Chromophobe Renal Cell Carcinoma: Understanding Your Pathology Report

Section Editor: Trevor Flood MD FRCPC
July 16, 2026

Chromophobe renal cell carcinoma is a type of kidney cancer. It starts from the cells that line the tiny tubes inside the kidney called tubules, specifically the part of the tubule that fine-tunes the salt and acid balance of the urine. It is the third most common type of kidney cancer in adults, making up about 5 out of every 100 kidney cancers. The name comes from the way the cells behave with the dyes used to stain tissue in the laboratory: chromophobe means “color-fearing,” because the cells take up very little of the usual pink dye and look pale.

Of the common types of kidney cancer, chromophobe renal cell carcinoma has the best outlook. Most are cured by surgery alone, and spread to other parts of the body is uncommon. Your pathology report describes the features that identify the small number of tumors that behave differently, in particular unusual cell types called sarcomatoid or rhabdoid cells.

This article will help you understand the findings in your pathology report for chromophobe renal cell carcinoma, what each term means, and why it matters for your care. If you are looking for a grade on your report and cannot find one, the section below on grading explains why.

What causes chromophobe renal cell carcinoma?

Most chromophobe renal cell carcinomas, the third most common type of kidney cancer, happen by chance, and there is usually no event or exposure that explains why the tumor developed. Within tumor cells, the typical change is unusual: instead of a single damaged gene, these tumors lose entire chromosomes, most often chromosomes 1, 2, 6, 10, 13, 17, and 21. A normal cell carries two copies of each chromosome, and these tumors are left with only one copy of several of them. This pattern of multiple whole-chromosome losses is sufficiently characteristic to help confirm the diagnosis. Chromophobe renal cell carcinoma also carries fewer gene mutations than almost any other cancer, a point that becomes relevant in the section on biomarker testing below.

The risk factors that are firmly linked to kidney cancer overall, including smoking, obesity, and high blood pressure, are more clearly associated with clear cell renal cell carcinoma than with this type. No strong environmental cause has been established for chromophobe renal cell carcinoma.

Inherited conditions associated with chromophobe renal cell carcinoma

Birt-Hogg-Dubé syndrome is the inherited condition most closely linked to this tumor. It is caused by a change in a gene called FLCN that a person is born with, and it is passed from parent to child. People with Birt-Hogg-Dubé syndrome often develop several kidney tumors, in one or both kidneys, and typically at a younger age than usual. The kidney tumors are most often chromophobe renal cell carcinoma, oncocytoma, or tumors that show features of both, which pathologists call hybrid oncocytic tumors. Two findings outside the kidney point toward the syndrome: small bumps on the skin of the face and neck (fibrofolliculomas), and cysts in the lungs, which can cause a lung to collapse.

Because chromophobe renal cell carcinoma is uncommon and its link to Birt-Hogg-Dubé syndrome is strong, the possibility of an inherited condition is raised more often here than for other kidney cancers, particularly when a person is young, has more than one tumor, or has a family history of kidney tumors, collapsed lung, or the skin findings described above.

What are the symptoms of chromophobe renal cell carcinoma?

Most people with chromophobe renal cell carcinoma, a cancer that starts in the kidney, have no symptoms. These tumors are usually found by accident when an ultrasound, CT scan, or MRI is performed for an unrelated reason, and they can grow to a large size before causing any problem. When symptoms do occur, they may include:

Blood in the urine can make it look red, pink, or brown.
Pain or a dull ache in the back or the side of the abdomen.
A lump or fullness in the abdomen or side.
Weight loss that was not intended, or fatigue.

Many of these symptoms are caused far more often by conditions other than cancer, which is why tests are needed to make the diagnosis. If the tumor has spread to another part of the body (a process called metastasis), the symptoms depend on where it has spread; in this type of kidney cancer, the liver and bones are involved more often than the lungs.

How is the diagnosis made?

