-secreting tumour), haematuria
Prior groin or scrotal surgery — vasectomy, orchidopexy, prior hernia or varicocoele repair
History of cryptorchidism — undescended testis is a significant testicular cancer risk factor

Examination — standing then supine

The scrotal examination should be performed in both the standing and supine positions. A varicocoele decompresses lying down; a hydrocoele does not change with position. The RACGP AFP 2018 guidance on scrotal lumps recommends a structured approach:

Inspect standing — asymmetry, scrotal skin changes, visible “bag of worms” (Grade III varicocoele visible through scrotal skin)
Palpate — size, side, consistency, separability from the testis, surface character (smooth vs nodular)
Transilluminate — fluid structures (hydrocoele, epididymal cyst, spermatocoele) transmit light and glow; solid structures (tumour, haematocoele, bowel in hernia) do not
Cough impulse and ability to get above the swelling — positive cough impulse plus inability to get above the swelling = inguinoscrotal hernia
Valsalva manoeuvre standing — augments varicocoele; converts Grade I to palpable
Cremasteric reflex — preserved in benign scrotal masses (absent in torsion, which is a surgical emergency)
Abdominal and lymph node examination — inguinal and supraclavicular (Virchow’s) nodes, abdomen; bilateral gynaecomastia screen

The key discriminating features: a hydrocoele surrounds the testis and transilluminates; a varicocoele sits above and behind the testis as a bag of worms, decompresses supine, and is augmented by Valsalva; an epididymal cyst is a small, well-separated, fluid cyst at the epididymal head that transilluminates; a hernia has a positive cough impulse and extends up into the inguinal canal; and a testicular tumour is solid, within the testis, and does not transilluminate.

Investigations

Scrotal ultrasound is the first-line investigation for any uncertain scrotal mass, any painful swelling, post-trauma assessment, or where examination is limited by size or discomfort. Therapeutic Guidelines (eTG) and USANZ both support ultrasound as the primary imaging modality, with high sensitivity for distinguishing intratesticular from extratesticular pathology, characterising varicocoele with Doppler, and identifying features of malignancy.

Tumour markers (AFP, βhCG, LDH) — ordered for any solid intratesticular mass confirmed on ultrasound, before referral. These also serve as pre-treatment baseline for post-orchidectomy staging and surveillance.

Abdominal ultrasound or contrast CT — mandatory for any new right-sided or sudden-onset varicocoele to exclude renal cell carcinoma, retroperitoneal mass, or IVC obstruction. This imaging should be arranged at the time of referral, not deferred to the specialist.

Semen analysis — for any man with a clinical varicocoele and fertility concerns. WHO 2021 sixth edition reference values apply; two analyses at least three weeks apart are required. Add FSH, LH, total testosterone, and prolactin if the semen analysis is significantly abnormal.

B. Evidence appraisal — varicocoele and fertility

The relationship between varicocoele and male infertility is one of the more contested areas in urology. The key conclusions from the evidence base:

Semen parameters improve after repair of clinical varicocoele. Across multiple studies and Cochrane reviews, varicocoelectomy and percutaneous embolisation consistently improve sperm concentration, motility, and morphology in men with palpable (Grade II–III) varicocoeles and abnormal semen analysis. This finding is robust.

Live-birth benefit is modest and variable. Cochrane review by Persad 2021 and the earlier Kroese 2012 review show a pregnancy-rate signal from varicocoele repair, but the confidence intervals are wide, the number of high-quality trials is limited, and the absolute benefit in live-birth rates in unselected couples is difficult to define.

Subclinical (ultrasound-only) varicocoeles should not be repaired. EAU guidelines 2024 are explicit: treatment of subclinical varicocoele — detectable only on ultrasound, not clinically palpable — shows no fertility benefit. This is a critical point: do not refer for repair based on ultrasound findings alone without clinical palpation confirming Grade II–III.

Microsurgical varicocoelectomy vs percutaneous embolisation. Microsurgical sub-inguinal varicocoelectomy has a lower recurrence rate (~1–3% vs ~10% for embolisation) but requires general or regional anaesthesia. Embolisation avoids surgical incision and has faster recovery but is operator-dependent and not universally available. Both are appropriate for a clinical varicocoele meeting criteria for intervention.

Antioxidant adjuncts. Cochrane review (Smits 2019) shows a modest pooled signal from antioxidants (vitamin C, vitamin E, CoQ10, zinc, l-carnitine) in male-factor infertility, but the evidence is heterogeneous and formulations vary. Antioxidants are a reasonable low-harm adjunct but do not replace varicocoele repair or ART.

