Clear Cell Papillary Renal Cell Tumor: Understanding Your Pathology Report

Section Editor: Trevor Flood MD FRCPC
October 28, 2026

Clear cell papillary renal cell tumor is a slow-growing kidney tumor made of cells with clear, pale cytoplasm arranged in small finger-like and cystic structures. It was previously called clear cell papillary renal cell carcinoma. In 2022, the World Health Organization renamed it a “tumor” because it rarely comes back or spreads after removal. Most of these tumors are small and confined to the kidney when they are found.

This article explains what a clear cell papillary renal cell tumor is, why its name changed, and how a pathologist distinguishes it from clear cell renal cell carcinoma. It also explains the grade, size, stage, and margin information in your pathology report, and what usually happens next.

Who gets clear cell papillary renal cell tumor?

Clear cell papillary renal cell tumor makes up about 1 to 4 out of every 100 kidney tumors removed by surgery. That makes it one of the more common types of kidney tumor after clear cell, papillary, and chromophobe renal cell carcinoma. It affects men and women about equally. The average age at diagnosis is about 60, but it has been reported in adults aged 18 to 88.

What causes clear cell papillary renal cell tumor?

The cause of clear cell papillary renal cell tumor is not known. The tumor was first described in people with long-standing kidney failure, especially those whose kidneys had developed many small cysts while on dialysis. Most tumors found since then have occurred in people with otherwise normal kidneys. Unlike clear cell renal cell carcinoma, this tumor does not carry changes in the VHL gene. No other consistent genetic changes have been found.

What are the symptoms of clear cell papillary renal cell tumor?

Most clear cell papillary renal cell tumors are small and cause no symptoms. Doctors usually find them by chance on an ultrasound, CT scan, or MRI done for another reason. A larger tumor may rarely cause blood in the urine or pain in the side or back.

How is the diagnosis made?

Clear cell papillary renal cell tumor is usually first seen on imaging as a kidney mass. A pathologist diagnoses it by examining tissue from the tumor under a microscope. The tissue may come from a needle biopsy. More often, it comes from surgery to remove part of the kidney (a partial nephrectomy) or the whole kidney (a radical nephrectomy).

Under the microscope, the tumor is usually well defined and surrounded by a thin capsule. The tumor cells have clear cytoplasm and line small tubes, cysts, and papillae (finger-like projections). A distinctive feature is that the nuclei line up in a row toward the inner surface, away from the base. The nuclei are small and regular, which pathologists describe as low grade. Bands of muscle-like supporting tissue, or stroma, often run through the tumor. Because clear cell renal cell carcinoma can look similar, pathologists usually use special stains to confirm the diagnosis, as described in the next section.

Immunohistochemistry

Immunohistochemistry uses antibodies to show which proteins cells make. In clear cell papillary renal cell tumor, pathologists use immunohistochemistry mainly to tell it apart from clear cell renal cell carcinoma and papillary renal cell carcinoma. The stains used vary between laboratories, but typical results include:

CK7. Positive, usually with strong staining throughout the whole tumor. Clear cell renal cell carcinoma is usually negative or only patchy.
Carbonic anhydrase IX (CA9 or CA IX). Positive along the sides and base of each cell but not the inner surface. Pathologists call this a “cup-like” pattern. Clear cell renal cell carcinoma usually stains all the way around the cell.
CD10. Usually negative in this tumor, while clear cell renal cell carcinoma is usually positive.
AMACR. Negative in this tumor, while papillary renal cell carcinoma is usually positive.
GATA3. Positive in most of these tumors. Clear cell renal cell carcinoma is rarely positive for GATA3.
PAX8. Positive, which confirms that the tumor started in the kidney.

Not every tumor needs all of these stains. The pathologist interprets the results together with how the tumor looks under the microscope.

Why the name changed from carcinoma to tumor

Clear cell papillary renal cell tumor was listed as a type of carcinoma, or cancer, in the 2016 World Health Organization (WHO) classification of kidney tumors. Long-term follow-up studies later showed that it rarely recurs or spreads. In the 2022 WHO classification (5th edition), its name was changed to clear cell papillary renal cell tumor to reflect this behavior. If your report was written before 2022, or by a laboratory still using the older term, it may say clear cell papillary renal cell carcinoma. Both names describe the same tumor.

