The term myoblastic myoma was first used in 1926 by Abrikossoff1 to designate a group of peculiar tumors which he interpreted as being derived from primitive myoblasts, which were thought to develop during the process of regenerative changes after muscle injury. In 1928, Klinge2 reported 2 cases of this condition in the skin unrelated to striated muscle. To explain this, a dysontogenetic theory was suggested. This theory depended on the abnormal inclusion of potential muscle-building cells which migrate out from the primitive dermomyotome along with the tissue destined to form the corium of the skin. Fräsdorf,3 in 1939, described an instance of a pair of myoblastomas located in the pharynx of a 68 year old man who also had several other malformations. He felt that the bilateral character of the tumor formations, together with other malformations, substantiated the dysontogenetic basis of the histogenesis of the tumor. In