Prostatic intraepithelial neoplasia

Prostatic intraepithelial neoplasia (PIN) is a microscopic lesion in the prostate which is thought to be a precursor to prostate cancer. It is often found in tissue samples or operation specimens of the prostate. PIN itself does not invade the surrounding tissue, neither does it form a tumor mass or cause any symptoms. PIN may disappear, remain unchanged, or progress to prostate cancer, often over as many as ten years. The magnitude of the risk for prostate cancer in men with PIN and the optimal follow-up stategy remain controversial.

Diagnosis

PIN is frequently found by pathologists in tissue samples from needle biopsies taken via the rectum, or in surgically removed prostate tissue. PIN can be found after transurethral surgery for benign prostatic hyperplasia (the increase in size of the prostate in middle-aged and elderly men), or after complete removal for prostate cancer (a procedure called radical prostatectomy). Blood tests for prostate specific antigen, digital rectal examination, ultrasound scanning of the prostate via the rectum, fine needle aspiration or medical imaging studies (such as magnetic resonance imaging) are "not" useful for diagnosing PIN.

Histopathology

Microscopically, PIN is a collection of irregular, atypical epithelial cells. The architecture of the glands and ducts remains normal. The epithelial cells proliferate and crowding results in a pseudo-multilayer appearance. They remain fully contained within a prostate acinus (the berry-shaped termination of a gland, where the secretion is produced) or duct. The latter can be demonstrated with special staining techniques (immunohistochemistry for cytokeratins) to identify the basal cells forming the supporting layer of the acinus. In prostate cancer, the abnormal cells spread beyond the boundaries of the acinus and form clusters without basal cells. In PIN, the basal cell layer is disrupted but present.

PIN can be subdivided into different stages, based on the level of cell atypia. PIN was formerly classified as PIN 1, 2 or 3, in order of increasing cell irregularities. Nowadays, PIN 1 is referred to as low grade PIN, and PIN 2 and PIN 3 are grouped together as high grade PIN.cite journal |author=Montironi R, Mazzucchelli R, Algaba F, Lopez-Beltran A |title=Morphological identification of the patterns of prostatic intraepithelial neoplasia and their importance |journal=J. Clin. Pathol. |volume=53 |issue=9 |pages=655–65 |year=2000 |month=September |pmid=11041054 |doi= |url=http://jcp.bmj.com/cgi/pmidlookup?view=long&pmid=11041054] Only high grade PIN has been shown to be a risk factor for prostate cancer. Because low grade PIN has no significance and does not require repeat biopsies or treatment, it is not mentioned in pathology reports. As such, PIN has become synonymous with high grade PIN.

Because it is thought to be a premalignant state, PIN is often considered the prostate equivalent of what is called carcinoma in situ (localized cancer) in other organs. However, PIN differs from carcinoma in situ in that it may remain unchanged or even spontaneously regress.

Several architectural variants of PIN have been described, and many cases have multiple patterns. The main ones are tufting, micropapillary, cribriform, and flat. Although these different appearances may cause confusion with other conditions, they have not been found to be of clinical importance. Rarer types are signet-ring-cell, small-cell-neuroendocrine, mucinous, foamy, inverted, and with squamous differentiation.

Relation to prostate cancer

There are several reasons why PIN is the most likely prostate cancer precursor.cite journal |author=Montironi R, Mazzucchelli R, Lopez-Beltran A, Cheng L, Scarpelli M |title=Mechanisms of disease: high-grade prostatic intraepithelial neoplasia and other proposed preneoplastic lesions in the prostate |journal=Nat Clin Pract Urol |volume=4 |issue=6 |pages=321–32 |year=2007 |month=June |pmid=17551536 |doi=10.1038/ncpuro0815 |url=http://dx.doi.org/10.1038/ncpuro0815] PIN is more common in men with prostate cancer. High grade PIN can be found in 85 to 100% of radical prostatectomy specimens,cite journal |author=Godoy G, Taneja SS |title=Contemporary clinical management of isolated high-grade prostatic intraepithelial neoplasia |journal=Prostate Cancer Prostatic Dis. |volume=11 |issue=1 |pages=20–31 |year=2008 |pmid=17909565 |doi=10.1038/sj.pcan.4501014 |url=http://dx.doi.org/10.1038/sj.pcan.4501014] nearby or even in connection with prostate cancer. It tends to occur in the peripheral zone of the prostate. With age, it becomes increasingly multifocal, like prostate cancer. Molecular analysis has shown that high grade PIN and prostate cancer share many genetic abnormalities.cite journal |author=Hughes C, Murphy A, Martin C, Sheils O, O'Leary J |title=Molecular pathology of prostate cancer |journal=J. Clin. Pathol. |volume=58 |issue=7 |pages=673–84 |year=2005 |month=July |pmid=15976331 |doi=10.1136/jcp.2002.003954 |url=http://jcp.bmj.com/cgi/pmidlookup?view=long&pmid=15976331] This has been confirmed in a transgenic mouse model.

