Stains
Prostate specific antigen (PSA)

Author: Komal Arora, M.D. (see Authors page)

Revised: 15 December 2015, last major update April 2012

Copyright: (c) 2002-2015, PathologyOutlines.com, Inc.

PubMed Search: Prostate specific antigen [title]

Cite this page: Prostate specific antigen (PSA). PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/stainspsa.html. Accessed December 10th, 2016.
Definition / General
  • Kallikrein related serine protease produced by secretory epithelium, drains into ductal system
  • Cleaves and liquefies seminal coagulum formed after ejaculation
Clinical Features
  • Serum PSA > 4 seen in 80% with histologically documented cancer but also in 25 - 30% with nodular hyperplasia, prostatitis, infarcts, prostatic massage, cystoscopy
  • Elevated in 2 of 18 post-race marathon runners (Arch Pathol Lab Med 2003;127:345)
  • Serum PSA may be normal in prostatic duct carcinomas
  • Prostate carcinomas secrete 10x the PSA of normal tissue (in the past, 50% had levels > 10 mg/ml)
    • As a result, annual testing was traditionally recommended for men 50+ and men 40+ at increased risk
  • Routine screening using PSA with or without digital rectal exam does not significantly affect mortality overall or from prostate cancer (BMJ 2010;341:c4543), so unclear if modest benefit of reduced mortality outweighs the harms of overdetection and overtreatment (Ann Intern Med 2008;149:185, Curr Opin Urol 2010;20:185)
  • American College of Preventive Medicine does not recommend routine population screening with digital rectal exam or PSA (Am J Prev Med 2008;34:164)
  • Serial PSA measurements important for follow up
  • PSA can be performed in Point of Care setting (Clin Chim Acta 2009;406:18)
  • Related clinical tests: PSA density (PSA per volume of prostate gland), PSA velocity (changes in PSA with time), % free PSA (unbound PSA compared to alpha-1-antichymotrypsin)
  • Markers that may complement PSA in the early detection of prostate cancer include specific isoforms of PSA and PCA3
  • In patients with PSA >10 but no known prostatic carcinoma, soy isoflavones and curcumin reduced PSA levels (Prostate 2010;70:1127)
Uses by Pathologists
  • Glycoprotein detected in benign and malignant prostate tissue
    • Identifies prostatic origin of most metastatic tumors, differentiates between prostatic and urothelial carcinomas
    • Non-prostate tumors are usually weak / negative for PSA / PAP
  • PSA is more sensitive (intense, diffuse staining) and specific than PAP
Micro Images

Images hosted on Other severs:

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Bladder, ectopic prostate

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Prostatic adenocarcinoma, comparison to NKX3.1, PSAP

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Prostatic adenocarcinoma

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Prostatic duct carcinoma

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Prostate: neuroendocrine carcinoma is PSA+

Positive Staining - Normal
  • Prostatic epithelium
Positive Staining - Disease
Negative Staining
  • Nephrogenic adenoma, prostatic adenoid basal tumor, adenosquamous, clear cell, small cell and squamous cell carcinomas