High-Grade Prostatic Intraepithelial Neoplasia (HGPIN): Understanding Your Pathology Report

Section Editor: Trevor Flood MD FRCPC
October 26, 2026

High-grade prostatic intraepithelial neoplasia, or HGPIN, is a change in the cells that line the ducts and glands of the prostate gland. In HGPIN, the lining cells look abnormal under the microscope, but they stay within the existing ducts and glands and do not invade the surrounding tissue. HGPIN is not cancer. It is considered a precancerous change because it shares some features with prostate cancer and is often found near it.

This article explains what high-grade prostatic intraepithelial neoplasia means, how it is diagnosed, and how it differs from other similarly named findings. It also explains what HGPIN means for your risk of prostate cancer and what follow-up your care team may recommend.

Who gets high-grade prostatic intraepithelial neoplasia?

High-grade prostatic intraepithelial neoplasia is common in older men, the same group most likely to develop prostate cancer. It is usually found on a prostate biopsy done because of a raised prostate-specific antigen (PSA) blood test or an abnormal rectal examination. HGPIN may be found on its own, or in the same biopsy as prostate cancer. When prostate cancer is also present, the cancer guides the next steps, and the HGPIN does not change them.

What causes high-grade prostatic intraepithelial neoplasia?

The cause of high-grade prostatic intraepithelial neoplasia is not fully understood. HGPIN develops when the cells lining the prostate ducts and glands acquire some of the genetic changes also seen in prostate cancer. These changes allow the cells to grow more than normal and to look abnormal. However, the cells cannot yet break out of the glands and invade the surrounding tissue.

What are the symptoms of high-grade prostatic intraepithelial neoplasia?

High-grade prostatic intraepithelial neoplasia does not cause any symptoms. HGPIN is found only when prostate tissue is examined under the microscope, usually on a biopsy done for another reason.

How is the diagnosis made?

High-grade prostatic intraepithelial neoplasia is diagnosed on a needle biopsy of the prostate, in which several thin cores of tissue are removed. It may also be found in tissue removed by surgery for another reason, such as an enlarged prostate. A pathologist examines the tissue under the microscope.

In HGPIN, the ducts and glands are normal in size and shape, but the cells lining them look abnormal. The cells are crowded and have enlarged, dark nuclei, which are the parts of the cell that hold its genetic material. Many of the nuclei contain large, easily seen nucleoli. The glands keep their normal outer layer of basal cells. This outer layer shows that the abnormal cells have not invaded the tissue around the gland.

Your report may also say how many biopsy cores contain HGPIN. This number matters for your risk of prostate cancer, as explained below.

Immunohistochemistry

Immunohistochemistry uses antibodies to show which proteins cells make. When the diagnosis of high-grade prostatic intraepithelial neoplasia is uncertain, pathologists use immunohistochemistry to look for the basal cell layer around the abnormal glands. Stains you may see on your report include:

p63 and high molecular weight keratin. These stains highlight basal cells. In HGPIN, at least some basal cells are present around the abnormal glands. In invasive prostate cancer, basal cells are absent.
AMACR. This protein is often made by both HGPIN and prostate cancer cells. A positive result does not, by itself, mean cancer, so it is always interpreted with the basal cell stains.

These stains are often combined into a single test, sometimes called a PIN4 or triple stain. Not every biopsy with HGPIN needs these stains.

Number of cores involved

When a biopsy shows high-grade prostatic intraepithelial neoplasia, your report may describe how many cores contain it. Your report may use one of these terms:

Unifocal or focal HGPIN. HGPIN is found in only one biopsy core. This is the more common finding, and it carries about the same cancer risk as a benign biopsy.
Multifocal HGPIN. HGPIN is found in two or more biopsy cores. This finding is linked with a higher chance that prostate cancer will be found on a later biopsy.

HGPIN and similar findings

Several findings in a prostate biopsy have names or appearances similar to high-grade prostatic intraepithelial neoplasia, but they mean different things. Your report may use one of these terms:

Low-grade PIN. Pathologists no longer report this milder change because it does not change cancer risk and they cannot reliably agree on it.
HGPIN with adjacent atypical glands. HGPIN is present, and a few small nearby glands look suspicious for cancer but cannot be confirmed. This is managed like atypical small acinar proliferation (ASAP), which more often leads to further testing.
Intraductal carcinoma. Cancer cells fill and expand the ducts and glands. Unlike HGPIN, intraductal carcinoma is usually linked with a high-grade invasive cancer and is treated as a serious finding.
PIN-like carcinoma. The glands look like HGPIN but lack basal cells. This is an invasive cancer, usually with a low grade, and is described in our article on prostatic acinar adenocarcinoma.

What is the risk that HGPIN will turn into cancer?

High-grade prostatic intraepithelial neoplasia does not always lead to prostate cancer. The risk depends mainly on how many biopsy cores contain HGPIN. One large study followed men who had a second biopsy. Prostate cancer was found in about 9 in 100 men whose first biopsy showed HGPIN in a single core. Cancer was found in about 30 in 100 men whose first biopsy showed HGPIN in two or more cores. For comparison, cancer was found in about 14 in 100 men whose first biopsy was benign.

These figures mean that a single focus of HGPIN on a modern biopsy carries about the same risk as a benign biopsy. Multifocal HGPIN carries a higher risk, and many men in this group still never develop prostate cancer.

What happens after the diagnosis?

High-grade prostatic intraepithelial neoplasia is not cancer, so it does not need surgery, radiation, or other cancer treatment. Next steps depend on the number of cores involved, PSA level, rectal examination, and imaging. The American Urological Association and the Society of Urologic Oncology (AUA/SUO) updated their recommendations in 2026:

HGPIN in one core. An immediate repeat biopsy is not recommended. Your care team usually continues routine PSA testing and follow-up.
HGPIN in two or more cores. Your care team may recommend further evaluation based on your PSA level, rectal examination, and prostate MRI. A repeat biopsy may be considered depending on these results.
HGPIN with adjacent atypical glands. Further testing, which may include a repeat biopsy, is usually recommended.

If a repeat biopsy is planned, an MRI of the prostate is usually done first. The MRI can show suspicious areas so that the biopsy needles can be aimed there. Your doctor can explain which follow-up plan fits your situation.

Questions to ask your doctor

How many biopsy cores contained HGPIN?
Was any cancer or atypical small acinar proliferation found in my biopsy?
Did my report mention atypical glands next to the HGPIN?
Were special stains used, and what did they show?
Does HGPIN change my risk of prostate cancer?
Do I need a repeat biopsy, and if so, when?
Should I have an MRI of the prostate?
How often should I get my PSA checked?
What changes in my PSA or symptoms should prompt further testing?