The diagnosis of chromophobe renal cell carcinoma is made when a pathologist examines kidney tissue under a microscope. The tumor is usually first seen as a mass in the kidney on an ultrasound, CT scan, or MRI. For most kidney masses, the next step is surgery to remove the tumor rather than a needle biopsy. A biopsy is more likely to be performed when the mass is small and treatment options are being weighed, when a person is not well enough for surgery, or when the cancer has already spread and a tissue diagnosis is needed before drug treatment can start. This tumor is difficult to diagnose confidently on a small needle biopsy, because the features that separate it from a noncancerous oncocytoma may not be visible in a small sample.

Under the microscope, chromophobe renal cell carcinoma is made up of large cells arranged in sheets. Several features together make the diagnosis. The cell borders are unusually thick and distinct, so the tumor is often described as resembling plant cells. Many cells have a clear ring around the nucleus called a perinuclear halo. The nuclei themselves are wrinkled and irregular, an appearance pathologists describe as raisin-like, and cells with two nuclei are common. Importantly, these irregular nuclei are a normal feature of this tumor rather than a sign that it is growing quickly, which is the reason it is not graded (explained in the next section).

Because a noncancerous oncocytoma can look very similar, a test called immunohistochemistry, which uses special stains to detect proteins inside cells, is usually performed. Chromophobe renal cell carcinoma is typically positive for CK7 in most of the tumor cells, positive for CD117, and positive for PAX8 (which confirms the tumor started in the kidney). Oncocytoma, by contrast, shows CK7 in only scattered cells. When the distinction remains difficult, testing for the pattern of whole-chromosome losses described above, using a method called fluorescence in situ hybridization (FISH) or a copy number test, can settle it. Other tumors that must be separated from chromophobe renal cell carcinoma include succinate dehydrogenase-deficient renal cell carcinoma, eosinophilic solid and cystic renal cell carcinoma, and two recently described tumors in the same family, eosinophilic vacuolated tumor and low-grade oncocytic tumor. Once the diagnosis is confirmed, imaging of the chest and abdomen is used to look for spread.

Classic and eosinophilic appearances

Chromophobe renal cell carcinoma comes in two appearances, and your report may name one of them. In the classic appearance, most of the cells are large and pale with abundant, almost transparent interiors. In the eosinophilic appearance, the cells are smaller and their interiors are packed with mitochondria, the parts of a cell that make energy, which turns them bright pink under the standard stain. Many tumors contain a mixture of both, and the diagnosis is the same either way.

This distinction is worth explaining for one reason: the eosinophilic appearance is the one that most closely resembles a noncancerous oncocytoma, and it is where the special stains described above do the most work. Naming the eosinophilic appearance on a report is a description of what the cells look like. It is not a sign that the tumor is more likely to spread, and it does not change how the tumor is staged or followed.

Why chromophobe renal cell carcinoma is not given a grade

Most cancers are given a grade, a number describing how abnormal the cells look under the microscope. Kidney cancers are graded using the WHO/ISUP grading system, which runs from grade 1 to grade 4 and is based on how easily the nucleoli inside the tumor cells can be seen. That system is not applied to chromophobe renal cell carcinoma, and your report will usually not contain a grade for this tumor. This is expected and appropriate, and it is not an oversight.

The reason lies in the biology of the tumor. WHO/ISUP grading works by measuring how abnormal the nuclei look, and it was validated for clear cell and papillary renal cell carcinoma, where that measurement predicts behavior. Chromophobe renal cell carcinoma has strikingly abnormal, wrinkled nuclei in every case, including tumors that are entirely cured by surgery. Applied here, the system would label almost every tumor high grade while telling no one anything useful, so both the World Health Organization and the College of American Pathologists advise against using it for this tumor. Grading systems designed specifically for chromophobe renal cell carcinoma have been proposed and are being studied, but none has been adopted into routine practice.

Two consequences are worth knowing. First, if you are comparing your report with information written about kidney cancer in general, the absence of a grade does not mean your tumor was not assessed. Second, because there is no grade, the other findings on the report carry the weight: the stage, the tumor size, whether sarcomatoid or rhabdoid cells are present, and whether tumor necrosis was seen. Older reports issued before this recommendation took hold may still contain a Fuhrman grade or a WHO/ISUP grade for a chromophobe tumor. Such a grade should be interpreted with caution, and a high number on an older report does not carry the same meaning it would for a clear cell tumor.

