Solid Pseudopapillary Neoplasm of the Pancreas: Understanding Your Pathology Report

By Jason Wasserman MD PhD FRCPC
June 16, 2026

A solid pseudopapillary neoplasm is a rare, slow-growing cancer of the pancreas. It most often affects adolescent girls and young women, although it can occur at any age and, less commonly, in men. It has a slight tendency to arise in the tail (the end) of the pancreas. Although it is a cancer, this tumor usually grows slowly and responds very well to surgery, and most people do very well after treatment, especially when the tumor is completely removed. This tumor has also been called a solid-pseudopapillary tumor or Frantz tumor.

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

What causes a solid pseudopapillary neoplasm?

The exact cause is not fully understood. The strong tendency to occur in young women suggests that hormonal factors may play a role, although the tumor itself does not cause hormone-related symptoms. Almost all solid pseudopapillary neoplasms carry an acquired change in the CTNNB1 gene. A genetic change, or mutation, is an alteration in DNA, the instruction manual inside cells. This particular change affects a protein called beta-catenin, which normally helps cells stick together and helps control growth signals. In this tumor, abnormal beta-catenin accumulates in the cell nucleus and activates growth-related genes. Even so, most of these tumors grow slowly, which helps explain their generally favorable behavior. This change is acquired during life and is not inherited, so it is not passed on to children.

What are the symptoms of a solid pseudopapillary neoplasm?

Many people have no symptoms, and the tumor is often found by chance during imaging done for another reason. When symptoms do occur, they are usually related to tumor size and may include abdominal discomfort, pain, or a feeling of fullness. Because these tumors can be large, an injury to the abdomen may cause bleeding within the tumor, leading to sudden pain. These tumors do not produce hormones, and routine blood tumor markers are usually normal.

How common is this tumor?

Solid pseudopapillary neoplasms are rare, making up less than 3 percent of pancreatic tumors overall. However, they account for a relatively large share of pancreatic tumors in people under 40 years of age. There is no known ethnic predilection.

How is the diagnosis made?

The diagnosis is made by combining imaging studies with examination of the tumor tissue under the microscope. Ultrasound, CT, or MRI typically shows a well-defined mass with both solid and cystic (fluid-filled) areas, and calcifications may be present. These imaging features often suggest the diagnosis before surgery. A definitive diagnosis is made when a pathologist examines the tumor under the microscope, usually after it has been removed.

Under the microscope, solid pseudopapillary neoplasms have a distinctive appearance. Unlike normal pancreatic tissue, the tumor cells do not resemble normal pancreatic cells, and they do not stick tightly to one another, a feature called poor cohesion. The tumor typically consists of solid areas along with structures called pseudopapillae, which form when tumor cells detach from delicate blood vessel cores, leaving behind finger-like projections. This combination of solid growth and pseudopapillary structures is characteristic and gives the tumor its name. Other common features that help confirm the diagnosis include areas of bleeding, cyst-like spaces, cholesterol crystals, foamy immune cells, and calcifications. The tumor cells often contain small pink globules in their cytoplasm, and their nuclei are usually uniform and round or oval, frequently with grooves or indentations. Dividing cells (mitotic figures) are generally uncommon. Most tumors are well defined, with clear borders separating them from the surrounding pancreas, although small areas where the tumor extends into nearby pancreatic tissue may be seen.

To confirm the diagnosis, the pathologist usually performs immunohistochemistry, a test that uses specific antibodies to detect proteins in tumor cells. Solid pseudopapillary neoplasms show an abnormal pattern of beta-catenin staining in the nucleus and cytoplasm, which is a key diagnostic feature, and the cells often also stain for cyclin D1, vimentin, progesterone receptor, CD10, and alpha-1-antitrypsin. They are usually negative for chromogranin A and for pancreatic enzyme markers such as trypsin, which helps separate them from pancreatic neuroendocrine tumors and acinar cell carcinoma. Molecular testing is usually unnecessary, but when performed, almost all tumors show a change in exon 3 of the CTNNB1 gene, which supports the diagnosis.

Histologic grade

Solid pseudopapillary neoplasms are not given the well, moderately, or poorly differentiated grade used for many other cancers. By their nature, they are considered low-grade tumors, which means they usually grow slowly and are unlikely to spread. For this reason, your report may not include a grade, and this is expected.

In rare cases, part of the tumor changes into a faster-growing, more abnormal form, a process called high-grade transformation. When this happens, the affected areas show sheets of more abnormal-looking cells with larger, darker nuclei and more dividing cells, and the usual pseudopapillary pattern is often lost. High-grade transformation is thought to occur when additional genetic changes build up over time. Tumors with high-grade transformation are more likely to spread and carry a less favorable outlook, so this finding, when present, is described in the report.

