Other malignancies
Primitive neuroectodermal tumor (PNET)

Author: Hanni Gulwani, M.D. (see Authors page)

Revised: 22 June 2018, last major update December 2012

Copyright: (c) 2003-2018,, Inc.

PubMed Search: Primitive neuroectodermal tumor mediastinum

Cite this page: Gulwani, H. Primitive neuroectodermal tumor (PNET). website. Accessed July 19th, 2018.
Definition / general
  • Rapidly growing mass in anterior or posterior mediastinum
  • Usually children
Case reports
Gross description
  • Bulky, poorly circumscribed, gray-white, fleshy, may adhere to spinal nerve root if in posterior mediastinum
Microscopic (histologic) description
  • Primitive round cell sarcoma that may have vaguely organoid pattern or primitive rosettes
  • Prominent network of intratumoral blood vessels
  • No cytoplasmic neurofibrillary maturation
  • May have rhabdomyosarcomatous areas or primitive glandular areas
Microscopic (histologic) images

Images hosted on other servers:

Site unspecified

Negative stains
Electron microscopy description
  • Blunt and rudimentary cytoplasmic processes
  • No intracellular microtubules, no / sparse synaptic vesicles or neurosecretory granules
  • Primitive intercellular junctions
Molecular / cytogenetics description
  • t(11;22)(q24;q12)
Differential diagnosis