Sarcomatoid and rhabdoid features

Some chromophobe renal cell carcinomas contain areas in which the tumor cells have completely changed their appearance. These changes, called sarcomatoid and rhabdoid features, are the single most important findings in a report for this type of kidney cancer, because, in the absence of a grade, they are the clearest signal that a tumor may behave differently from the usual chromophobe renal cell carcinoma. They are uncommon, found in fewer than 1 in 10 of these tumors.

Sarcomatoid features — The tumor cells are replaced by long, thin, spindle-shaped cells that resemble a soft tissue cancer rather than a carcinoma.
Rhabdoid features — The tumor cells become large and round with a bright pink center and an off-to-the-side nucleus, resembling muscle cells.

Your report will state the percentage of the tumor involved. When sarcomatoid features are present, the risk that the cancer will return or spread is substantially higher, and outcomes in this situation are markedly worse than for chromophobe renal cell carcinoma without them. Tumors with sarcomatoid features also tend to respond better than average to immunotherapy, so this finding is one of the details the medical oncology team uses when discussing drug treatment. If your report does not mention sarcomatoid or rhabdoid cells, they were not found.

Tumor size

Your pathology report will state the size of the chromophobe renal cell carcinoma, measured in centimeters, from the tissue removed at surgery. This measurement is more accurate than the size estimated on imaging beforehand, so the two numbers may not match exactly. Size matters because it is one of the main factors that determines the tumor stage (pT). Chromophobe renal cell carcinomas are often larger at diagnosis than other kidney cancers, because they cause symptoms late and can grow for a long time without spreading. A large chromophobe tumor is therefore less concerning than a clear cell tumor of the same size, although size still counts toward the stage. The important thresholds are 4 cm, 7 cm, and 10 cm.

Tumor extension

Tumor extension describes whether a chromophobe renal cell carcinoma has grown outside the kidney and, if so, how far. The kidney is surrounded by a layer of fat, and outside that fat is a tough envelope called Gerota’s fascia. The adrenal gland sits on top of the kidney, and the renal vein carries blood away from the kidney into the largest vein in the body, the inferior vena cava. Your pathologist examines all of these structures in the tissue removed at surgery.

The report may describe growth into the fat around the kidney (perinephric fat), into the fat in the middle of the kidney where the blood vessels enter (renal sinus fat), into the collecting system that drains urine (the pelvicalyceal system), into the renal vein or the inferior vena cava, into the adrenal gland, or through Gerota’s fascia into other organs. Most chromophobe renal cell carcinomas stay within the kidney and are surrounded by a capsule. When growth outside the kidney is present, it raises the tumor stage and is associated with a higher risk of the cancer returning.

Lymphovascular invasion

Lymphovascular invasion means that cells from chromophobe renal cell carcinoma are present within small blood vessels or lymphatic channels within or around the tumor. Blood vessels carry blood throughout the body, and lymphatic channels carry a fluid called lymph toward the lymph nodes. Tumor cells inside these vessels can be carried elsewhere, so lymphovascular invasion is associated with a higher risk of the cancer returning or spreading. It is uncommon in this type of kidney cancer.

Lymphovascular invasion is not the same as growth into the renal vein, which is a large named vessel and is reported separately as part of tumor extension and stage. Lymphovascular invasion does not change the pT stage on its own, but because chromophobe renal cell carcinoma is not graded, it is one of the few microscopic findings available to the treatment team when deciding how closely to follow you after surgery.

Surgical margins

A margin is the cut edge of the tissue removed during surgery for chromophobe renal cell carcinoma. Your pathologist examines these edges under the microscope to see whether any tumor cells reach them. Which margins are examined depends on the operation. In a partial nephrectomy, where only the tumor and a rim of surrounding tissue are removed, the margins are the kidney tissue and fat around the tumor. In a radical nephrectomy, where the whole kidney is removed, the margins include the fat around the kidney, the renal vein, the ureter (the tube carrying urine to the bladder), and the blood vessels.

