Intraductal Carcinoma of the Prostate Gland: Understanding Your Pathology Report

Section Editor: Trevor Flood MD FRCPC
October 25, 2026

Intraductal carcinoma of the prostate gland is a type of prostate cancer in which cancer cells fill and expand the existing ducts and glands of the prostate. The cancer cells grow inside these structures, which still have their normal outer layer of cells, called basal cells. Intraductal carcinoma is almost always found together with invasive prostate cancer, and it usually spreads into the ducts from that invasive cancer. Its presence is linked with a faster-growing cancer and a less favorable outlook.

This article explains what intraductal carcinoma of the prostate is, how it is diagnosed, and how it affects the grade of a prostate cancer. It also explains what intraductal carcinoma means for genetic testing, prognosis, and the next steps in your care.

Who gets intraductal carcinoma of the prostate?

Intraductal carcinoma of the prostate affects the same group of men as other prostate cancers, usually men over 60. It is uncommon in low-risk prostate cancer and much more common in higher-risk and advanced cancer. In a large review, intraductal carcinoma was found in about 2 in 100 low-risk cancers, 23 in 100 intermediate-risk cancers, and 37 in 100 high-risk cancers. It was found in more than half of metastatic or recurrent cancers.

What causes intraductal carcinoma of the prostate?

In most men, intraductal carcinoma of the prostate develops when cells from a high-grade invasive prostate cancer grow back into the existing ducts and glands. The cancer cells then spread along the inside of these ducts. Intraductal carcinoma is especially common in men who have an inherited change in a DNA repair gene called BRCA2. Studies have found intraductal carcinoma in more than 4 in 10 men with an inherited BRCA2 change. For this reason, your care team may discuss genetic testing after finding intraductal carcinoma.

What are the symptoms of intraductal carcinoma of the prostate?

Intraductal carcinoma of the prostate does not cause symptoms of its own. Men with intraductal carcinoma usually have the same symptoms as other men with prostate cancer, or no symptoms at all. Most prostate cancers are found because of a raised prostate-specific antigen (PSA) blood test or an abnormal rectal examination.

How is the diagnosis made?

The diagnosis of intraductal carcinoma of the prostate is usually made on a needle biopsy of the prostate. It may also be found after the whole prostate is removed in an operation called a radical prostatectomy. A pathologist examines the tissue under the microscope.

In intraductal carcinoma, the pathologist sees ducts and glands larger than normal, filled with cancer cells. The cancer cells may form solid sheets or dense cribriform (sieve-like) patterns. They often have large, very abnormal nuclei, and the center of the gland may contain dead cancer cells, called comedonecrosis. The pathologist also looks for an outer layer of basal cells around the filled glands. Special stains often confirm that this layer is present, as described in the next section.

Immunohistochemistry

Immunohistochemistry uses antibodies to show which proteins cells make. In intraductal carcinoma of the prostate, pathologists use immunohistochemistry mainly to show the basal cell layer around the filled glands. This helps distinguish intraductal carcinoma from invasive cribriform cancer, which lacks basal cells. Stains you may see on your report include:

p63. This stain highlights basal cell nuclei. In intraductal carcinoma, a layer of p63-positive basal cells surrounds at least part of the filled gland.
High molecular weight keratin. Stains such as 34βE12 (also called CK903) or CK5/6 highlight basal cell cytoplasm. Like p63, they show whether the basal cell layer is present.
AMACR. This protein is usually made by prostate cancer cells. A positive result in cells filling the gland supports a cancer diagnosis.

These stains are often combined into a single test, sometimes called a PIN4 or triple stain. Not every case needs these stains, and when the diagnosis is clear under the microscope, they may not be used.

Intraductal carcinoma and similar findings

Intraductal carcinoma of the prostate can look like other changes that also fill prostate glands. Your report may use one of these terms:

Intraductal carcinoma. Cancer cells fill and expand the glands and meet specific criteria, such as solid or dense cribriform growth, very large nuclei, or comedonecrosis.
Atypical intraductal proliferation. Abnormal cells fill the glands but do not meet all the criteria for intraductal carcinoma. The report may say “atypical intraductal proliferation, suspicious for intraductal carcinoma.” This finding is not given a Gleason grade, but your team may consider further testing.
High-grade prostatic intraepithelial neoplasia (HGPIN). Abnormal cells line the glands without filling or expanding them. HGPIN is a precancerous change and is far less concerning than intraductal carcinoma.

Gleason score and Grade Group

The Gleason score and Grade Group describe how abnormal prostate cancer looks under the microscope and help predict its behavior. Pathologists have debated whether to include intraductal carcinoma when calculating the Gleason score. In 2026, a joint panel of two international pathology societies, the Genitourinary Pathology Society (GUPS) and the International Society of Urological Pathology (ISUP), issued recommendations. They are summarized below:

Intraductal carcinoma with invasive cancer. When intraductal carcinoma is found with invasive cancer, include it in the Gleason score. Cribriform intraductal carcinoma is graded as pattern 4, and solid intraductal carcinoma or intraductal carcinoma with comedonecrosis is graded as pattern 5.
Intraductal carcinoma on its own. When intraductal carcinoma is found without any invasive cancer, or separate from the invasive cancer, it is not given a Gleason score or Grade Group.

