Question:

A 70-year old retired worker had more than ten years of skin rash followed up in a skin clinic for management. He accidentally discovered multiple nodules over his scrotum in the past one year and became anxious because he was worrying about skin cancer or infection spreading to other regions. Occasionally, there was some discharge from these lesions and they were itchy to various degrees in the past one year. However, there was no generalized pruritus. There had been one episode of painful swelling in one of these lesions two months ago which responded rapidly to a course of systemic cloxacillin.

Answer: D. Epidermoid cyst

epidermoid cyst is the result of the proliferation of surface epidermal cells within the dermis. It presents as a dome-shaped protuberance of the skin. Some cysts may be tethered to the epidermis and there may be a central punctum representing the plugged orifice of the pilosebaceous follicle. Cheesy keratinous material may be expressed from this punctum. Cysts may appear yellowish or white when they are superficial. Some may become inflamed and secondarily infected. The condition is also called epidermal inclusion cyst, infundibular cyst, epithelial cyst, keratin cyst and sebaceous cyst. This is a benign condition and usually those cysts with history of repeated inflammation may need removal. However, ruptured, inflamed or infected cysts should not be immediately excised. It is best to let the inflammatory reaction subside a bit and the size of the cyst reduced before excision is attempted.

Scrotal calcinosis is a relatively common benign idiopathic disorder. Calcinosis of the scrotum will present as multiple firm grayish white and nodules scattered in the scrotal skin. Occasionally they may become secondarily inflamed or infected. They gradually increase in size and may break down to discharge the chalky contents. The blood calcium and phosphorus levels are normal. It is possible that the calcified nodules may arise from the epidermoid cysts. A skin biopsy can easily exclude the epidermoid cyst though both are benign conditions.

Angiokeratoma of Fordyce selectively involves the scrotal skin. They present clinically as small 1 to 4 mm bright red vascular discrete hyperkeratotic lesions. With increasing age of the patient, they will become larger, darker and increase in number. Itching, soreness or bleeding from lesions after scratching is not uncommon.

Bowenoid papulosis occurs in younger patient as multiple grouped papules with warty or smooth surface. It locates more often in the shaft of penis. It looks more brown red or hyperpigmented. They may be confused with genital wart, seborrhoeic wart or epidermal naevus. This condition is caused by the human papillomavirus type 16 infection.