Angiokeratoma Circumscriptum 

Angiokeratomas are a group of vascular ectasias that involve the papillary dermis and may produce papillomatosis, acanthosis, and hyperkeratosis of the epidermis. Several clinical variants of angiokeratomas exist; angiokeratoma circumscriptum is one type, and the least frequent of the other types of angiokeratomas. Overall, 8 types of angiokeratomas have been described in the literature. The first reported case dates as far back as 1889 when Mibelli described what is now known as angiokeratoma Mibelli-type on the fingers and the toes. Fabry first described angiokeratoma circumscriptum in 1915 as a localized lesion on a lower extremity or the trunk. In addition, a rare manifestation of angiokeratoma circumscriptum naeviforme, with appearance on the neck, has been documented. These lesions are of clinical importance because they may clinically mimic a malignant melanoma.^[1]

In many cases, the lesions are present at birth, but they may appear in childhood or adulthood. Angiokeratoma circumscriptum has been reported to coexist with angiokeratoma of Fordyce^[2] (found on the scrotum) and caviar spots (angiokeratomas of the tongue).^[3] Other clinical associations include its occurrence with Cobb syndrome, Klippel-Trenaunay syndrome, nevus flammeus, cavernous hemangiomas, hemangiectatic hypertrophy,^[4] angiokeratoma corporis diffusum,^[5] and traumatic arteriovenous fistulas. Angiokeratoma circumscriptum has also been called angiokeratoma corporis naeviform and may be best classified as a type of capillary malformation.^{[6, 7]}

As Imperial and Helwig discussed in 1967, angiokeratomas are not true angiomas but rather telangiectasias of preexisting vessels.^[8] The mechanism for development of angiokeratoma circumscriptum is unknown. Several causal factors, such as congenital development, pregnancy, trauma, subcutaneous hematomas, and tissue asphyxia, have all been proposed.

Interestingly, lymphangioma circumscriptum, an entity that is microscopically similar to angiokeratoma circumscriptum, has been reported to occur in a setting of damaged deep lymphatic vessels. Unlike angiokeratoma of Mibelli or angiokeratoma corporis diffusum (Fabry disease), no pattern of inheritance or associated enzyme defect has been found for angiokeratoma circumscriptum. Overall, altered hemodynamics (typically caused by trauma) appear to produce telangiectatic vessels of the papillary dermis with an overlying reactive hyperkeratosis to the epidermis.^[9]

Frequency

United States

The frequency of angiokeratoma circumscriptum is unknown. However, it is probably more common than what the relatively few cases in the literature indicate. Because no associated systemic morbidity occurs, most cases remain clinically innocuous and go unreported.

Mortality/Morbidity

Angiokeratoma circumscriptum is a benign vessel ectasia involving the papillary dermis. No deaths from this entity have been reported. However, because it may clinically mimic a melanoma, morbidity may arise from attempts to render treatment for a melanoma before histologic verification is given. Furthermore, because angiokeratomata are vascular lesions, recurrent bleeding can occur. Life-threatening bleeding is not a concern, probably because of the small size of the affected vascular spaces.

Race

No ethnic predilection has been observed or reported to date.

Sex

Women are affected more commonly than men, in a ratio of approximately 3:1.

Age

Angiokeratoma circumscriptum may be either congenital or acquired. Lesions are commonly present at birth, but development in early childhood and even adulthood has been documented.