A rare benign (not cancer) tumor of small blood vessels surrounded by lymphocytes and eosinophils (types of white blood cells). Histiocytoid hemangioma usually forms on or in the skin, especially the skin of the head, but can occur in other areas of the body, such as in bone. On the skin, it may appear as firm pink to red bumps that may be itchy or painful. If the tumor is in bone, it may cause swelling and pain. Histiocytoid hemangioma is sometimes caused by injury and often comes back after treatment. Histiocytoid hemangioma is most common in young and middle-aged adults. It is a type of vascular tumor. Also called angiolymphoid hyperplasia with eosinophilia and epithelioid hemangioma.