Other malignancies
Primitive peripheral neuroectodermal tumor / PNET

Authors: Kenneth Iczkowski, M.D. (see Authors page)

Revised: 22 October 2017, last major update October 2017

Copyright: (c) 2003-2017,, Inc.

PubMed Search: prostatic primitive peripheral neuroectodermal tumor

Related Topics: Kidney tumor

Cite this page: Iczkowski, K. Primitive peripheral neuroectodermal tumor / PNET. website. Accessed November 20th, 2017.
Definition / general
Essential features
  • A neural crest tumor of young people
  • Belongs to the Ewing family of tumors
  • A type of small round blue cell tumor
  • This tumor usually involves children and young adults
Clinical features
  • All cases reported presented with dysuria and pelvic discomfort
Case reports
  • Chemotherapy, with or without surgery
  • Treatment with chemotherapy and radiotherapy without surgery may be successful (J Cancer Res Ther 2015;11:668)
Microscopic (histologic) description
  • Solid nests and sheets of small round cells
Microscopic (histologic) images
Images hosted on other servers:

Various images

25 year old man

Tumor cells (a) are positive for (b) CD99
(c) BCL2, (d) and pan cytokeratin

Negative stains
Molecular / cytogenetics description
  • Fluorescence in situ hybridization using EWSR1 (22q12) dual color, break apart probe, showing rearrangement of Ewing sarcoma region on chromosome 22, causing t(11, 22) (q24, q12) in 90% of cases (Indian J Pathol Microbiol 2012;55:569)
  • Polymerase chain reaction and sequencing shows EWS / FLI1 type 2 chimeric transcript which is confirmatory
Differential diagnosis
Board review question #1
Positive stains for prostatic PNET include all except:

A. Broad spectrum cytokeratin
B. S100
C. CD99 / MIC2
Board review answer #1
B. S100