Intravascular papillary endothelial hyperplasia (IPEH)
is a benign overgrowth of endothelial cells (the cells lining blood vessels). The most frequent sites for IPEH are the deep vascular inner layers of skin (dermis and subcutis) of the head and neck regions and in the lip, tongue and buccal mucosa. Rare locations include the thyroid, eye (orbit), parotid gland, muscles involved in chewing (masseter muscle), nose, sinus, mandible, pharynx and central nervous system. The average age of onset is 34. Signs and symptoms depend on the location of the IPEH. A definitive diagnosis is made by biopsy of the tumor and examination of the specimen by a pathologist. Treatment usually involves removal of the tumor by surgery. Recurrences are very rare. Source: Genetic and Rare Diseases Information Center (GARD), supported by ORDR-NCATS and NHGRI.