A type of angiokeratoma that most commonly occurs on the scrotum of patients who are 40 years old or older. The typical single lesion is a dark red to blue dome-shaped papule 2-4 mm in diameter with a very discrete keratotic surface. Typically, they are multiple and arranged in a line parallel to the raphe mediana of the scrotum. They also occur on the vulva and less commnly on the penis. [from
HPO]