Ectomesenchymal Hamartoma (Benign ectomesenchymoma ) of the VIIIth Nerve: Case Report

Abstract

WE REPORT A previously undescribed hamartoma of the VIIIth nerve, consisting of adipose tissue, Schwann cells associated with myelinated nerve fibers, well-differentiated smooth and striated muscle fibers, and rare ganglion cells. The tumor was found in a 35-year-old Caucasian female who presented with right-sided hearing loss. The mass, which we designate an “ectomesenchymal†hamartoma, most likely developed from pluripotent neural crest cells (“ectomesenchymeâ€), which are capable of differentiating into a variety of neuroectodermal and mesenchymal cell types. The development of the neural crest, the concept of “ectomesenchyme,†and the histogenesis of this tumor are reviewed. Copyright © by the Congress of Neurological Surgeons