Oncocytic Adrenal Cortical Carcinoma: Understanding Your Pathology Report

Section Editor: Jason Wasserman MD PhD FRCPC
October 7, 2026

Oncocytic adrenal cortical carcinoma is a rare cancer that starts in the adrenal cortex, the outer layer of the adrenal gland. It is a subtype of adrenal cortical carcinoma. Your report may use the name oncocytic adrenocortical carcinoma, which means the same thing.

The word oncocytic describes how the tumor cells look under the microscope. They are large and bright pink because they are packed with mitochondria, the parts of a cell that make energy. A tumor is called oncocytic when more than 90% of its cells look this way.

As a group, oncocytic adrenal cortical carcinomas tend to grow more slowly than the usual type of adrenal cortical carcinoma. They can still come back or spread, so your report findings matter.

This article explains how oncocytic adrenal cortical carcinoma is diagnosed and what the findings in your pathology report mean. It also notes which findings appear in every report and which are optional.

How is it different from other oncocytic adrenal tumors?

Not every oncocytic tumor of the adrenal gland is a cancer. Pathologists sort these tumors into three groups, and the names are easy to confuse:

Oncocytoma. This is a noncancerous tumor. It does not spread, and removing it is usually the only treatment needed. Some reports call it an oncocytic adrenal cortical adenoma.
Oncocytic tumor of uncertain malignant potential. This tumor has one or more worrying features, but not enough to call it a cancer. Our article on uncertain malignant potential explains the term. Most behave like noncancerous tumors. Because only a small number recur, doctors usually recommend follow-up scans.
Oncocytic adrenal cortical carcinoma. This is a cancer. It has at least one feature that shows it can spread.

The group matters because each one has a different outlook and a different follow-up plan.

Who gets oncocytic adrenal cortical carcinoma?

Oncocytic adrenal cortical carcinoma most often affects adults in their 40s and 50s, although it can develop at any age. It affects men and women about equally.

What causes oncocytic adrenal cortical carcinoma?

In most people, the cause of oncocytic adrenal cortical carcinoma is not known. A small number of adrenal cortical carcinomas develop in people born with a condition that raises the risk of cancer, such as Li-Fraumeni syndrome or Lynch syndrome. For this reason, your doctor may ask about cancers in your family.

What are the symptoms?

Most oncocytic adrenal cortical carcinomas do not make extra hormones. These tumors often cause no symptoms until they are large. They can then cause abdominal or side pain, or a feeling of fullness. Some are found by accident on a scan done for another reason.

About one in three makes extra hormones. Extra cortisol is the most common and causes Cushing syndrome. Symptoms include abdominal weight gain, a rounded face, muscle weakness, easy bruising, and high blood pressure.

How is the diagnosis made?

The diagnosis of oncocytic adrenal cortical carcinoma is usually made after the tumor is removed and examined under the microscope by a pathologist. A needle biopsy is usually avoided when an adrenal cancer is suspected, because it can spread tumor cells along the needle path.

Before surgery, blood and urine tests show whether the tumor is making extra hormones. Our article on adrenal hormone tests explains these results. A CT or MRI scan shows the size of the tumor.

Under the microscope, the pathologist first confirms that the tumor is oncocytic. Next, the pathologist decides which of the three groups it belongs to. To do this, the pathologist looks for a specific set of features, described in the section on the Lin-Weiss-Bisceglia criteria below.

Once oncocytic adrenal cortical carcinoma is confirmed, scans of the chest and abdomen look for spread. The special stains sometimes used to support the diagnosis are described in the next section.

Immunohistochemistry

Immunohistochemistry uses antibodies to show which proteins tumor cells make. For oncocytic adrenal cortical carcinoma, it helps confirm that the tumor started in the adrenal cortex. This matters because oncocytic tumors from other organs, such as the kidney, can look similar.

Laboratories use different stains, and no fixed set is required. Your report may include some of the following:

SF1. A positive result supports a tumor that started in the adrenal cortex. Not every laboratory has this stain, and some oncocytic tumors are negative.
Inhibin, melan-A, and calretinin. These are often positive in adrenal cortical tumors. They are also positive in some other tumors.
Stains for look-alike tumors. Stains such as chromogranin are usually negative. A positive result would suggest a different tumor.