Perineural invasion

Perineural invasion means that tumor cells are found around or along a nerve. Nerves act like small pathways through tissues, and some cancers can use them to spread locally. In solid pseudopapillary neoplasms, perineural invasion is uncommon. When present, it may suggest that the tumor is behaving more actively, but on its own, it does not necessarily mean the cancer will spread to distant organs.

Lymphovascular invasion

Lymphovascular invasion means that tumor cells are found inside small blood vessels or lymphatic channels, which can provide a route for the tumor to spread. Lymphovascular invasion is rare in solid pseudopapillary neoplasms. If it is identified, it indicates a higher risk of spread than in tumors that do not show it, which is why its presence or absence 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.

Negative margin — No tumor cells are seen at the cut edge. This suggests the tumor was completely removed and is usually associated with an excellent outcome.
Positive margin — Tumor cells are seen right at the cut edge. This suggests that some tumor may remain, and it may lead the treatment team to consider further surgery or closer monitoring.

Depending on the operation, the report may name specific margins, such as the pancreatic margin (where the pancreas was cut) and, when nearby organs are removed, the cut edges of those organs.

Lymph nodes

Lymph nodes are small, bean-shaped organs that are part of the immune system. Solid pseudopapillary neoplasms rarely spread to lymph nodes, so nodes are usually removed only when they look enlarged or suspicious. If lymph nodes are examined, your report will describe how many were looked at and how many, if any, contained 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. The number of involved lymph nodes is used to assign the nodal stage (pN), described below.

Pathologic stage (pTNM)

The pathologic stage describes how far the tumor has grown and spread, based on the tissue removed during surgery. It uses the TNM system (8th edition of the American Joint Committee on Cancer, or AJCC), which combines the size and extension of the tumor (pT), the involvement of lymph nodes (pN), and spread to distant organs (pM). The M part is usually determined by imaging rather than by the pathologist. Most solid pseudopapillary neoplasms are found at an early stage.

Tumor stage (pT)

pT1 — The tumor is 2 cm or smaller.
pT2 — The tumor is larger than 2 cm but not larger than 4 cm.
pT3 — The tumor is larger than 4 cm.
pT4 — The tumor has grown into nearby major blood vessels.

Nodal stage (pN)

pNX — The lymph nodes could not be assessed, or no lymph nodes were submitted.
pN0 — No tumor was found in any lymph nodes examined.
pN1 — Tumor was found in one to three regional lymph nodes.
pN2 — Tumor was found in four or more regional lymph nodes.

What is the prognosis?

The outlook is generally excellent, especially when the tumor is completely removed. Long-term, disease-free survival is common, with more than 95 percent of patients alive five years after surgery. Many people do well even when the tumor is large or when there is limited spread to another organ, such as the liver, because these deposits can often be removed surgically. A small number of patients develop more serious disease, usually when the tumor shows high-grade transformation.

The following features are linked to a higher risk of spread or recurrence:

High-grade transformation — The most important feature linked to a worse outcome.
Spread beyond the pancreas — Tumor found in other organs or lymph nodes indicates more advanced disease.
Incomplete removal — Tumor cells left at the surgical margin raise the risk of the tumor returning.
Perineural or lymphovascular invasion — Tumor growing along nerves or inside vessels is linked to a higher risk of spread.

Because late recurrence is possible, long-term follow-up is recommended for everyone, even after complete removal.

What happens after the diagnosis?

Surgery is the main treatment and is usually curative. The type of operation depends on the location of the tumor: a tumor in the tail is usually removed with a distal pancreatectomy, a tumor near the head of the pancreas may require a Whipple procedure, and small tumors are sometimes removed on their own (enucleation). The goal is complete removal with negative margins. Even when there is limited spread to another organ such as the liver, surgery to remove those deposits can still lead to long-term survival.

Chemotherapy and radiation therapy are generally not effective for this tumor and are not part of routine care; they are considered only in the rare situations where the tumor cannot be removed or has undergone high-grade transformation. Because the tumor can return years later, long-term follow-up with imaging is recommended for all patients. Care often involves a team that may include a surgeon, a medical oncologist, a radiologist, and a pathologist. When the disease is advanced, supportive (palliative) care focuses on symptoms and quality of life and is offered alongside other treatments.

Questions to ask your doctor

What was the size of my tumor, and what is the pathologic stage (pT and pN)?
Was my tumor completely removed, and were the margins negative?
Did the tumor show any high-grade transformation?
Was there perineural or lymphovascular invasion?
Were any lymph nodes examined, and did any contain tumor?
Is there any evidence that the tumor spread outside the pancreas?
Will I need any treatment beyond surgery?
What follow-up imaging will I need, and for how long?
What is the chance of the tumor returning in my case?
Does this tumor have any implications for my family?