Lucan · Conditions

Scrotal lumps

Australian guidance: USANZ varicocele/scrotal mass guidance + RACGP AJGP clinical review + HealthPathways WA

1. Definition and epidemiology

A scrotal lump is any palpable swelling within or adjacent to the scrotum, arising from the testis, epididymis, spermatic cord, or the coverings of the tunica vaginalis. The differential ranges from entirely benign, self-limiting findings to a testicular malignancy that is potentially curable only if recognised early, so every scrotal mass is worked up with a structured bedside assessment rather than reflexive reassurance. This topic covers the chronic or subacute painless (or mildly uncomfortable) scrotal mass; the acutely painful scrotum, principally testicular torsion, torsion of a testicular appendage, and acute epididymo-orchitis, follows a distinct surgical-emergency pathway and is covered separately. Hydrocele is the most common cause of painless scrotal swelling seen in general practice, epididymal cysts and spermatoceles are common incidental findings that become more prevalent with age, and a varicocele is found on examination in a substantial minority of the adult male population. Testicular cancer, while comparatively rare in absolute terms, is the most common solid organ malignancy diagnosed in Australian men aged 15 to 39 years, which is why the bedside algorithm for any scrotal mass is built around excluding a testicular origin before a benign label is assigned.

2. Pathophysiology

The scrotal contents are enveloped by a coelomic remnant that underlies almost every benign scrotal mass. During fetal development the testis forms retroperitoneally and descends through the inguinal canal into the scrotum, preceded by a finger-like outpouching of peritoneum called the processus vaginalis, which drags the layers of the anterior abdominal wall down with it to form the inguinal canal and the coverings of the spermatic cord (Robbins Ch 21 Male Genital Tract). By late gestation the testis has descended into the scrotum while still connected to the peritoneal cavity through this processus vaginalis. Normally the proximal portion of the processus vaginalis obliterates around the time of birth, leaving only its distal portion as a closed, fluid-lined peritoneal sac draped over the anterolateral testis and epididymis: this residual sac is the tunica vaginalis, and its visceral layer (applied to the testis) and parietal layer (applied to the scrotal wall) normally contain only a thin film of serous fluid that lets the testis glide freely within the scrotum.

Failure of the processus vaginalis to obliterate is the anatomical basis of the two commonest paediatric scrotal and groin presentations. If the whole tract stays patent, peritoneal fluid can track freely between the abdomen and scrotum, producing a communicating hydrocele that classically fluctuates in size with activity and time of day, and the same open tract is the conduit through which bowel or omentum can herniate to form a congenital indirect inguinal hernia. If the tract obliterates patchily, fluid trapped within an isolated remnant along the cord produces an encysted hydrocele of the cord, a lump distinct from and above the testis. In adults, a hydrocele confined to the tunica vaginalis around the testis with no connection to the peritoneum is a non-communicating (simple) hydrocele; when idiopathic, it is termed primary and reflects an imbalance between the normal secretion and reabsorption of vaginal fluid by the mesothelial lining. A secondary hydrocele instead develops as a reactive exudate driven by an underlying process in the testis or epididymis, most importantly a tumour, but also infection, trauma, or torsion; because the resulting fluid can envelop and obscure a firm testicular mass on palpation, a new secondary hydrocele in a young man is treated as a possible testicular tumour until ultrasound proves otherwise.

The pampiniform plexus, a network of veins draining the testis that condenses into the testicular vein within the spermatic cord, is the structure implicated in varicocele. The right testicular vein drains obliquely and directly into the inferior vena cava, whereas the left testicular vein drains at a near right angle into the left renal vein, a geometrically disadvantageous configuration that raises resistance to venous return; this may be compounded by relative incompetence of the valves within the testicular vein and, in some men, by compression of the left renal vein between the superior mesenteric artery and the aorta (the so-called nutcracker effect). This anatomical asymmetry is why roughly nine in ten varicoceles are left-sided, why bilateral varicocele is common, and why an isolated right-sided varicocele is rare and mechanistically unexpected under normal anatomy. When a right-sided varicocele does appear, or when a varicocele on either side fails to decompress on lying supine, the presumption shifts from primary venous incompetence to a fixed mechanical obstruction of venous return, most importantly a retroperitoneal mass or a renal cell carcinoma invading or compressing the renal vein or inferior vena cava. Varicocele impairs spermatogenesis through several converging mechanisms: pooled, sluggish blood raises intrascrotal and intratesticular temperature above the two-to-four-degree gradient below core body temperature that spermatogenesis normally requires, and venous stasis promotes local hypoxia, retrograde reflux of adrenal and renal metabolites (particularly relevant on the left, given the direct connection to the renal vein), and oxidative stress from reactive oxygen species, together producing the reduced sperm concentration, motility, and normal morphology seen on semen analysis in affected men.

