What is Proliferative Inflammatory Atrophy?

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Chances are you’ve never heard of proliferative inflammatory atrophy, but it’s about time you did if you are of the male persuasion. It is similar to high-grade PIN (prostatic intraepithelial neoplasia) in that both conditions involve abnormalities of the prostate that can eventually develop into prostate cancer. More specifically, PIA includes inflammation and atrophy (tissue degradation) that typically occurs in areas of the prostate where PIN and prostate cancer also develop.

What causes PIA?

For now, the causes of PIA are unknown, although there are several theories. PIA may be caused by an infection or exposure to toxins, which can range from food additives to pesticides, air pollutants, or other environmental substances. Any of these or other factors may trigger the epithelial tissue in the prostate to deteriorate, proliferate faster than usual, or become inflamed.

Another unknown is whether PIA can lead to PIN or whether it is a different pathway in the progression to prostate cancer. These are important questions that have yet to be addressed. Thus far, research into PIA has been sparse.

PIA and prostate cancer

A number of studies have indicated that inflammation may contribute to prostate cancer and that oxidative stress triggers the development of PIA lesions which in turn can transform into cancer. A recent retrospective study of 208 patients who had prostate-specific antigen (PSA) levels of 10 ng/mL or lower looked at biopsy results and the presence of PIA lesions. Most of the samples showed inflammation; in fact, only 5.80 percent of the men had no inflammation. In addition:

  • 4 percent of the men showed evidence of PIA
  • Nearly all (88.2%) of the PIA lesions were found in biopsy cores with chronic inflammation
  • Although the study results are not definitive evidence that PIA can cause prostate cancer, they do suggest that chronic inflammation and PIA observed on initial biopsy is associated with a greater risk of identifying prostate cancer in the future

This finding suggests a need to characterize PIA as a precancerous lesion.

In a subsequent study (2014), researchers made the following determinations:

  • That the incidence of PIA globally is 30 percent of prostate biopsies
  • The association between PIA and prostate cancer is lower than high-grade PIN lesions are to the disease
  • That the association between PIN and prostate cancer is to tumors of lower or insignificant grade

The findings of this second study indicate “there is no epidemiologic evidence to consider that the PIA is associated to a greater incidence of CaP [prostate cancer] and the genetic and epidemiological data available suggest its association to not very aggressive tumors.” Overall, it appears PIA is a condition that warrants observation but not undue concern. More research may change this perspective.


Celma A et al. Clinical significance of proliferative inflammatory atrophy in prostate biopsy. Actas Urologicas Espanolas 2014 Mar; 38(2): 122-26

Stimac G. Proliferative inflammatory atrophy (PIA): new precursor lesions for prostate cancer. 2nd Croatian Congress on Urogenital and Sexually Transmitted Infections with International Participation. 2010 June