Prostate gland & seminal vesicles
Other malignancies

Topic Completed: 1 October 2017

Minor changes: 13 July 2020

Copyright: 2003-2019,, Inc.

PubMed Search: Prostatic primitive peripheral neuroectodermal tumor

Related Topics: Kidney tumor

Kenneth A. Iczkowski, M.D.
Page views in 2019: 394
Page views in 2020 to date: 358
Cite this page: Iczkowski KA. PNET. website. Accessed August 14th, 2020.
Definition / general
  • Primarily a tumor of soft tissue and bone
  • Belongs to the Ewing sarcoma family of tumors
  • Neural crest tumor of young people
  • Type of small round blue cell tumor
Essential features
  • Reported age range of 20 - 49 years
Clinical features
  • All cases reported presented with dysuria and pelvic discomfort or anal distention
Radiology description
  • Large and infiltrative soft tissue mass with an ill defined, necrotic region and heterogeneous enhancement¬†
Prognostic factors
Case reports
  • Multimodal treatment includes 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

Contributed by Kenneth A. Iczkowski, M.D.

Partly necrotic




Images hosted on other servers:

Various images

25 year old man

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

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)
  • Variant translocations involving chromosome 22q12, chromosome 21q22 (10% of Ewing sarcoma) and chromosomes 7q22, 17q12 and 2q36 (< 1% of Ewing sarcoma)¬†can occur
  • Polymerase chain reaction and sequencing shows EWS / FLI1 type 2 chimeric transcript which is confirmatory
Differential diagnosis
Board review style question #1
Positive stains for prostatic PNET include all except:

  1. BCL2
  2. Broad spectrum cytokeratin
  3. CD99 / MIC2
  4. S100
Board review answer #1
D. S100

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