Prostate
Granulomatous lesions
Nonspecific granulomatous prostatitis

Author: Ximing J. Yang, M.D., Ph.D. (see Authors page)

Revised: 27 December 2016, last major update December 2016

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PubMed Search: Nonspecific granulomatous prostatitis
Cite this page: Nonspecific granulomatous prostatitis. PathologyOutlines.com website. http://pathologyoutlines.com/topic/prostategranprost.html. Accessed May 22nd, 2017.
Definition / general
  • Granulomatous inflammation of the prostate not associated with specific causes such as biopsy, transurethral resection, TB, fungi infection or BCG treatment
  • Nonspecific granulomatous prostatitis (NSGP) is uncommon, present in less than 1% of prostate biopsies
  • However, it is the most common granulomatous inflammatory condition of the prostate, accounting for more than half of cases with prostatic granulomatous inflammation (Epstein: Biopsy Interpretation of the Prostate, 5th Edition, 2014)
Etiology
  • Nonspecific granulomatous prostatitis (NSGP) is most likely caused by the blockage of prostatic ducts (possibly due to benign prostatic hyperplasia) and associated inflammation, which can cause epithelial disruption and damage
  • The cellular debris and prostatic secretion leaking into the stroma induce a granulomatous inflammatory reaction, which is typically centered around the damaged ducts or acini (Fig 1)
Clinical features
Case reports
  • 66 year old man with hematuria, PSA of 14 ng / ml and a hard nodular prostate on digital rectal examination (nonpublished case, see Fig 6 below)
  • Nonspecific granulomatous prostatitis with calculous ductal ectasia and extensive Paneth cell-like epithelial metaplasia (APMIS 2005;113:564)
Treatment
  • Generally treated with antibiotics and steroids
  • Most patients respond well to this treatment (Int J Urol 2001;8:578)
Gross description
  • The prostate may be firm and nodular, but gross appearance is not specific
Microscopic (histologic) description
  • Non specific granulomatous prostatitis is generally a diffuse process
  • The inflammation is often present as poorly defined expansile nodular infiltrates, usually involving entire lobules (Fig 3)
  • In the later stage, fibrosis and chronic inflammation become prominent and giant cells are occasionally seen (Fig 4)
  • In the early phase, acute inflammation or microabscesses are present within the ducts or acini (Fig 1A)
  • This is followed by rupture and destruction of the epithelial lining and lymphohistiocytic reaction (Fig 1B and 1C)
  • Granulomas are composed predominantly of histiocytes, lymphocytes and plasma cells
  • These granulomas are typically poorly defined and noncaseating (Fig 1D)
  • Eosinophils, neutrophils and multinuclear giant cells are occasionally seen (Fig 2)
  • Cytologic atypia can be seen in the reactive glandular cells (Fig 5), which may resemble adenocarcinoma (Am J Clin Pathol 1991;95:330)
  • In rare cases, adenocarcinoma may coexist with NSGP (Ann Diagn Pathol 2004;8:242)
Microscopic (histologic) images

Images hosted on Pathout server:

Contributed by Ximing J. Yang, M.D. Ph.D.
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Figures 1A - D

Figure 2

Figure 3

Figure 4


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Figure 5

Figure 6A

Figure 6B



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Nonspecific granulomatous prostatitis