Pancreatoblastoma of the Pancreas: Understanding Your Pathology Report

By Jason Wasserman MD PhD FRCPC
June 16, 2026

Pancreatoblastoma is a rare cancer of the pancreas. It is the most common type of pancreatic tumor in young children, usually appearing before the age of 10, with an average age of about 4 to 5 years. It can also occur in adults, although this is uncommon. The tumor is composed of cells that exhibit several types of specialization, but its most distinctive feature under the microscope is groups of cells called squamoid nests. Many pancreatoblastomas release a protein called alpha-fetoprotein (AFP) into the blood, which can help with diagnosis and treatment monitoring. Although it is a serious cancer, pancreatoblastoma often responds well to treatment, especially in children, when the tumor can be completely removed.

This article will help you understand the findings in your pathology report, what each term means, and why it matters for your care or the care of your child.

What causes pancreatoblastoma?

Most pancreatoblastomas occur on their own, without a known inherited cause. In some cases, the tumor is associated with an inherited condition. Because these conditions can run in families, genetic counseling and testing may be recommended, which can also help relatives understand their own risk. The two most important conditions to be aware of are:

Beckwith-Wiedemann syndrome — A condition present from birth that causes overgrowth of the body and an increased risk of certain childhood tumors. It is linked to changes in a region of chromosome 11.
Familial adenomatous polyposis (FAP) — An inherited condition caused by a change in the APC gene that leads to many polyps in the colon and an increased risk of several tumors.

What are the symptoms of pancreatoblastoma?

The symptoms are often vague and are usually related to the size of the tumor. The most common is a lump or swelling in the abdomen that can be felt, along with abdominal pain, a feeling of fullness, poor appetite, weight loss, nausea, or diarrhea. Because the tumor can be large by the time it is found, these symptoms may develop gradually. Many pancreatoblastomas raise alpha-fetoprotein (AFP) levels in the blood, and this is often measured at diagnosis. In children with Beckwith-Wiedemann syndrome, the tumor may be found earlier because these children are watched closely for tumors.

How common is this tumor?

Pancreatoblastoma is very rare. Pancreatic tumors of any kind are unusual in children, but among them, pancreatoblastoma is the most common. It makes up only a tiny fraction of pancreatic tumors overall and is uncommon in adults.

How is the diagnosis made?

The workup usually begins with imaging studies such as ultrasound, CT, or MRI, which show a mass in the pancreas, often large and well defined. A blood test for AFP is frequently performed because an elevated level supports the diagnosis. The diagnosis is confirmed when a pathologist examines a tissue sample under the microscope. The sample may be obtained by a needle biopsy or after the tumor is removed by surgery.

Under the microscope, pancreatoblastoma is a cellular tumor, meaning it is made up of many tumor cells packed closely together, often arranged in groups separated by bands of supporting tissue. The tumor cells can show several types of specialization at the same time, most often resembling acinar cells (the enzyme-making cells of the pancreas) and, less often, hormone-making or duct-forming cells. The feature that most clearly identifies this tumor is the presence of squamoid nests, small whorls of flat or rounded cells scattered throughout the tumor. To confirm the diagnosis, the pathologist usually performs immunohistochemistry, a test that uses specific antibodies to detect proteins in tumor cells. Pancreatoblastomas typically stain for pancreatic enzymes such as trypsin and chymotrypsin, and the squamoid nests show an abnormal staining pattern for beta-catenin, which is a helpful diagnostic clue. Once the diagnosis is confirmed, imaging is used to measure the tumor and check whether it has spread, most often to the liver or lungs.

Histologic grade

Pancreatoblastoma is not given the well, moderately, or poorly differentiated grade used for many other cancers, because a widely accepted grading system for this tumor does not exist. The diagnosis itself indicates a malignant (cancerous) tumor. The pathologist may comment on features such as the number of dividing cells, but these do not translate into a formal grade. For this reason, your report may not include a grade, and this is expected.

Perineural invasion

Perineural invasion means that tumor cells are found around or along a nerve. It is uncommon in pancreatoblastoma. When present, it may suggest a higher risk of the tumor returning after surgery and will be described in the pathology report.

Lymphovascular invasion

Lymphovascular invasion means that tumor cells are found inside blood vessels or lymphatic vessels, which can carry tumor cells to other parts of the body. It is also uncommon in pancreatoblastoma, but when present, it raises the risk of spread and is noted in the report.

Surgical margins

A margin is the edge of the tissue that is cut during surgery to remove the tumor. The pathologist examines these edges under the microscope to see whether any tumor cells reach them. Margin status is one of the most important factors in pancreatoblastoma, because completely removing the tumor gives the best chance of cure.

Negative margin — No tumor cells are seen at the cut edge. This suggests that the tumor was completely removed and that this is associated with a better outcome.
Positive margin — Tumor cells are seen right at the cut edge. This means some tumor may have been left behind, and it may lead the treatment team to consider further surgery or additional chemotherapy.

