Acanthoma is a type of skin tumor. The name, derived from a Greek word meaning thorn, refers to the hardening and thickening of the skin cells that form the lesions. One type, acanthoma adenoides cysticum (also called Brooke tumor, multiple benign cystic epithelioma, or epithelioma adenoides cysticum), occurs in childhood, adolescence, or adulthood. The condition is inherited. Flesh colored, pink or bluish lesions, pinhead sized or larger, appear on face, neck, and chest. They are symmetrically ar- ranged, often appear close together, and probably originate in hair follicles.
The other type of acanthoma, known as senile keratosis or solar keratosis, is associated not so much with old age as with degree of exposure to the sun and/or radiation. Lesions appear on exposed surfaces, mostly the face, neck, ears, and chest; they are rough, horny elevations, gray, brown, or black, a millimeter to a centimeter in diameter. The lesions are precancerous and, when they become malignant, they show red friable tissue at margins and base. Electrolysis, electrodesiccation, or excision are used to remove lesions in both types of acanthoma.