Epididymal cysts and spermatoceles both arise from cystic dilation of the epididymal tubules or efferent ductules; an epididymal cyst contains clear serous fluid while a spermatocele contains cloudy, sperm-laden fluid, but the two are frequently indistinguishable on examination or ultrasound and are managed identically. Haematocele describes blood accumulating within the tunica vaginalis, almost always following blunt trauma or a surgical or needle procedure on the scrotum; unlike hydrocele fluid, blood is optically opaque and does not transilluminate. Idiopathic scrotal oedema is a localised, non-infective inflammatory reaction confined to the dartos and subcutaneous tissue of the scrotal wall itself, sparing the testis and epididymis entirely; its precise trigger is unclear, though a localised allergic or angio-oedema-like reaction has been proposed.

3. Clinical presentation and diagnostic criteria

Every scrotal mass is assessed with the same four bedside questions, asked with the patient standing and again supine. First, can you get above the lump? Sliding the examining fingers upward between the top of the swelling and the pubic tubercle should meet normal cord structures with a clear upper border if the mass is confined to the scrotum; inability to get above it means the swelling continues up into the inguinal canal (inguinoscrotal), the hallmark of an inguinoscrotal hernia or, occasionally, a large hydrocele of the cord. Second, is the lump separate from the testis, or does it arise from the testis itself? A lump palpated distinctly from a normal, separately identifiable testis (for example, posterior to it, as with an epididymal cyst) is far less concerning than a mass that is inseparable from, or appears to replace, testicular tissue, which is treated as a testicular tumour until ultrasound proves otherwise. Third, does it transilluminate? In a darkened room, a torch held against the posterior scrotal skin will shine through a fluid-filled, cystic mass such as a hydrocele, epididymal cyst, or spermatocele with a uniform red-orange glow; a solid mass (tumour), a blood-filled mass (haematocele), and the tortuous veins of a varicocele do not transilluminate, and most hernias do not either. Fourth, is there a cough impulse? An expansile impulse on coughing, felt at the deep or superficial inguinal ring or over the swelling itself, is characteristic of an inguinal hernia because raised intra-abdominal pressure is transmitted through the patent peritoneal connection; a true scrotal lump with no connection to the peritoneal cavity does not cough impulse.

A simple hydrocele is a soft, non-tender, fluctuant swelling that fully surrounds the testis; the examiner can get above it, it transilluminates brightly, and it has no cough impulse. Communicating hydroceles in infants characteristically vary in size through the day. A varicocele feels like a soft, compressible "bag of worms" superior and posterior to the testis, most prominent when the patient is standing and performing a Valsalva manoeuvre, and it characteristically collapses or markedly reduces when the patient lies supine and the scrotum is gently elevated; it does not transilluminate. An epididymal cyst or spermatocele is a smooth, well-defined, cystic nodule felt separately from, and usually above or behind, the testis, and it transilluminates. An inguinoscrotal hernia cannot be got above, may show a cough impulse, and may be reducible (with or without a palpable gurgle) or irreducible; bowel sounds may be audible over it, and a tender, irreducible, erythematous hernia with vomiting or absolute constipation signals strangulation and is a surgical emergency. A haematocele presents as a tense, tender, ecchymotic swelling after trauma or a scrotal procedure and, unlike hydrocele, does not transilluminate. Idiopathic scrotal oedema, seen almost exclusively in prepubertal boys, produces fiery erythema and oedema confined to the scrotal wall and sometimes spreading to the perineum, groin, or contralateral hemiscrotum, but the underlying testis remains normal in size, lie, and consistency, is non-tender, and the cremasteric reflex is preserved; these normal testicular findings are what separate it from testicular torsion, which must always be the first diagnosis excluded whenever a boy presents with acute scrotal change.

