Idiopathic Scrotal Calcinosis

Idiopathic scrotal calcinosis is a benign condition with multiple painless calcified nodules in the scrotal skin and subcutaneous tissue, occurring without a metabolic disorder or preceding tissue injury.

It usually begins in young men, between the late teens and the third decade, and the nodules slowly increase in number and size.

It causes no harm to the testes and has no malignant potential. The main concerns are appearance, itching, ulceration and infection.

Pathophysiology. The leading explanation is dystrophic calcification of degenerating epidermal or eccrine cyst contents, with a surrounding foreign body giant cell reaction. Serum calcium, phosphate, parathyroid hormone and vitamin D are normal.

Calcinosis cutis from a metabolic or connective tissue disorder must be excluded: hypercalcaemia, hyperphosphataemia, chronic kidney disease, vitamin D excess, systemic sclerosis, dermatomyositis and lupus.

Multiple firm, yellow white, painless nodules in the scrotal skin, from 1 mm to 3 cm, that do not move with the testis. Some ulcerate and discharge chalky material, itch, or become infected. The testes and epididymis are normal. Onset is gradual, and many men present only because of embarrassment or discharge.

• Clinical diagnosis in typical cases.
• Serum calcium, phosphate, parathyroid hormone, 25-hydroxyvitamin D, creatinine and alkaline phosphatase to exclude metabolic disease. Antinuclear antibodies when connective tissue disease is suspected.
• Scrotal ultrasound: hyperechoic foci with posterior acoustic shadowing in the scrotal wall, with normal testes. Plain film or CT also shows the nodules.
• Excision biopsy with histology: calcium deposits in the dermis, positive on von Kossa stain, with a granulomatous foreign body reaction.
• Sexually transmitted infection and tuberculosis tests when ulcers or sinuses are present.

Differential diagnosis.

• Epidermoid (sebaceous) cysts
• Calcinosis cutis from metabolic or connective tissue disease
• Pilomatricoma
• Genital warts and molluscum contagiosum
• Tuberculous or syphilitic lesions
• Calcified parasitic cysts (cysticercosis, schistosomiasis)
• Scrotal pearls (loose fibrinous bodies)
• Lymphoedema papules

• Asymptomatic or few nodules: reassurance and observation.
• No drug treatment has proven benefit. Diltiazem, etidronate, warfarin and topical sodium thiosulphate have been used in case reports.
• Surgery for symptoms, infection or cosmetic distress:
  • Excision of individual nodules under local anaesthesia with lidocaine 1% (maximum 4.5 mg/kg without adrenaline, or 7 mg/kg with adrenaline), and curettage of chalky material.
  • Wide excision of the affected scrotal skin with primary closure, which is possible because scrotal skin is lax. Complete excision lowers recurrence, and incomplete excision is followed by new or residual lesions.
• Infected nodules: flucloxacillin 500 mg orally four times daily for 7 days, adjusted to culture. Penicillin allergy: clarithromycin 500 mg orally twice daily for 7 days.
• Perioperative cefazolin 2 g intravenously (3 g if over 120 kg) as a single dose for wide excision.
• Complications: wound infection, haematoma, scarring and recurrence.

Monitoring. Wound review at 2 weeks, with reassessment at 3 months and yearly for new lesions.

Referral and escalation. Refer to urology or dermatology for extensive disease, infection, or diagnostic doubt. Urgent referral is rarely needed, except for spreading infection.