Scrotal Lymphoedema

Scrotal lymphoedema is chronic swelling of the scrotal and penile skin from impaired lymph drainage, with protein rich fluid collecting in the dermis and subcutaneous tissue.

Advanced disease leads to scrotal elephantiasis, with thickened, warty skin and a massive scrotum.

Filariasis from Wuchereria bancrofti remains a leading cause in endemic regions, including the Kenyan coast. In non-endemic regions, obesity, recurrent infection and cancer treatment are the main causes.

Pathophysiology. Lymphatic obstruction or failure causes stasis, which provokes inflammation, fibrosis and fat deposition. Recurrent cellulitis, mainly streptococcal and staphylococcal, further scars the lymphatics.

Causes:

• Filariasis: adult worms damage lymphatics, causing hydrocele, lymph scrotum and elephantiasis over 10 to 15 years.
• Obesity (very high body mass index), and chronic venous insufficiency.
• Recurrent cellulitis and lymphangitis.
• Inguinal or pelvic lymph node dissection and radiotherapy, pelvic cancer, lymphoma and metastases.
• Tuberculosis, lymphogranuloma venereum, hidradenitis suppurativa and Crohn disease.
• Primary lymphoedema (Milroy disease, lymphoedema praecox), which is rare.
• Generalised oedema from heart, liver or kidney failure, or low albumin.

Painless swelling of the scrotal and penile skin that progresses over months to years, with tight, thick, peau d'orange skin, papillomatosis, lymph vesicles and leakage (lymphorrhoea), and sometimes a buried penis, difficulty voiding and sexual dysfunction. The testes are usually normal in size. Filariasis may also cause hydrocele, chyluria, acute funiculitis and epididymo orchitis, and limb lymphoedema.

Episodes of cellulitis (fever, rigors, red, painful skin) are common and worsen the disease. Rapid spread, skin crepitus or dusky skin suggests necrotising infection, and needs emergency treatment.

• History of residence in an endemic area, previous infection, surgery, radiotherapy and weight gain. Staging by clinical severity.
• Full blood count, C-reactive protein, glucose, creatinine, albumin, liver and thyroid function, and urinalysis for proteinuria and chyluria.
• Scrotal ultrasound: skin thickening, a cobblestone pattern, dilated lymphatics, normal testes, and in filariasis the filarial dance sign of moving worms.
• Filariasis tests: circulating filarial antigen by immunochromatographic card or ELISA, thick blood film for microfilariae taken between 10 pm and 2 am, and polymerase chain reaction. Many patients with established lymphoedema have no microfilariae, so antigen testing is preferred. Test for Loa loa where co-endemic before giving diethylcarbamazine or ivermectin.
• Imaging for the cause: CT or MRI of the pelvis and groin for masses or nodes, and lymphoscintigraphy or MR lymphangiography to map lymphatic function.
• Skin biopsy for atypical or non-healing lesions (squamous cell carcinoma and angiosarcoma are rare complications). HIV, syphilis and lymphogranuloma venereum testing as indicated.

Differential diagnosis.

• Hydrocele
• Acute idiopathic scrotal oedema
• Scrotal cellulitis and Fournier gangrene
• Inguinal hernia
• Scrotal calcinosis
• Hidradenitis suppurativa
• Lymphocele or lymphangioma
• Scrotal tumour
• Systemic oedema

• Skin care: wash daily with soap and water, dry thoroughly, apply emollient, and treat intertrigo and fungal infection with clotrimazole 1% cream twice daily for 2 to 4 weeks. Avoid trauma and tight, occlusive clothing.
• Decongestive therapy by a lymphoedema therapist: scrotal support and compression garments, manual lymphatic drainage, exercise, and weight loss. Diuretics are not effective.
• Acute cellulitis: flucloxacillin 500 mg to 1 g orally four times daily for 7 to 14 days. Penicillin allergy: clarithromycin 500 mg orally twice daily or doxycycline 200 mg on day 1 then 100 mg twice daily. Severe or systemic: flucloxacillin 2 g intravenously every 6 hours (or ceftriaxone 2 g intravenously once daily), adding vancomycin 15 mg/kg intravenously every 12 hours when meticillin resistant Staphylococcus aureus is possible.
• Prophylaxis after 2 or more episodes in a year: phenoxymethylpenicillin 250 to 500 mg orally twice daily for at least 6 to 12 months, or benzathine benzylpenicillin 1.2 million units intramuscularly every 3 to 4 weeks. Penicillin allergy: erythromycin 250 mg twice daily.
• Filarial disease:
  • Doxycycline 200 mg orally once daily for 4 to 6 weeks, which damages adult worms and improves early lymphoedema.
  • Albendazole 400 mg orally with diethylcarbamazine 6 mg/kg orally, as a single dose, or diethylcarbamazine for 12 days for an individual. Avoid diethylcarbamazine in pregnancy and where Loa loa or onchocerciasis is present, because of severe reactions. Mass drug administration programmes use a combination of ivermectin, diethylcarbamazine and albendazole.
  • Hydrocele repair by hydrocelectomy.
• Surgery for advanced disease: excision of diseased scrotal skin and subcutaneous tissue with preservation of the testes and penile skin, with split thickness skin graft or primary closure. Lymphovenous anastomosis or lymph node transfer is selected for early stages, and liposuction for fatty predominant disease. Perioperative cefazolin 2 g intravenously (3 g if over 120 kg) as a single dose.
• Treat underlying causes: weight loss, heart, kidney and liver failure, tuberculosis and malignancy.
• Complications of surgery: infection, wound breakdown, graft loss and recurrence.

Special groups. Pregnancy: avoid diethylcarbamazine and doxycycline, and treat after delivery. Boys and men from endemic areas need community treatment, with screening for hydrocele.

Monitoring. Review every 3 months in the first year for skin integrity, infection episodes and volume. Biopsy any non-healing, ulcerated or raised lesion. Repeat filarial antigen at 12 months after treatment.

Referral and escalation. Refer to urology, plastic surgery or a lymphoedema service, and to infectious disease for filariasis. Urgent referral for cellulitis with systemic features, suspected necrotising infection, or a suspicious mass.