Negative margin — No tumor cells are seen at the cut edge. This suggests the whole tumor was removed and is associated with a low risk of the cancer coming back in the same place.
Positive margin — Tumor cells are present at the cut edge. This means tumor cells may have been left behind, and it is associated with a higher risk of the cancer returning at that site. A positive margin is one of the findings the surgical team uses when deciding whether more surgery or closer imaging follow-up should be considered.

Lymph nodes

Lymph nodes are small immune organs found throughout the body, including around the large blood vessels near the kidney. Cells from a chromophobe renal cell carcinoma can travel through lymphatic channels and settle in a lymph node, although this is uncommon. Lymph nodes are not removed routinely during kidney cancer surgery. They are usually removed only when they look enlarged on imaging or feel abnormal during the operation, so many reports for this cancer will say that no lymph nodes were submitted.

If lymph nodes were removed, your report will state how many were examined, how many contained cancer, and the size of the largest deposit of tumor within a node. It may also state whether extranodal extension is present, which means that cancer cells inside a lymph node have broken through the outer capsule of the node into the surrounding tissue. Cancer in even one lymph node is an important finding, because it is associated with a substantially higher risk of the cancer returning and it places the tumor in a higher stage group.

Examination of the non-tumor kidney

When kidney tissue is removed for chromophobe renal cell carcinoma, your pathologist also examines the kidney tissue away from the tumor. This part of the report is easy to overlook, but it describes how well the remaining kidney is likely to work after surgery. Common findings include scarring of the small blood vessels from long-standing high blood pressure (arterionephrosclerosis), damage to the filters from diabetes (diabetic nephropathy), and scarring from other chronic kidney disease. Your pathologist may also note additional small tumors, such as oncocytomas, in the surrounding kidney, which raises the possibility of Birt-Hogg-Dubé syndrome. These findings do not describe the cancer itself. They are reported because they help predict kidney function after surgery and may lead to a referral to a kidney specialist (nephrologist) or a genetics clinic.

Biomarker and molecular testing

Biomarkers are features of a tumor, usually proteins or gene changes, that provide information beyond the diagnosis itself. In some cancers, biomarker results decide which drug a person receives. Chromophobe renal cell carcinoma is not one of them: no biomarker test is required before treatment for this cancer can be chosen, and most people whose tumor is removed will not have any molecular testing performed, because surgery alone is usually curative. The tests below are performed in specific situations, most often when an inherited condition is suspected or in the small number of cases where the cancer has spread.

Inherited (germline) genetic testing

Germline testing looks for a gene change a person was born with, using a blood or saliva sample rather than the tumor itself. It comes up more often with chromophobe renal cell carcinoma than with other kidney cancers because of the strong link to Birt-Hogg-Dubé syndrome. Testing is offered to people diagnosed at a young age (usually 46 or younger), those with more than one kidney tumor or tumors in both kidneys, those with a family history of kidney tumors or collapsed lung, and those with the skin bumps or lung cysts characteristic of the syndrome. The main gene tested is FLCN, sometimes alongside other kidney cancer genes.

Results are reported in one of three ways: a pathogenic (disease-causing) variant, which confirms Birt-Hogg-Dubé syndrome; no variant identified, which is the usual and reassuring result; or a variant of uncertain significance, which means a change was found but it is not yet known whether it matters. A pathogenic result matters for the whole family. It indicates a need for lifelong imaging of the kidneys, awareness of the risk of a collapsed lung, and it means close relatives can be offered testing of their own (called cascade testing) through a genetics clinic.

Comprehensive genomic profiling (next-generation sequencing)

Next-generation sequencing reads many genes at once from the tumor tissue. In chromophobe renal cell carcinoma, it is generally performed only when the cancer has spread and a clinical trial or a treatment outside the standard options is being considered. Because these tumors carry so few mutations, panels often return little. The genes most often altered are TP53 and PTEN, both of which are tumor suppressor genes, and both are found more often in tumors that have spread or that contain sarcomatoid cells. Some tumors carry changes in the genes of the mTOR pathway, which controls cell growth; these have been linked to poorer outcomes and are of interest because drugs that block mTOR already exist, although their use here is not yet standard and remains a question for clinical trials. Reports may state which alterations were found, that no reportable alterations were identified, or that a change of uncertain significance was detected.

