Mediastinum
Other malignancies
Primitive neuroectodermal tumor (PNET)



Topic Completed: 1 December 2012

Revised: 14 February 2019

Copyright: 2003-2018, PathologyOutlines.com, Inc.

PubMed Search: Primitive neuroectodermal tumor mediastinum

Hanni Gulwani, M.B.B.S.
Page views in 2018: 389
Page views in 2019 to date: 551
Cite this page: Gulwani H. Primitive neuroectodermal tumor (PNET). PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/mediastinumPNET.html. Accessed July 21st, 2019.
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
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