Other benign / low grade tumors

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

Revised: 19 June 2018, last major update December 2012

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

PubMed Search: Schwannoma[TI] mediastinum

Cite this page: Gulwani, H. Schwannoma. website. Accessed September 21st, 2018.
Definition / general
  • Usually in posterior mediastinum, asymptomatic
  • Most common mediastinal neurogenic tumor
  • May present with symptoms of esophageal or nerve root compression
  • Benign
  • Also called neurilemoma
  • Usually in young adults
Case reports
  • Excision is almost always curative
Gross description
  • Encapsulated and sharply demarcated from adjacent soft tissue
  • May appear to "hang" from large nerves
  • Usually yellow cut surface, rarely dark red / black due to hemorrhage
  • Degenerative changes common (fat, hemorrhage, cysts)
Gross images

Images hosted on other servers:

51 year old man

Microscopic (histologic) description
  • Biphasic pattern of fusiform cells
  • Cellular areas with nuclear pallisading (Antoni A) and Verocay bodies and myxoid areas with only occasional cells (Antoni B)
  • Prominent thick walled blood vessels
  • No / rare mitotic figures
  • Ancient change: cystic changes, marked nuclear atypia but no mitotic figures
  • Cellular: densely cellular with herringbone, storiform or fascicular growth patterns, mild nuclear atypia, brisk mitotic activity but no necrosis, no atypical mitotic figures (unlike MPNST or other sarcomas)
  • Glandular: epithelial differentiation is focally present
  • Melanotic: pigment present
  • Psammomatous-melanotic: psammomatous calcification and pigment are present
Microscopic (histologic) images

Images hosted on other servers:

Antoni A

Antoni B

Electron microscopy description
Ancient change / ancient schwannoma:
  • Neural differentiation with elongated overlapping cell processes
  • Primitive junctions may resemble mesaxons
  • Abundant pericellular basal lamina