The stains on your report may be different from these, and some reports list very few. These stains show where the tumor started. They do not show how it will behave.

Lin-Weiss-Bisceglia criteria

The Lin-Weiss-Bisceglia criteria are the features pathologists use to decide whether an oncocytic adrenal tumor is a cancer. The usual scoring system for adrenal tumors, the Weiss score, does not work well for oncocytic tumors. Your report may name the Lin-Weiss-Bisceglia system, or it may simply list the features that were found.

The features are divided into major and minor criteria. Finding even one major criterion makes the diagnosis of oncocytic adrenal cortical carcinoma.

High mitotic count. A mitotic figure is a dividing cell. More than 5 mitotic figures in 50 high-power fields is a major criterion. It shows the tumor cells are dividing faster than a noncancerous tumor would.
Atypical mitotic figures. An atypical mitotic figure is a cell dividing abnormally. Normal cells do not divide like this, so finding even one is a major criterion.
Venous invasion. Tumor cells are seen inside a vein. This is a major criterion because it shows the tumor can enter the bloodstream.

Minor criteria are less worrying. A tumor with only minor criteria is called an oncocytic tumor of uncertain malignant potential. In a carcinoma, they may be listed alongside the major criteria.

Large size. The tumor is larger than 10 cm.
Tumor necrosis. Necrosis means areas of dead tumor cells. It happens when a tumor grows faster than its blood supply can keep up.
Capsular invasion. Tumor cells have grown into or through the capsule, the thin layer of tissue around the tumor. This is not the same as growing outside the adrenal gland, and it does not change the stage.
Sinusoidal invasion. Tumor cells are seen inside the tiny channels that run through the tumor. Some reports call this lymphatic invasion.

This system does not give a score. The number of criteria does not tell you how advanced the cancer is. The stage, grade, and Ki-67 index are better guides to the outlook.

Grade

The grade of oncocytic adrenal cortical carcinoma describes how quickly the tumor cells are dividing. The pathologist counts the mitotic figures in a set area of the tumor. This number is the mitotic count, and it should be in every report.

Low grade. There are 20 or fewer mitotic figures in 10 square millimeters. Some reports describe this area as 50 high-power fields.
High grade. More than 20 mitotic figures are present in the same area.

Most oncocytic adrenal cortical carcinomas are low grade. High-grade tumors tend to grow faster and are more likely to come back or spread. Your team uses the grade to decide on treatment after surgery.

Ki-67

Ki-67 is a protein found in cells that are getting ready to divide. The Ki-67 index is the percentage of tumor cells that contain it. It should be in every report for oncocytic adrenal cortical carcinoma. Some reports call the test MIB-1.

A higher Ki-67 index is linked to a higher chance of the cancer coming back after surgery. No cut-off is agreed on, but 10% or less is often treated as lower risk.

Other tests your report may mention

Some pathologists use additional tools to support the diagnosis of oncocytic adrenal cortical carcinoma. These are optional, and many reports do not include them.

Helsinki score. This combines the mitotic count, necrosis, and the Ki-67 index into one number. A score above 8.5 supports carcinoma. Higher scores are linked to a higher chance of the cancer spreading.
Reticulin. Reticulin is a stain that shows the fine fibers that hold groups of cells in place. In a noncancerous tumor, these fibers form a regular mesh, and the report describes them as intact. In a carcinoma, the mesh is broken up, and the report may describe it as altered or disrupted.

Tumor size and extension

Your report will give the size of the oncocytic adrenal cortical carcinoma, measured across its widest point in centimeters (cm). These tumors are often large when they are found. Your report will also describe tumor extension, which means how far the tumor has grown. Both are used to set the tumor stage.

Confined to the adrenal gland. The tumor has not grown outside the gland. This is the most favorable result and the most common for oncocytic tumors.
Invasion into extra-adrenal tissue. The tumor has grown beyond the edge of the gland into the surrounding fat. This raises the stage.
Invasion into adjacent organs. The tumor has grown directly into a nearby organ, such as the kidney or liver, or into a large vein. This is the highest tumor stage.

Margins

A margin is the edge of tissue the surgeon cuts when removing the tumor. The pathologist examines the margins to see whether any tumor cells are present at the cut edge.