Lymph nodes

Lymph nodes are small, bean-shaped organs that are part of the immune system. When the tumor is removed, nearby lymph nodes may also be removed and examined. Your pathology report may describe the number of lymph nodes examined and the number that contain tumor. The report may also note extranodal extension, which means tumor cells have broken through the outer capsule of a lymph node into the surrounding tissue. Whether lymph nodes contain tumor is one of the factors used to describe how far the cancer has spread.

Biomarker and molecular testing

Biomarkers are measurable changes inside tumor cells, usually involving specific genes or proteins, that help the treatment team understand a tumor and, in some cancers, choose treatment. In pancreatoblastoma, the most useful molecular findings help confirm the diagnosis and suggest inherited conditions, rather than a specific drug.

The most common change involves a growth-control pathway known as the APC/beta-catenin (Wnt) pathway. When this pathway is altered, the protein beta-catenin accumulates in tumor cells, which the pathologist can detect by immunohistochemistry, especially in the squamoid nests. A change in the APC gene can be a sign of the inherited condition familial adenomatous polyposis (FAP). Many pancreatoblastomas also show loss of a region of chromosome 11, the same region implicated in Beckwith-Wiedemann syndrome. Because of these links, germline (inherited) genetic testing and counseling are often recommended for the patient and their family.

Unlike some other cancers, pancreatoblastoma does not currently have a biomarker test that points to an approved targeted drug. In certain cases, broader molecular testing using next-generation sequencing (NGS), which reads many genes at once, may be performed to look for rare changes (such as mismatch repair deficiency) that could make immunotherapy or a clinical trial an option. For more general information about these tests, visit our Biomarkers section.

Staging

Pancreatoblastoma does not have a single staging system of its own. Instead, doctors describe how far the cancer has spread using three main pieces of information: whether the tumor can be completely removed by surgery, whether nearby lymph nodes contain tumor, and whether the tumor has spread to distant organs such as the liver or lungs. In children, the extent of disease is often grouped in a way adapted from other childhood cancers:

Localized and completely removed — The tumor is confined to the pancreas and is removed entirely with negative margins.
Localized with tumor remaining — The tumor is confined to the pancreas, but some tumor is left behind at surgery.
Spread to lymph nodes — Tumor is found in nearby lymph nodes.
Spread to distant organs — Tumor is found in other organs, most often the liver or lungs.

This grouping helps guide how intensive treatment needs to be. In adults, doctors may instead use the AJCC TNM staging system, which is used for other pancreatic cancers and is based on tumor size, lymph node involvement, and distant spread.

What is the prognosis?

The outlook for pancreatoblastoma depends most on whether the tumor can be completely removed and whether it has already spread at the time of diagnosis. In children, the outlook is often favorable, and many are cured, especially when the tumor is completely removed and chemotherapy is used. The outlook is generally less favorable in adults and when the tumor has spread to distant organs at the time of diagnosis. Because many pancreatoblastomas produce AFP, the level of this protein in the blood can be monitored over time to assess treatment response and watch for cancer recurrence.

The following features are linked to a higher risk of the cancer returning or spreading:

Incomplete removal — Tumor left behind at surgery is one of the strongest predictors of the cancer returning.
Spread to distant organs — Tumor in the liver, lungs, or other organs at diagnosis indicates more advanced disease.
Spread to lymph nodes — Tumor in nearby lymph nodes indicates a higher risk.
Adult age — Pancreatoblastoma tends to behave less favorably in adults than in children.

What happens after the diagnosis?

Care for pancreatoblastoma usually involves a team that may include a surgeon, a pediatric or medical oncologist, a radiologist, a pathologist, and a genetic counselor. The findings in your pathology report help this team decide on the next steps.

Surgery to completely remove the tumor is the most important treatment and offers the best chance of cure. When the tumor is large or has spread, chemotherapy is often given first to shrink the tumor and make it easier to remove, an approach called neoadjuvant chemotherapy; the medicines used most often include cisplatin and doxorubicin. Chemotherapy may also be given after surgery. The AFP level in the blood is frequently measured during and after treatment to help track how the tumor is responding. Because pancreatoblastoma can be linked to inherited conditions such as familial adenomatous polyposis and Beckwith-Wiedemann syndrome, a referral for genetic counseling is often recommended.

After treatment, long-term follow-up is important and usually includes regular imaging and AFP blood tests to watch for the cancer returning. Children who receive chemotherapy are also followed for possible long-term effects of treatment. Supportive (palliative) care, which focuses on symptoms and quality of life, is offered alongside other treatments when needed and is a standard part of care, not only an end-of-life measure.

Questions to ask your doctor

Where in the pancreas did the tumor start, and how large was it?
Was the tumor completely removed, and were the margins negative?
Did any lymph nodes contain tumor?
Is there any evidence that the tumor spread to other organs?
Was the AFP level measured, and will it be followed over time?
Will chemotherapy be needed before or after surgery?
Could this tumor be linked to an inherited condition such as familial adenomatous polyposis or Beckwith-Wiedemann syndrome?
Should my family and I consider genetic counseling?
What follow-up tests will be needed, and for how long?
What is the chance of the tumor returning in our case?