A 14-year-old girl presented with several years history for an asymptomatic lesion on her flank. She had not any other significant medical problem.
What is your diagnosis?
Diagnosis: Angiokeratoma (AK)
Comment by; M. Mehravaran, MD, Dermatologist/ Szeged, Hungary:
The angiokeratomas are a group of benign vascular neoplasms in which marked dilated, thin-walled vessels are situated beneath hyperplastic and hyperkeratotic epidermis.
The Quiz case is an Solitary Angikeratoma, which descibes by Imperial and Helwig1 in 1967, this type of AK is a single small, bluish black, warty papule which occurs predominantly on the lower extremities (Quiz case is located in flank). It is not a hereditary lesions and probably follows trauma, which subsequent telangiectasia prior to formation of the AK. The mode of acquiring this lesions, the small size, its solitary nature, and its location distinguish it from the other forms of angiokeratomas. It should be differentiate from seborrheic keratosis, melanoma, pigmented basal cell carcinoma, pyogenic granuloma and ordinary hemangima.
There are several clinical types of angiokeratoma,
In solitary AK, there is well-circumscribed dark red, scaly papule of at least 0.5 mm diameter, which is often found on the leg.
Multiple lesions of similar appearance can sometimes occur. Thrombosis of superficial vessels of an AK cause the lesion to appear black, simulating melanoma.
AK of Mibelli largely occurs as small multiple lesions on the skin of the dorsal toes (and sometimes fingers) in patients with cold intolerance and sometimes, perniosis.
AK of Fordyce affects scrotal or vulvar skin and, sometimes, that of the adjacent abdomen or thight. This also features multiple lesions.
AK corporis diffusum is a component of several metabolic diseases, including Fabry's disease (X-linked recessive alfa-galactosidase, A deficiency disease that results in ceramide trihexidose accumulation in several organs).
AK circusmscriptum is a rare condition in which a solitary plaque composed of contiguous papular AK occupies a large area of skin.
Sections of all of the various AK shows a combination of thin-walled, ectatic vascular spaces that contain erythrocytes and epidermal hyperplasia with compact hyperkeratosis.
Thrombosed Aks are often so dark in color that they are suspected of being melanoma. AK of Mebelli can sometimes be difficult to distinguish from cryoglobulinemia or perniosis, but its lesions are more sharply circumscribed. The epidermal changes of AK histologically resemble those of verrucous hemangioma, a congenital lesion in which vessels are present throughout the thickness of the dermis.
Solitary AK are cured by simple excision. Multiple angiokeratoma can be excisied, frozen, electrodesiccated, or treated with laser.
1. Imerial R et al: Angiokeratoma. Arch dermatol 1967,95:166.
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