Mismatch repair, microsatellite instability, and tumor mutational burden

These tests identify tumors that respond to immunotherapy regardless of where the cancer started, a concept known as tumor-agnostic approval. Mismatch repair proteins (MLH1, PMS2, MSH2, and MSH6) are tested by immunohistochemistry and reported as intact or retained, which is the normal result, or as deficient (dMMR) when one or more proteins are lost. The related test for microsatellite instability is reported as stable (MSS) or high (MSI-H). Tumor mutational burden counts the number of mutations in the tumor and is reported as mutations per megabase, with 10 or more considered high. Chromophobe renal cell carcinoma has one of the lowest tumor mutational burdens of any cancer, and all three of these findings are rare in it, so a normal result is very much expected. When one of them is present, it can make a person eligible for the immunotherapy drug pembrolizumab under approvals that apply across cancer types.

You can learn more about the tests described here in our Biomarkers and Genetic Testing section.

Pathologic stage (pTNM)

The pathologic stage of a chromophobe renal cell carcinoma describes how far the cancer had grown at the time of surgery. It is written using the TNM system created by the American Joint Committee on Cancer (AJCC), currently in its 8th edition, and it is the same system used for all renal cell carcinomas. T describes the size of the tumor and how far it has grown outside the kidney, N describes whether cancer is found in nearby lymph nodes, and M describes whether the cancer has spread to a distant part of the body. The letter “p” in front means the category was assigned by a pathologist after examining the tissue. The M category is almost always determined by imaging rather than by the pathologist, so it may not appear on your report at all. Because this tumor is not graded, the stage carries more of the prognostic weight here than it does for other kidney cancers.

Tumor stage (pT)

pT1a — The tumor is 4 cm or smaller and remains inside the kidney.
pT1b — The tumor is larger than 4 cm but not more than 7 cm and remains inside the kidney.
pT2a — The tumor is larger than 7 cm but not more than 10 cm and remains inside the kidney.
pT2b — The tumor is larger than 10 cm and remains inside the kidney.
pT3a — The tumor has grown into the renal vein or one of its branches, into the fat around the kidney or in the renal sinus, or into the collecting system that drains urine, but not beyond Gerota’s fascia.
pT3b — The tumor has grown into the inferior vena cava below the diaphragm.
pT3c — The tumor has grown into the inferior vena cava above the diaphragm, or into the wall of the vena cava.
pT4 — The tumor has grown beyond Gerota’s fascia, including growth into the adrenal gland on the same side.

Nodal stage (pN)

pN0 — No cancer was found in any of the lymph nodes examined.
pN1 — Cancer was found in one or more nearby lymph nodes.
pNX — No lymph nodes were removed or they could not be assessed. This is a common and expected result in kidney cancer surgery.

What is the prognosis?

Prognosis means the expected course of a disease. Chromophobe renal cell carcinoma has the most favorable outlook of the common kidney cancers. Most are confined to the kidney when found, spread to other parts of the body occurs in fewer than 1 in 10 people, and five-year survival for tumors confined to the kidney is reported at roughly 90% or better. Stage for stage, this type does better than clear cell renal cell carcinoma. When these tumors do spread, they tend to do so later than other kidney cancers, which is one reason follow-up continues for many years.

Because this tumor is not graded, the features on your pathology report associated with a higher risk of the cancer returning are:

Sarcomatoid or rhabdoid features — By a wide margin the most important adverse finding in this type of kidney cancer. Tumors with sarcomatoid features spread far more often, and outcomes once they have spread are poor.
Tumor necrosis — Areas where tumor cells have died, usually because the tumor outgrew its blood supply. Necrosis seen under the microscope is associated with a higher risk of the cancer returning.
Growth outside the kidney — Involvement of the fat around the kidney, the renal sinus, the renal vein, or the vena cava.
Larger tumor size — Size counts toward the stage, although a large tumor confined to the kidney carries less risk in this type than the same size would in a clear cell tumor.
Lymphovascular invasion — Tumor cells within small blood or lymphatic vessels.
Positive surgical margin — Tumor cells at the cut edge of the tissue removed.
Cancer in lymph nodes — Uncommon, but associated with a considerably higher risk when present.

