Papillary renal cell carcinoma

by Trevor A. Flood, MD FRCPC
June 14, 2025

Papillary renal cell carcinoma is a type of kidney cancer. It develops from tiny tubes inside the kidney called tubules. It is the second most common type of kidney cancer found in adults. The outlook for papillary renal cell carcinoma can vary significantly depending on the specific type of tumour, its grade, and the extent of its spread.

What are the symptoms of papillary renal cell carcinoma?

Many people with papillary renal cell carcinoma do not experience noticeable symptoms. Often, these tumours are discovered accidentally during imaging tests done for other reasons. If symptoms do occur, they might include:

• Blood in the urine (urine may appear pink, red, or brown).

• Pain or discomfort in the side or lower back.

• A lump or swelling in the abdomen.

• Unexplained weight loss or fatigue.

• Fever without another obvious cause.

If the tumour spreads to other parts of the body (metastasis), symptoms can depend on the area involved.

What causes papillary renal cell carcinoma?

Most cases of papillary renal cell carcinoma have no known cause and occur by chance. These tumours are typically unrelated to specific exposures or health conditions. However, certain inherited genetic conditions can increase a person’s risk of developing this type of tumour.

Genetic conditions associated with papillary renal cell carcinoma

In some cases, papillary renal cell carcinoma is linked to genetic syndromes. These inherited conditions can increase the risk of developing multiple kidney tumours, often at an earlier age. If someone has multiple tumours or develops kidney cancer at a young age, doctors may recommend genetic testing to look for inherited conditions.

How is papillary renal cell carcinoma typically diagnosed?

Papillary renal cell carcinoma is often found unexpectedly during imaging tests, such as an ultrasound, CT scan, or MRI, done for other medical reasons. On these scans, the tumour usually appears as a mass or growth within the kidney.

After imaging, your doctor may recommend a biopsy, a procedure in which a small tissue sample from the tumour is removed and examined under a microscope. However, in many cases, doctors prefer to remove the entire tumour through surgery without performing a biopsy first. Surgery to remove part or all of the kidney is called a nephrectomy.

What does papillary renal cell carcinoma look like under the microscope?

Under the microscope, papillary renal cell carcinoma has tumour cells that connect together to form small, finger-like projections called papillae. These papillae extend from the surface of the tumour tissue. Pathologists use this characteristic papillary pattern to clearly identify this type of tumour.

What are the two types of papillary renal cell carcinoma?

Papillary renal cell carcinoma is divided into two groups based on the appearance of the tumour cells under a microscope:

• Type 1: Tumour cells have small, round nuclei (the part that holds the genetic material) and pale cytoplasm (cell body).

• Type 2: Tumour cells have larger, irregularly shaped nuclei and more abundant, pink cytoplasm.

Identifying the type is important because type 2 tumours are often larger, higher grade, more aggressive, and more likely to spread compared to type 1 tumours.

What is the WHO/ISUP grade, and why is it important?

Pathologists grade papillary renal cell carcinoma using the WHO/ISUP system, developed by the World Health Organization and the International Society for Urological Pathology. The grade describes how abnormal the tumour cells look under the microscope, helping predict how the tumour might behave.

The WHO/ISUP grades are:

• Grade 1: Tumour cell nuclei are small and round. Nucleoli (small structures inside the nucleus) are very difficult to see.

• Grade 2: Nuclei are slightly larger and irregularly shaped. Nucleoli are visible but only at high magnification.

• Grade 3: Nuclei are clearly enlarged, irregular, and nucleoli are easily visible, even at low magnification.

• Grade 4: Nuclei are highly irregular, very large, or bizarre. Tumours with aggressive cells, like sarcomatoid or rhabdoid cells, also belong in this category.

Higher-grade tumours (grades 3 and 4) grow faster, behave more aggressively, and are more likely to spread compared to lower-grade tumours (grades 1 and 2).

What are sarcomatoid cells, and why are they important?

Sarcomatoid cells are tumour cells that have changed their shape and behavior. Instead of being round, these cells become long and thin (spindle-shaped). Tumours containing sarcomatoid cells are considered high-grade, more aggressive, and have a higher likelihood of spreading to other parts of the body.

What are rhabdoid cells, and why are they important?

Rhabdoid cells are tumour cells that have changed their appearance to resemble muscle cells. Tumours containing rhabdoid cells are considered aggressive and are more likely to spread. The presence of rhabdoid cells also indicates a worse outlook.