Older reports may have graded intraductal carcinoma differently because the two societies previously gave different advice; many reports state which approach they used. Your care team can tell you how intraductal carcinoma affected the Gleason score on your report.

Intraductal carcinoma on a biopsy without invasive cancer

Sometimes a prostate biopsy shows intraductal carcinoma of the prostate but no invasive cancer. This is uncommon. Intraductal carcinoma usually grows from an invasive cancer. This finding therefore strongly suggests that a high-grade invasive cancer is present somewhere the biopsy needles did not reach. In one study of men with this finding who later had a radical prostatectomy, about half had cancer that had grown outside the prostate. For this reason, intraductal carcinoma on a biopsy is treated as a serious finding even when no invasive cancer is seen.

Biomarker and molecular testing

Intraductal carcinoma of the prostate is linked with changes in genes that repair damaged DNA, especially BRCA2. Testing for these changes can identify men who may benefit from specific drugs and families who may have an inherited cancer risk.

BRCA2 and other DNA repair genes

BRCA2, BRCA1, ATM, and similar genes belong to a group called homologous recombination repair (HRR) genes. They normally help cells repair DNA breaks. Germline testing uses a blood or saliva sample to look for inherited changes. Tumor testing uses the cancer tissue and next-generation sequencing (NGS) to look for changes in the tumor. US guidelines from the National Comprehensive Cancer Network (NCCN) have recommended considering germline testing for men with intermediate-risk prostate cancer that shows intraductal or cribriform features. Your report or genetic test result may describe one of these results:

No pathogenic variant detected. No harmful change was found in the genes tested. This is the most common result.
Pathogenic or likely pathogenic variant detected. A harmful change was found. In men with metastatic castration-resistant prostate cancer, this can make them eligible for a type of drug called a PARP inhibitor. For example, olaparib was approved by the US Food and Drug Administration (FDA) in 2020 for this group after earlier hormone treatment. If the change is inherited, relatives may also be at risk, and genetic counseling is usually recommended.
Variant of uncertain significance. A change was found, but we don’t know whether it is harmful. This result is not considered positive.

Our article on BRCA1 and BRCA2 in prostate cancer explains these tests and treatments in more detail. Our Biomarkers and Genetic Testing section explains other tests that may be done.

Pathologic stage

Intraductal carcinoma of the prostate does not change the pathologic stage. After a radical prostatectomy, the stage is based on the invasive cancer, using the TNM system in the 8th edition of the AJCC Cancer Staging Manual. The stage considers whether the cancer has grown outside the prostate, into the seminal vesicles, or into the lymph nodes. Our article on prostatic acinar adenocarcinoma explains these findings in detail.

What is the prognosis?

The prognosis for men with intraductal carcinoma of the prostate depends mainly on the grade and stage of the invasive cancer found with it. However, intraductal carcinoma itself is linked with a higher chance of the cancer coming back or spreading, even when the invasive cancer looks low grade.

For example, one study looked at men whose invasive cancer was Gleason score 3+3=6 but who also had intraductal carcinoma. About 25 in 100 of these men had a rising PSA within five years of surgery, compared with about 5 in 100 expected for Gleason 6 cancer alone. Intraductal carcinoma has also been linked with a higher chance of spread after radiation therapy and with shorter survival in advanced prostate cancer. Most of these studies looked back at past patients, so the exact figures vary.

What happens after the diagnosis?

After intraductal carcinoma of the prostate is found, the next steps depend on the grade and stage of any invasive cancer, the PSA level, and the results of imaging. A team that includes a urologist, a radiation oncologist, and sometimes a medical oncologist usually plans care.

Because intraductal carcinoma is linked with less favorable behavior, current European guidelines and expert panels advise against active surveillance when intraductal carcinoma is present. The options your team may discuss include radical prostatectomy or radiation therapy, often combined with hormone therapy. When intraductal carcinoma is found on a biopsy without invasive cancer, your team may also consider a repeat biopsy, an MRI, or a second opinion from a specialist pathologist.

For prostate cancer that has spread, treatment usually includes hormone therapy combined with other drugs. Genetic testing results can open further options, such as a PARP inhibitor for a harmful BRCA2 change. Your oncologist can tell you whether you qualify for any clinical trials.

Questions to ask your doctor

Was intraductal carcinoma found together with invasive cancer, or on its own?
Was intraductal carcinoma included in my Gleason score?
What is my Gleason score and Grade Group?
Was cribriform growth or comedonecrosis found?
Were special stains used to confirm the diagnosis?
Does my report mention atypical intraductal proliferation?
If no invasive cancer was found, do I need a repeat biopsy or an MRI?
Should I have germline genetic testing, tumor testing, or both?
If a BRCA2 or other gene change is found, should my family members be tested?
Is active surveillance an option for me?
Which treatment options does my team recommend considering, and why?