4. Investigations and AU-specific cutoffs

Scrotal ultrasound with colour Doppler is the definitive investigation whenever the bedside algorithm cannot confidently exclude a testicular or retroperitoneal cause, and is mandatory in several specific circumstances. Any lump that is inseparable from the testis, solid or irregular on palpation, or non-transilluminating requires urgent ultrasound to exclude a testicular tumour, consistent with USANZ and RACGP guidance on scrotal masses and with HealthPathways WA referral criteria. A new or rapidly enlarging secondary hydrocele, particularly in a man under 40, requires ultrasound before it is assumed to be primary, because the fluid can mask an underlying tumour or epididymo-orchitis on palpation; needle aspiration of a suspicious hydrocele is discouraged as an initial step because it provides poor diagnostic yield and does not reliably exclude malignancy. Trauma with a tense, tender, non-transilluminating haematocele requires urgent ultrasound to assess the integrity of the tunica albuginea and exclude testicular rupture, because delayed diagnosis of rupture increases the rate of orchidectomy. A new right-sided varicocele, a varicocele on either side that fails to decompress when the patient lies supine, or an acute-onset varicocele in an older man is a red flag for retroperitoneal or renal pathology and warrants cross-sectional imaging of the abdomen and pelvis (CT with contrast, or renal-focused ultrasound as a first step where CT is not immediately available) to exclude a renal cell carcinoma extending into the renal vein or inferior vena cava, or retroperitoneal lymphadenopathy, in addition to scrotal ultrasound to characterise the varicocele itself.

Clinical varicocele is graded on standing examination: subclinical (grade 0) varicoceles are impalpable and detected only on Doppler ultrasound; grade 1 is palpable only during a Valsalva manoeuvre; grade 2 is palpable at rest without Valsalva but not visible; and grade 3 is visible through the scrotal skin without palpation. For men being investigated for subfertility with a palpable varicocele, semen analysis characterises the impact on sperm concentration, motility, and morphology; subclinical varicoceles detected only on ultrasound are not treated on fertility grounds, as evidence of benefit is confined to clinically palpable disease.

By contrast, ultrasound can reasonably be deferred in favour of reassurance where the clinical picture is unambiguous: a longstanding, stable, soft cystic swelling that is clearly separate from a normally palpable testis, transilluminates, and has none of the red-flag features above (for example, a typical epididymal cyst in an older man) can be managed on clinical grounds, although many clinicians still obtain a baseline scan at first presentation to document the diagnosis. Idiopathic scrotal oedema with a normal, non-tender testis and preserved cremasteric reflex can similarly be managed clinically without urgent imaging, provided the examination is unequivocal; any uncertainty about testicular torsion mandates urgent Doppler ultrasound, or immediate surgical exploration if clinical suspicion is high enough that imaging would only delay definitive treatment.

5. Management

Management follows directly from the cause. A primary hydrocele in an adult that is asymptomatic requires no treatment beyond reassurance; surgical hydrocelectomy (excision or plication of the tunica vaginalis) is reserved for hydroceles causing discomfort, cosmetic concern, or difficulty with hygiene or sexual function. A congenital communicating hydrocele in an infant is observed, as the great majority resolve spontaneously by 12 to 24 months of age as the processus vaginalis completes obliteration; persistence beyond about two years, or an associated hernia, is an indication for surgical ligation of the patent processus vaginalis through an inguinal approach, the same operation used for a paediatric inguinal hernia repair. A secondary hydrocele is managed by treating the underlying cause once ultrasound has characterised it.

Asymptomatic, low-grade varicocele with normal semen parameters and no fertility concerns does not require intervention. Varicocelectomy (surgical ligation of the dilated veins, most commonly by a microsurgical subinguinal or inguinal approach, which has the lowest rates of recurrence and of iatrogenic hydrocele compared with older open or laparoscopic techniques) or radiological percutaneous venous embolisation is indicated for a symptomatic varicocele causing persistent pain or heaviness unrelieved by scrotal support and simple analgesia, for a palpable varicocele in a man from a couple with otherwise unexplained subfertility and an abnormal semen analysis, or for ipsilateral testicular hypotrophy or growth arrest in an adolescent. A varicocele found to be secondary to a retroperitoneal or renal mass is managed by treating the underlying malignancy; the varicocele itself typically resolves once the venous obstruction is relieved.

