Prostate gland & seminal vesicles
Inflammation
Nonspecific granulomatous prostatitis
Author: Ximing J. Yang, M.D., Ph.D.
Topic Completed: 1 December 2016
Minor changes: 3 September 2020
Copyright: 2003-2021, PathologyOutlines.com, Inc.
PubMed Search: Nonspecific granulomatous prostatitis
Table of Contents
Definition / general | Etiology | Clinical features | Case reports | Treatment | Gross description | Microscopic (histologic) description | Microscopic (histologic) imagesCite this page: Yang XJ. Nonspecific granulomatous prostatitis. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/prostategranprost.html. Accessed May 15th, 2021.
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
- May be highly suspicious for prostate cancer
- Serum PSA is frequently elevated, up to 10 - 15 ng / ml (Arch Pathol Lab Med 1997;121:724)
- ~50% are symptomatic with irritation, fever or chills
- Some patients have symptoms of urinary obstruction or hematuria (Epstein: Biopsy Interpretation of the Prostate, 5th Edition, 2014)
- Prostate is hard and nodular on digital rectal examination
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
Contributed by Ximing J. Yang, M.D., Ph.D.
Figures 1A - D
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6A
Figure 6B
