What are the possible causes and treatments for a lump over the inguinal area?

Inguinal Lump: Differential Diagnosis and Management

An inguinal lump requires immediate evaluation to distinguish between benign causes (inguinal hernia, reactive lymphadenopathy) and serious conditions requiring urgent treatment (malignancy, sexually transmitted infections like lymphogranuloma venereum, or penile cancer metastases).

Initial Clinical Assessment

Key History Elements

• Duration and progression: Rapid growth over days suggests infection or aggressive malignancy 1, while chronic lumps (months to years) may indicate hernia, endometriosis, or indolent malignancy 2
• Pain characteristics: Painless lumps suggest granuloma inguinale or malignancy 3, while tender lumps indicate lymphogranuloma venereum (LGV) or reactive lymphadenopathy 4
• Cyclic symptoms: Pain or size changes with menstruation in women suggests inguinal endometriosis 2
• Sexual history: Recent unprotected sexual contact raises concern for LGV or granuloma inguinale 4
• Associated symptoms: Genital ulcers, discharge, bleeding, or dysuria point toward sexually transmitted infections or penile cancer 4

Physical Examination Findings

• Unilateral tender inguinal/femoral lymphadenopathy in men suggests LGV 4
• Painless, progressive ulcerative lesions with "beefy red appearance" that bleed easily indicate granuloma inguinale 4, 3
• Fixed or matted lymph nodes raise concern for metastatic penile cancer 4
• Reducible mass that increases with Valsalva suggests inguinal hernia 5

Critical pitfall: Physical examination alone has only 82% sensitivity and 79% specificity for inguinal lymph node disease, incorrectly staging 26% of cases 4

Diagnostic Approach

For Suspected Sexually Transmitted Infections

Lymphogranuloma Venereum (LGV):

• Diagnosis is primarily serological and by exclusion of other causes 4
• Treat immediately with doxycycline 100 mg orally twice daily for 21 days 4
• Alternative: Erythromycin base 500 mg orally four times daily for 21 days (for pregnant women) 4
• Buboes may require aspiration through intact skin or incision and drainage 4

Granuloma Inguinale:

• Diagnosis requires visualization of Donovan bodies on tissue crush preparation or biopsy using Wright or Giemsa stain 3
• Scraping should be from lesion base, avoiding necrotic areas 3
• Treat with trimethoprim-sulfamethoxazole one double-strength tablet orally twice daily for minimum 3 weeks 4
• Alternative: Doxycycline 100 mg orally twice daily for minimum 3 weeks 4
• Continue therapy until complete healing 4
• Add gentamicin 1 mg/kg IV every 8 hours if no response within first few days 4

For Suspected Malignancy

When penile lesion is present:

• Obtain punch, excisional, or incisional biopsy of primary lesion 4
• MRI or ultrasound to define extent of primary tumor 4
• For palpable inguinal nodes: Fine-needle aspiration regardless of mobility 4
• If FNA negative, confirm with excisional biopsy 4

When isolated inguinal mass without genital lesion:

• Ultrasound as first-line imaging 5, 2
• CT or MRI if ultrasound inconclusive, especially in obese patients 4
• Excisional biopsy for definitive diagnosis 1, 2

Treatment Based on Diagnosis

Inguinal Hernia

• Surgical repair with mesh reinforcement 2, 6
• Watch for postoperative lymphocele, which may require negative pressure wound therapy 6

Malignant Lymphoma

• Requires adequate tissue for histopathological evaluation 1
• CHOP-R regimen for diffuse large B-cell lymphoma with >50% disease-free survival 1

Penile Cancer Metastases

• For N2-N3 disease: bilateral inguinal lymphadenectomy 4
• Consider neoadjuvant cisplatin-based chemotherapy for bulky nodes 4
• Pelvic lymph node dissection if ≥2 inguinal nodes positive on frozen section 4

Inguinal Endometriosis

• Surgical excision with safety margin and mesh repair 2
• Consider in nulliparous women with cyclic pain 2

Red Flags Requiring Urgent Evaluation

• Rapid growth over days to weeks suggests aggressive lymphoma or infection 1
• Fixed or matted lymph nodes indicate advanced malignancy 4
• Painless progressive ulceration requires biopsy to exclude granuloma inguinale 4, 3
• Bilateral involvement increases likelihood of metastatic disease 4

Follow-Up Strategy

• For treated STIs: Clinical follow-up until complete resolution 4
• For malignancy: Intensive surveillance with clinical exam every 3 months for years 1-2, then every 6 months for years 3-5 4
• Post-surgical: Monitor for wound complications, lymphedema, and lymphocele 4, 6