title: Parapharyngeal neoplasm of mixed mesenchymal and neuroepithelial origin.
abstract: 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.
mesh_terms: D000328:Adult; D003937:Diagnosis, Differential; D005354:Fibrosarcoma / Q000473:pathology; D005729:Ganglioneuroma / Q000473:pathology; D006258:Head and Neck Neoplasms / Q000473:pathology*; D006801:Humans; D008297:Male; D008579:Meningioma / Q000473:pathology; D009373:Neoplasms, Germ Cell and Embryonal / Q000175:diagnosis / Q000473:pathology*; D009432:Neural Crest; D012208:Rhabdomyosarcoma / Q000473:pathology; D013724:Teratoma / Q000175:diagnosis