An epididymal cyst or spermatocele that is asymptomatic is left alone; surgical excision is reserved for lesions causing significant discomfort and is used cautiously in men who have not completed their family, because dissection close to the epididymal tubules carries a small risk of obstructing sperm transport. A reducible, uncomplicated inguinoscrotal hernia is managed with elective surgical repair to prevent incarceration; an irreducible or strangulated hernia, or one with signs of bowel obstruction or ischaemia, requires emergency surgery. A small, non-tender haematocele without evidence of testicular rupture can be managed conservatively with analgesia, ice, and scrotal support; a large, tense haematocele, or any suspicion of testicular rupture on ultrasound, requires urgent surgical exploration and repair of the tunica albuginea to preserve testicular viability. Idiopathic scrotal oedema is self-limiting, typically resolving within one to a few days with rest, elevation, and simple analgesia; no specific therapy alters its course, but the diagnosis is only made once testicular torsion has been confidently excluded.

6. Pharmacology and AU PBS notes

Pharmacological therapy plays a limited, largely supportive role in benign scrotal masses, most of which are mechanical or structural problems addressed by observation or surgery rather than medication. Simple analgesia (paracetamol, and an NSAID such as ibuprofen where not contraindicated) and scrotal support are first-line for the discomfort of a symptomatic varicocele, a hydrocele, or idiopathic scrotal oedema, and for postoperative pain after hydrocelectomy or varicocelectomy. There is no PBS-listed medical therapy that reduces the size of a hydrocele, varicocele, epididymal cyst, or spermatocele; hormonal or other pharmacological approaches to varicocele have not demonstrated benefit over surgical or radiological correction and are not used in Australian practice. Where a scrotal mass is managed surgically, routine antibiotic prophylaxis is not required for clean elective procedures such as hydrocelectomy or varicocelectomy in the absence of specific risk factors, consistent with general surgical antibiotic prophylaxis principles for clean, non-implant scrotal surgery. Where epididymo-orchitis is suspected as an alternative or coexisting diagnosis, antibiotic choice is guided by the likely organism (doxycycline-based regimens for sexually transmitted causes in younger men, or agents covering Gram-negative organisms where a urinary source is likely), but that management pathway sits outside the scope of this benign-lump-focused topic.

7. Complications and monitoring

The most serious complication in this topic is not of the benign lumps themselves but of the diagnostic pathway: missing a testicular tumour because a reactive secondary hydrocele was assumed to be primary and not scanned, or missing a retroperitoneal or renal malignancy because a new right-sided or non-reducible varicocele was dismissed as an incidental finding. Conversely, over-investigating or over-treating unequivocally benign findings (for example, excising every incidental epididymal cyst) carries its own small but real risk, particularly epididymal duct injury and impaired fertility from unnecessary surgery close to the epididymis.

Recognised complications of surgical repair include recurrence (hydrocele recurrence after hydrocelectomy, and varicocele recurrence after varicocelectomy, both lowest with meticulous microsurgical technique), iatrogenic hydrocele formation after varicocelectomy from unrecognised lymphatic injury, wound infection and scrotal haematoma, and, rarely, testicular atrophy from inadvertent injury to the testicular artery during varicocele or hernia surgery. An untreated incarcerated inguinoscrotal hernia can progress to strangulation with bowel ischaemia, a surgical emergency. An untreated testicular rupture underlying a haematocele leads to progressive parenchymal necrosis and a substantially higher rate of orchidectomy the longer surgery is delayed, which is why any haematocele with suspected rupture on ultrasound is repaired urgently rather than observed.

Follow-up after varicocelectomy performed for subfertility includes a repeat semen analysis at approximately three months, chosen to allow a full spermatogenic cycle to elapse before improvement in sperm concentration and motility is assessed. Men managed conservatively for a clinically reassuring finding (a stable epididymal cyst, a low-grade asymptomatic varicocele) do not require routine surveillance imaging, but should be advised to return if the lump changes character, becomes painful, or the testis becomes difficult to palpate separately from it, prompting repeat clinical and ultrasound assessment.

Written for Australian practice and grounded in the guidance named above. Study material only — not medical advice. Always check against current guidelines.