Urologists combine stage, tumor size, necrosis, and sarcomatoid features into published risk scores, including a version of the Leibovich score developed specifically for chromophobe renal cell carcinoma, to estimate the chance that the cancer will return after surgery. Your treatment team uses one of these scores, along with the details on your report, to decide how often you will have imaging.

What happens after the diagnosis?

Once chromophobe renal cell carcinoma has been confirmed, the findings on your pathology report, particularly the stage, the margin status, and whether sarcomatoid or rhabdoid cells were found, shape the next steps in your care. Kidney cancer is managed by a team that usually includes a urologist, a radiologist, and a pathologist, and may include a medical oncologist, a genetic counselor, and a nephrologist.

Surgery — For tumors confined to the kidney, surgery is the main treatment and is usually curative. A partial nephrectomy removes the tumor and preserves the rest of the kidney; a radical nephrectomy removes the whole kidney and is considered for larger tumors or tumors involving the renal vein. Because these tumors are often large but still confined to the kidney, the choice of operation depends on the position of the tumor as much as its size. For some small tumors, active surveillance with regular imaging, or an ablation procedure that destroys the tumor with heat or cold, may be discussed instead.
Treatment after surgery (adjuvant therapy) — No drug treatment after surgery has been shown to help in chromophobe renal cell carcinoma. The immunotherapy options approved for use after kidney cancer surgery, including pembrolizumab and the pembrolizumab and belzutifan combination approved in June 2026, were studied in and approved for renal cell carcinoma with a clear cell component, and they do not apply to this tumor. For nearly everyone, the plan after surgery is imaging surveillance rather than drug treatment.
Treatment for cancer that has spread — This situation is uncommon enough that no treatment has been tested in a trial devoted to chromophobe renal cell carcinoma alone, and options are drawn from studies of kidney cancers other than clear cell. Those the team may consider include the immunotherapy combination of ipilimumab and nivolumab, cabozantinib, and pembrolizumab combined with lenvatinib. Drugs blocking the mTOR pathway have also been used, reflecting the changes in that pathway found in some of these tumors. Because the evidence base is thin, a clinical trial is discussed more often here than for other kidney cancers. Chemotherapy is not effective and is not used. Surgery or radiation may be considered for a single site of spread.
Follow-up — Follow-up includes imaging of the abdomen and chest on a schedule set by the risk score, along with blood tests of kidney function. Because this tumor can return later than other kidney cancers, follow-up is often continued for a longer period.
Genetic assessment — A referral to a genetics clinic may be offered if you were diagnosed young, had more than one kidney tumor, have a family history of kidney tumors or collapsed lung, or have skin findings that suggest Birt-Hogg-Dubé syndrome. Confirming the syndrome changes the follow-up plan for you and allows relatives to be tested.

Questions to ask your doctor

My report does not include a grade. Is that expected for this type of kidney cancer?
How large was my tumor, and what was the pathologic stage (pT and pN)?
Did my tumor contain sarcomatoid or rhabdoid cells, and if so, what percentage?
Was tumor necrosis seen under the microscope?
Was my tumor the classic or the eosinophilic appearance, and does that change anything for me?
How was my tumor distinguished from an oncocytoma, and were special stains or chromosome testing used?
Did the tumor grow outside the kidney, into the fat, the renal sinus, or the renal vein?
Were the surgical margins negative or positive, and if positive, where?
Were any lymph nodes removed, and did any contain cancer?
Was more than one tumor found in my kidney or in the surrounding kidney tissue?
Should I be referred for genetic counseling to look for Birt-Hogg-Dubé syndrome, and should my family be tested?
What risk score was calculated for my tumor, and what is my chance of the cancer returning?
What did the report say about the non-tumor kidney, and how well is my remaining kidney working?
How often will I need imaging, and for how many years?