The risk for men with high grade PIN of being diagnosed with prostate cancer after repeat biopsy has decreased since the introduction of biopsies at more than six locations (traditional sextant biopsies).cite journal |author=Montironi R, Mazzucchelli R, Lopez-Beltran A, Cheng L, Scarpelli M |title=Mechanisms of disease: high-grade prostatic intraepithelial neoplasia and other proposed preneoplastic lesions in the prostate |journal=Nat Clin Pract Urol |volume=4 |issue=6 |pages=321–32 |year=2007 |month=June |pmid=17551536 |doi=10.1038/ncpuro0815 |url=http://dx.doi.org/10.1038/ncpuro0815]

Treatment

PIN does not require specific therapy, but close follow-up with additional biopsies is warranted. The exact timing of repeat biopsies remains an area of controversy. Studies are ongoing to evaluate the usefulness of diet modification, supplements or hormonal therapy for high grade PIN.

References

*cite journal |author=Godoy G, Taneja SS |title=Contemporary clinical management of isolated high-grade prostatic intraepithelial neoplasia |journal=Prostate Cancer Prostatic Dis. |volume=11 |issue=1 |pages=20–31 |year=2008 |pmid=17909565 |doi=10.1038/sj.pcan.4501014 |url=http://dx.doi.org/10.1038/sj.pcan.4501014
*cite journal |author=Bostwick DG, Qian J |title=High-grade prostatic intraepithelial neoplasia |journal=Mod. Pathol. |volume=17 |issue=3 |pages=360–79 |year=2004 |month=March |pmid=14739906 |doi=10.1038/modpathol.3800053 |url=http://dx.doi.org/10.1038/modpathol.3800053

Footnotes


Wikimedia Foundation. 2010.

Look at other dictionaries:

  • prostatic intraepithelial neoplasia — n the formation of neoplastic epithelial cells in the prostate gland that are believed to be early precursors of adenocarcinoma abbr. PIN * * * neoplastic changes in epithelial cells of prostatic ducts and acini showing some morphologic features… …   Medical dictionary

  • prostatic intraepithelial neoplasia — (PIN) abnormal cells in the prostate that are not cancer, but are associated with cancer within the prostate. Typically, PIN will be found in prostate biopsies taken because levels of prostate specific antigen are elevated and normally leads to… …   Medical dictionary

  • prostatic intraepithelial neoplasia — PIN abnormal cells in the prostate that are not cancer, but are associated with cancer within the prostate. Typically, PIN will be found in prostate biopsies taken because levels of prostate specific antigen are elevated, and its presence… …   The new mediacal dictionary

  • prostatic intraepithelial neoplasia — PIN. Noncancerous growth of the cells lining the internal and external surfaces of the prostate gland. Having high grade PIN may increase the risk of developing prostate cancer. Also called PIN …   English dictionary of cancer terms

  • High-grade prostatic intraepithelial neoplasia — In urologic pathology, high grade prostatic intraepithelial neoplasia, abbreviated HGPIN, is an abnormality of prostatic glands and believed to precede the development of prostate adenocarcinoma (the most common form of prostate cancer). [cite… …   Wikipedia

  • Prostatic acid phosphatase — (PAP), also prostatic specific acid phosphatase (PSAP), is an enzyme produced by the prostate. It may be found in increased amounts in men who have prostate cancer or other diseases.The highest levels of acid phosphatase are found in metastasized …   Wikipedia

  • neoplasia — The pathologic process that results in the formation and growth of a neoplasm. [neo + G. plasis, a molding] cervical intraepithelial n. dysplastic changes beginning at the squamocolumnar junction in the …   Medical dictionary

  • neoplasia — n. a form of abnormal growth that is independent of the body s normal homeostatic growth regulating mechanisms, continues after the initiating stimulus has been removed, and is purposeless. Neoplasia is always pathological. Derivatives:… …   The new mediacal dictionary

  • PIN — Prostatic intraepithelial neoplasia. Noncancerous growth of cells lining the internal and external surfaces of the prostate gland. Having high grade PIN may increase the risk of developing prostate cancer. Also called prostatic intraepithelial… …   English dictionary of cancer terms

  • List of oncology-related terms — This is a list of terms related to oncology. The original source for this list was the U.S. National Cancer Institute s public domain Dictionary of Cancer Terms . NOTOC 1 * 10 propargyl 10 deazaaminopterin * 12 O tetradecanoylphorbol 13 acetate * …   Wikipedia


Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.