What is the differential diagnosis and management for a lump on the scrotum?

Differential Diagnosis for a Scrotal Lump

Any solid mass within the testis should be managed as malignant until proven otherwise, requiring urgent scrotal ultrasound and serum tumor markers (AFP, β-HCG, LDH) before any intervention. 1

Initial Diagnostic Approach

Scrotal ultrasound with Doppler is the mandatory first-line imaging study to determine whether the lump is intratesticular (90% malignant) or extratesticular (usually benign). 1, 2

Key Clinical Distinction

• Intratesticular masses: Approximately 90% are malignant, most commonly germ cell tumors (seminoma 50%, non-seminoma 50%). 1, 2
• Extratesticular masses: Usually benign conditions. 2

Differential Diagnosis by Location

Intratesticular Masses (High Malignancy Risk)

Testicular germ cell tumors are the most common malignancy in men aged 15-40 years, with excellent cure rates (nearly 100% in stage I disease). 1

• Risk factors to assess: Cryptorchidism (RR 3.18), hypospadias (RR 2.41), inguinal hernia (RR 1.37), testicular atrophy (<12 ml volume), family history. 1, 3
• Important caveat: Testicular microlithiasis alone without solid mass or other risk factors does NOT increase malignancy risk and requires no further evaluation. 1

Extratesticular Masses (Usually Benign)

The most common benign findings include:

• Epididymal cysts/spermatoceles: Most common finding (27% of scrotal lumps in primary care). 2
• Hydrocele: Fluid collection between tunica vaginalis layers (11% of cases). 2
  • Red flag: Hydrocele in men aged 20-40 requires urgent ultrasound to exclude underlying testicular pathology. 2
• Varicocele: Dilated veins that become more prominent when standing, less noticeable when supine. 4
• Inguinal hernia: Intermittent lump that changes with position or Valsalva maneuver. 4
• Scrotal wall leiomyoma: Rare benign tumor arising from dartos muscle layer, typically firm and mobile. 5
• Supernumerary testicle: Extremely rare congenital anomaly. 6

Acute/Inflammatory Conditions

• Epididymitis/epididymo-orchitis: Infectious etiology with pain and swelling. 7
• Testicular torsion: Surgical emergency presenting with acute pain (may have intermittent episodes). 4, 7
• Testicular trauma/rupture: Requires immediate surgical evaluation. 7
• Fournier gangrene: Life-threatening necrotizing infection requiring emergency surgery. 7

Management Algorithm

Step 1: Immediate Workup for Any Scrotal Mass

1. Draw serum tumor markers BEFORE any intervention (including orchiectomy): AFP, β-HCG, LDH. 1
2. Obtain scrotal ultrasound with Doppler (7.5 MHz transducer) to characterize the mass and assess both testes. 1
3. Counsel about fertility preservation and offer sperm banking before any definitive treatment. 1

Step 2: Management Based on Ultrasound Findings

For solid intratesticular mass:

• Radical inguinal orchiectomy is the standard of care and should be performed urgently. 1, 8
• Critical surgical principle: Use inguinal approach only—scrotal violation must be avoided as it increases local recurrence risk. 1, 2
• Consider intraoperative frozen section for small tumors (<2 cm) to allow testis-sparing surgery in select cases. 1

For indeterminate findings with normal tumor markers:

• Repeat imaging in 6-8 weeks. 1

For extratesticular masses:

• Most can be managed conservatively or with simple excision. 2, 5
• Hydrocele in young men (20-40 years) requires urgent ultrasound to exclude underlying malignancy. 2

Step 3: Post-Orchiectomy Staging (if malignancy confirmed)

• Repeat tumor markers 7 days post-surgery to assess half-life kinetics. 1
• CT chest, abdomen, and pelvis for staging. 1
• Full blood count, renal function, liver enzymes. 1

Critical Pitfalls to Avoid

• Never perform scrotal approach biopsy or surgery for suspected testicular tumors—this violates lymphatic drainage patterns and increases recurrence. 1, 2
• Do not delay evaluation of persistent testicular enlargement—delay correlates with higher stage at presentation. 8
• Always obtain tumor markers BEFORE orchiectomy—they are essential for staging and monitoring. 1
• Do not assume testicular microlithiasis alone requires follow-up—it only increases risk when other risk factors are present. 1
• Do not forget fertility counseling and sperm banking before any treatment that may compromise fertility. 1, 8
• Urgent ultrasound is mandatory for hydrocele in men aged 20-40 to exclude underlying testicular cancer. 2