Negative margin. No tumor cells are seen at the cut edge. This suggests the tumor was completely removed. Some reports call this R0.
Positive margin. Tumor cells are seen at the cut edge. This suggests some tumor may remain. Some reports call this R1.

Your report will also say whether the tumor arrived in one piece. Terms such as “capsule disrupted” or “fragmented” mean the tumor surface was opened or the tumor was in pieces. This raises the chance of the cancer coming back in the same area.

Pathologic stage

The pathologic stage describes the size of the oncocytic adrenal cortical carcinoma and whether it has spread. It is assigned after the tumor is removed, using the AJCC staging system, 8th edition. The same system applies to all adrenal cortical carcinomas. The tumor stage (pT) is:

pT1. The tumor is 5 cm or smaller and has not grown outside the adrenal gland.
pT2. The tumor is larger than 5 cm and has not grown outside the adrenal gland.
pT3. The tumor has grown into the surrounding tissue.
pT4. The tumor has grown into a nearby organ or a large vein.

Lymph nodes are not removed in every operation for this cancer. If they were, the report states how many were examined and how many were positive for cancer. The nodal stage is pN0 when none contain cancer and pN1 when at least one does. If no lymph nodes were removed, your report may say pNX or that the nodal stage was not assigned.

Your doctors combine the pathologic stage with your scans to give an overall stage from I to IV. Stages I and II are tumors confined to the adrenal gland. Stage III means growth outside the gland or cancer in nearby lymph nodes. Stage IV means spread to distant organs, most often the liver or lungs.

What is the prognosis?

The outlook for oncocytic adrenal cortical carcinoma is better, on average, than for the usual type of adrenal cortical carcinoma. Most oncocytic tumors are still confined to the adrenal gland when they are found, and they are less likely to spread.

The outlook depends mostly on the stage and on whether all of the tumor could be removed. When the tumor is confined to the adrenal gland and completely removed, about 9 in 10 people are alive five years later. When it has grown outside the gland or spread, about 4 in 10 are alive.

This cancer is rare, so these numbers come from small groups of people. They cannot tell you what will happen to you.

Features in your report that are linked to a higher chance of the cancer coming back include:

Margins. A positive margin or a tumor that was not removed in one piece means some tumor cells may have been left behind.
Ki-67 and grade. A high Ki-67 index or a high grade means the tumor cells are dividing quickly.
Venous invasion. Tumor cells inside a vein can travel to other parts of the body.
Stage. Growth outside the adrenal gland or cancer in lymph nodes means the cancer has started to spread.

Oncocytic adrenal cortical carcinoma can come back years after surgery, which is why follow-up continues for a long time.

What happens after the diagnosis?

A team at a center experienced with adrenal tumors usually plans the care for oncocytic adrenal cortical carcinoma. Your team uses the stage, margins, grade, and Ki-67 index to decide which options to discuss with you.

Follow-up. Follow-up includes regular scans and hormone tests. For many people with a completely removed, low-grade tumor, this is all that is needed.
Mitotane. Mitotane is a drug that acts on adrenal cortical cells. It may be offered after surgery when the chance of the cancer coming back is higher. It is also used when the cancer cannot be removed or has spread.
More surgery or radiation. These may be considered when a margin is positive.
Chemotherapy. Chemotherapy may be offered, often together with mitotane, when the cancer has spread.
Steroid tablets. A tumor that makes extra cortisol can switch off the other adrenal gland. Steroid tablets are often needed until that gland recovers.

Because oncocytic tumors are rare, treatment follows the same approach used for other adrenal cortical carcinomas. The FDA and Health Canada have approved mitotane for adrenal cortical carcinoma that cannot be removed by surgery. Expert guidelines support its use after surgery.

Questions to ask your doctor

Which features made my tumor a carcinoma and not an oncocytoma?
How large was my tumor, and was it removed in one piece?
Had the tumor grown outside the adrenal gland?
Is my tumor low grade or high grade?
What was my Ki-67 index?
Was venous invasion found?
Were the margins negative?
What is the stage of my tumor?
Did my tumor make hormones, and will I need steroid tablets after surgery?
Is mitotane recommended for me, and why or why not?
Has a pathologist who specializes in adrenal tumors reviewed my case?
How often will I need follow-up scans, and for how many years?