Parapharyngeal neoplasm of mixed mesenchymal and neuroepithelial origin

A 20-year-old man had a left parapharyngeal neoplasm that displayed features of sarcoma of the nerve sheath, meningioma with an osseous component, rhabdomyosarcoma, and ganglioneuroma. The diverse cellular population suggests a tumor origin from the ectomesenchymal remnants of the neural crest. The mesenchymal part of the crest would differentiate into a variety of mesenchymal neoplastic elements, and the neuroectodermal (neuroepithelial) portion into the ganglioneuroma. These various neoplastic constituents then would form a neoplasm of mixed mesenchymal and neuroepithelial origin, or an ectomesenchymoma.