What does tumour necrosis mean?

Tumour necrosis refers to areas within the tumour where cancer cells have died, typically due to the tumour’s rapid growth and inadequate blood supply. Finding tumour necrosis is important because it often indicates a more aggressive tumour and a worse prognosis.

What does tumour extension mean, and why is it important?

Tumour extension describes how far the tumour has grown beyond the kidney into nearby tissues or organs, such as surrounding fat, large blood vessels, or the adrenal gland. Tumour extension is carefully assessed and documented in your pathology report because it affects the tumour stage and prognosis. Tumours that extend outside the kidney are generally more aggressive and might need more extensive treatment.

What are surgical margins, and why are they important?

A surgical margin is the healthy tissue surrounding the tumor removed during surgery. Pathologists carefully examine these margins to see if tumor cells are present at the edges of the tissue removed.

• Negative margin: No tumor cells are present at the tissue edge. This suggests that the entire tumor was successfully removed, lowering the chance it will return.

• Positive margin: Tumor cells are found at the tissue edge. This means there might be cancer cells left in the body, which could require additional surgery or treatment.

In a partial nephrectomy (where only part of the kidney is removed), margins include the kidney tissue and surrounding fat at the area of removal. In a radical nephrectomy (the entire kidney removed), margins usually include the surrounding fat, the ureter (tube connecting the kidney to the bladder), and nearby blood vessels. Your pathology report will explain margin status clearly.

What is lymphovascular invasion, and why is it important?

Lymphovascular invasion means that tumor cells have entered small blood or lymph vessels. Blood vessels carry blood throughout the body, and lymph vessels carry a fluid called lymph, connecting to lymph nodes. If tumor cells enter these vessels, the cancer can spread to other parts of the body. The presence of lymphovascular invasion is an important finding that may influence your treatment and monitoring.

Were lymph nodes examined, and what do the results mean?

Lymph nodes are small immune organs throughout your body that help fight infection. Tumor cells sometimes spread to lymph nodes through lymph vessels. During surgery, nearby lymph nodes may be removed and examined to check for cancer spread.

• Negative lymph nodes: No tumor cells found.

• Positive lymph nodes: Tumor cells found. The presence of cancer cells in lymph nodes indicates a higher chance of cancer spreading further, possibly requiring additional treatments such as chemotherapy or immunotherapy.

Your pathology report will clearly state how many lymph nodes were examined, their location, and whether any contained cancer cells.

Pathologic staging (TNM system) for papillary renal cell carcinoma

Your doctor uses the TNM staging system to describe the severity of your tumor. This system helps your healthcare team understand how advanced the tumor is by looking at three important factors. These factors include the size of the tumor and how far it has grown (T), whether cancer cells have spread to nearby lymph nodes (N), and whether the cancer has spread to distant parts of the body (M). Knowing the TNM stage helps your doctor plan the best treatment and estimate your prognosis (outlook).

Tumour stage (T)

• T1: Tumour is 7 cm or smaller, fully within the kidney.

• T2: Tumour is larger than 7 cm, still completely within the kidney.

• T3: Tumour has grown into surrounding fat or a large vein attached to the kidney.

• T4: Tumour has grown outside the kidney and into nearby structures or organs, such as the adrenal gland.

Nodal stage (N)

• N0: No tumour cells in lymph nodes.

• N1: Tumour cells found in lymph nodes.

• NX: Lymph nodes were not examined.

Metastatic stage (M)

• M0: No evidence the tumour has spread to distant body parts.

• M1: Tumour cells have spread to distant body parts.

• MX: Metastatic spread cannot be assessed.

Higher stages mean the tumour is more advanced and may require additional treatments.

Examination of the healthy kidney tissue (non-tumour kidney)

Your pathologist will also examine the healthy kidney tissue removed during surgery. They look carefully for signs of other conditions like high blood pressure-related changes or damage caused by diabetes. Your pathology report will mention any significant findings in the non-tumour kidney tissue.

Questions to ask your doctor

• What type, grade, and stage is my tumour, and what does this mean for my treatment?

• Did my tumour have sarcomatoid or rhabdoid cells?

• Were the surgical margins negative or positive, and do I need further treatment?

• Were lymph nodes examined, and did they contain tumour cells?

• Will I need additional treatments like chemotherapy or immunotherapy?

• How often will I need follow-up visits or imaging tests?

• What lifestyle changes can help improve my prognosis?

• Should my family members consider genetic testing?