C. The right-sided varicocoele red flag

The anatomy of gonadal venous drainage explains the left-sided predominance of varicocoele: the left gonadal vein drains at a right angle into the left renal vein, predisposing it to venous reflux and pressure transmission. The right gonadal vein drains at an oblique angle directly into the IVC, making isolated right-sided varicocoele anatomically uncommon.

When a right-sided varicocoele presents de novo — especially in a man over 40 — or when a previously decompressing varicocoele on either side stops decompressing supine, the clinical concern is obstruction of the IVC or right gonadal vein. The classic cause is renal cell carcinoma with tumour thrombus extending into the IVC, but retroperitoneal lymphoma, sarcoma, or nodal disease can produce the same picture. EAU guidelines are unambiguous: right-sided or sudden-onset varicocoele mandates abdominal imaging before referral.

In practice, arrange the abdominal ultrasound or CT simultaneously with the urology referral. If the patient has constitutional symptoms (weight loss, flank pain, haematuria), prioritise urgent CT and consider same-day hospital review.

D. Australian operations

MBS item numbers. Scrotal ultrasound (MBS 55600–55603) is the first-line investigation. Abdominal ultrasound for a right-sided varicocoele workup (56507) or contrast CT abdomen (56807) for urgent assessment. Tumour markers AFP, βhCG, LDH (66695 range). Semen analysis (73450). Standard GP consultations 23 / 36 / 44; urology specialist referral consultations 104–106. Hydrocoelectomy (37623 range) and varicocoelectomy (37606 range) are specialist-billed surgical items.

PBS. NSAIDs are general schedule for painful varicocoele symptom management. Testosterone replacement therapy, if required downstream from testicular failure after orchidectomy, is PBS Authority Required (two early-morning testosterone measurements below threshold; specialist-initiated). ART medications for fertility are PBS-listed with specialist initiation.

Mental Health Care Plan. New testicular cancer diagnosis, infertility-related distress, and post-surgical body image concerns are appropriate triggers for a Mental Health Care Plan (MBS 2715/2717) and Better Access psychology referral.

Telehealth. Results consultations, fertility counselling, and follow-up are appropriate by telehealth under the 12-month existing-relationship rule. The initial scrotal examination requires in-person assessment.

Medico-legal documentation. The dominant risk is failure to image a solid scrotal swelling. Document the transillumination result, separability from testis, cough impulse finding, and the scrotal ultrasound request in the clinical record. For a right-sided or sudden varicocoele, document the abdominal imaging request and the reasoning explicitly.

E. Special populations

Adolescents. Varicocoele is common at puberty. A Grade III varicocoele with greater than 20% ipsilateral testicular volume asymmetry warrants paediatric urology referral, as early intervention may preserve testicular growth and future spermatogenic capacity. Most adolescent varicocoeles without hypotrophy are observed.

Men seeking fertility. A varicocoele in the context of infertility warrants a structured approach: two semen analyses, hormonal assessment if abnormal (FSH, LH, testosterone), and shared decision-making about varicocoele repair vs ART vs combined approach. Offer a pre-conception couple consultation addressing lifestyle factors — scrotal cooling (boxer shorts, avoid hot baths and laptops on lap), smoking cessation, and weight optimisation where relevant.

Older men. A secondary hydrocoele in an older man warrants imaging to exclude infection, post-hernia repair lymphatic disruption, or underlying tumour before reassurance is offered.

Aboriginal and Torres Strait Islander men. Culturally safe engagement is essential. MBS 715 Health Assessment provides a systematic opportunity to examine men who may not otherwise present for scrotal symptoms. ATSI Health Practitioner follow-up items (10987) support re-screening and treatment completion.

When to escalate

Refer or escalate when:

Solid intratesticular mass on examination or ultrasound — urgent urology within 24–72 hours; same-day if metastatic features
New or sudden-onset right-sided varicocoele — arrange abdominal imaging urgently, then refer urology
Acute severe scrotal pain — refer immediately to emergency (rule out torsion — surgical window is 4–6 hours)
Infertility with clinical Grade II–III varicocoele and abnormal semen analysis — urology or fertility specialist
Adolescent Grade III varicocoele with greater than 20% ipsilateral testicular hypotrophy
Large, symptomatic hydrocoele or epididymal cyst affecting quality of life — elective urology
Constitutional symptoms (weight loss, haematuria, back pain) with any scrotal mass

What this article is and is not

This is general health information drawn from current Australian general practice guidelines — Therapeutic Guidelines, USANZ, RACGP, and Cancer Council Australia — and international urology and male reproductive standards. It is not personal medical advice and does not create a doctor–patient relationship. Decisions about investigation and management are made with your own GP and treating clinicians.