Histologic grade

Kidney tumors are usually given a WHO/ISUP grade from 1 to 4, based on how abnormal the nuclei look. Older reports may use the similar Fuhrman grade. Clear cell papillary renal cell tumor is low grade, usually grade 1 or 2. The College of American Pathologists (CAP) kidney protocol, version 4.2.0.0 (2024), lists it among tumors where low-grade features are part of the definition. A high-grade area would lead the pathologist to consider a different diagnosis. Your report may give the grade, or it may state that grading is not applicable.

Tumor size and pathologic stage

Because clear cell papillary renal cell tumor behaves so favorably, the CAP kidney protocol (version 4.2.0.0) does not require a full cancer checklist. Many reports still give the tumor size and say whether the tumor is limited to the kidney. Some laboratories also assign a pathologic tumor stage (pT) using the AJCC Cancer Staging Manual, 8th edition, which is still current for kidney tumors. Most clear cell papillary renal cell tumors fall into one of these categories:

pT1a. The tumor is 4 cm or smaller and limited to the kidney. Most tumors fall into this group.
pT1b. The tumor is larger than 4 cm but no larger than 7 cm, and limited to the kidney.
pT2. The tumor is larger than 7 cm and limited to the kidney.

Higher stages describe a tumor that has grown into fat around the kidney, into a large vein, or beyond the kidney’s outer covering. Growth beyond the kidney is very unusual for this type of tumor. Lymph nodes are rarely removed, so most reports do not include a nodal stage.

Surgical margins

A margin is the cut edge of tissue removed during surgery. After a partial nephrectomy for clear cell papillary renal cell tumor, the pathologist checks whether any tumor cells reach this edge. Following the CAP kidney protocol, your report will describe the margins in one of these ways:

Negative margin. No tumor cells are seen at the cut edge, which means the tumor was completely removed. Some reports also give the distance between the tumor and the edge.
Positive margin. Tumor cells are present at the cut edge, so that some tumor may remain in the kidney. Your care team may suggest closer imaging follow-up.

What is the prognosis?

The prognosis for people with clear cell papillary renal cell tumor is excellent. In a combined follow-up of 362 people with this tumor, none had the tumor come back or spread, and none died of it. Only a single case of spread to another part of the body has been reported in the English medical literature. These tumors have not shown necrosis, lymphovascular invasion, or perineural invasion.

The main uncertainty comes from diagnosis on a small biopsy. Some clear cell renal cell carcinomas contain areas that look like clear cell papillary renal cell tumor. When the diagnosis is made on a biopsy, the final diagnosis may change after the whole tumor is examined. People with this tumor may also have a second, separate tumor in the same or the other kidney, which can be a different type.

What happens after the diagnosis?

After clear cell papillary renal cell tumor is diagnosed, the next steps depend on how the tissue was obtained, the size of the tumor, and your age and general health. If the tumor has already been removed with negative margins, you usually don’t need further treatment. Sometimes a biopsy shows this tumor while it is still in the kidney. For that situation, the American Urological Association (AUA) renal mass guideline (2021 update) describes several approaches your care team may discuss:

Active surveillance. Regular CT, MRI, or ultrasound to watch the tumor for growth, with treatment only if it grows. This is often considered for small tumors or for people with other health problems.
Partial nephrectomy. Surgery to remove the tumor and a rim of normal tissue while keeping the rest of the kidney.
Thermal ablation. A needle placed through the skin uses heat or cold to destroy the tumor. The AUA guideline lists this as an option for tumors smaller than 3 cm.
Radical nephrectomy. Surgery to remove the whole kidney. This is less often needed for this tumor, but may be considered for a large or centrally located mass.

After treatment, follow-up imaging is usually arranged for the treated kidney and the other kidney. Your doctor will also check your kidney function, especially if part of a kidney was removed or you already have kidney disease.

Questions to ask your doctor

Does my report say clear cell papillary renal cell tumor or clear cell papillary renal cell carcinoma?
Was the diagnosis made on a biopsy or on the whole tumor after surgery?
Which special stains were done, and did they rule out clear cell renal cell carcinoma?
What is the tumor size, and is it limited to the kidney?
What grade is listed on my report?
Were the margins negative?
Is there another mass in either kidney?
Is active surveillance an option for me, or would you suggest treatment?
How often will I need imaging, and for how long?
How will my kidney function be monitored?