Testicular self-examination: perform monthly after a warm shower when scrotal tissue is relaxed. Feel the entire surface of each testis for any new firm lump within the testis itself — not the soft rope-like cord behind it, which is the epididymis. A new, firm, painless lump the size of a pea or larger within the testis is the warning sign. Report it promptly.

Consumer resources: HealthDirect — Scrotal lumps, Healthy Male, Cancer Council Australia, Better Health Channel.

Sources cited

Frequently asked questions

What is a hydrocoele and does it need treatment?

A hydrocoele is a collection of fluid between the tissue layers surrounding the testis. It transilluminates — shines brightly when a light is held against it in a dark room — which distinguishes it from a solid mass. Most primary adult hydrocoeles are benign and need only observation. If the hydrocoele becomes large, heavy, or uncomfortable, surgical correction (Jaboulay or Lord's procedure) is straightforward with a recurrence rate under five percent. Aspiration alone is not recommended because recurrence is high and infection risk is not trivial. A hydrocoele that develops suddenly, follows trauma, or is secondary to infection needs ultrasound first to exclude an underlying cause.
What is a varicocoele and does it affect fertility?

A varicocoele is abnormal dilation of the pampiniform venous plexus — the 'bag of worms' palpable above and behind the testis, 90% on the left side. It affects 15–20% of men generally and about 40% of men with primary infertility. Venous stasis raises scrotal temperature and generates oxidative stress that can impair sperm production. For a man with a clinical Grade II–III varicocoele plus an abnormal semen analysis and ongoing fertility concerns, varicocoelectomy or percutaneous embolisation can improve semen parameters, though the live-birth benefit is modest per Cochrane review evidence. Asymptomatic varicocoeles with normal fertility do not need treatment.
Is an epididymal cyst the same as testicular cancer?

No. An epididymal cyst is a small fluid-filled cyst arising from the epididymis — the coiled tube behind the testis. It transilluminates, sits separately from the testis itself, and is completely benign, found incidentally on ultrasound in up to 40% of men. A spermatocoele is similar but contains milky fluid; clinically both are managed identically — observation. Neither requires treatment unless symptomatic. Testicular cancer, by contrast, is a solid mass within the testis itself that does not transilluminate. The two are clinically distinct on careful examination, but any diagnostic doubt warrants scrotal ultrasound.
How is testicular cancer detected early?

Testicular cancer most commonly presents as a painless firm lump within the testis — the testicle itself, not the soft cord behind it. Peak incidence is between 15 and 35 years. Men should report any new firm lump within the testis promptly, as testicular cancer is the most curable solid cancer — approximately 95% five-year survival when detected early. Scrotal ultrasound is the first investigation; if a solid intratesticular mass is confirmed, tumour markers (AFP, βhCG, LDH) are added before urgent urology referral. Sperm banking should be offered before orchidectomy.
Why is a right-sided varicocoele a red flag?

Varicocoeles are 90% left-sided because the left gonadal vein drains at a right angle into the left renal vein, making venous reflux more likely. The right gonadal vein drains directly into the IVC at an oblique angle, so isolated right-sided varicocoele is unusual. A new right-sided varicocoele raises concern for IVC obstruction — classically from renal cell carcinoma tumour thrombus. Any new or sudden-onset right-sided varicocoele, or one that does not decompress when the patient lies down, requires abdominal imaging urgently before referral to urology.
What is testicular self-examination?

Testicular self-examination is a monthly check performed after a warm shower, when the scrotal tissue is relaxed. The technique: support the testis gently with one hand and use the thumb and fingers of the other to feel the entire surface for any new firm lump within the testicle itself. The epididymis behind the testis is soft and rope-like — this is normal. The key warning sign is a new, firm, painless lump within the testis, which can be the size of a pea. Report anything new promptly to your GP for examination and ultrasound if needed.

Source quality

Sources grouped by evidence tier. AU primary tier first; international where AU is silent or lagging; named-author reconstruction where guidelines have not yet caught up. How tiers work.