Adrenal Cortical Adenoma: Understanding Your Pathology Report

Section Editor: Jason Wasserman MD PhD FRCPC
May 29, 2026

An adrenal cortical adenoma is a benign (non-cancerous) tumor that develops from cells in the adrenal cortex, the outer part of the adrenal gland. There are two adrenal glands in the body, one on top of each kidney. The adrenal cortex normally produces hormones that help control blood pressure, salt and water balance, metabolism, sexual development, and the body’s response to stress.

Adrenal cortical adenomas are very common. About 5 percent of adults have at least one adrenal cortical nodule that can be seen on imaging, often discovered by chance during a CT or MRI performed for an unrelated reason. The term adrenocortical adenoma means the same thing as adrenal cortical adenoma and may also appear on pathology reports. Some adrenal cortical adenomas produce excess hormones and cause symptoms; others are silent and require no treatment beyond ongoing monitoring.

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

What causes an adrenal cortical adenoma?

Most adrenal cortical adenomas develop sporadically, meaning they appear without a known cause and are not linked to anything the person did or was exposed to. Both random genetic changes within the tumor cells and ordinary differences between individuals likely contribute. Tobacco use has been associated with a slightly higher risk of adrenal cortical tumors, but the link is not strong.

A small number of adrenal cortical adenomas arise in people who carry an inherited genetic change. Inherited causes are more likely when the patient is young, when adenomas are present in both adrenal glands, when several adenomas are present, or when there is a family history of related tumors. The most relevant inherited conditions include:

Multiple endocrine neoplasia type 1 (MEN1) — Adrenal cortical tumors are common in MEN1, although most are benign.
Familial hyperaldosteronism (FH-I, FH-II, FH-III, FH-IV) — A group of inherited conditions in which aldosterone-producing adrenal tumors run in families.
Carney complex — A rare hereditary condition associated with adrenal tumors and several other endocrine and skin abnormalities.
Beckwith-Wiedemann syndrome and Li-Fraumeni syndrome — Inherited conditions more often associated with adrenal cortical carcinoma than with adenoma, but adenomas can also occur.

The current World Health Organization (WHO) classification, published in 2022, also recognizes a group of related conditions called adrenal cortical nodular disease, in which multiple nodules develop in one or both adrenal glands. These conditions differ from a solitary adenoma and are noted separately in the pathology report when present.

What are the symptoms of an adrenal cortical adenoma?

The symptoms depend on whether the tumor produces hormones. Many adenomas are silent and cause no symptoms at all. When the tumor produces hormones, the symptoms depend on which hormone is produced.

Aldosterone-producing adenoma

Some adenomas produce excess aldosterone, a hormone that controls salt and water balance. This condition is called primary aldosteronism or Conn syndrome. Aldosterone-producing adenomas are an important treatable cause of high blood pressure and may also lower blood potassium levels. Symptoms can include high blood pressure (often difficult to control with usual medications), muscle weakness, cramps, fatigue, headache, palpitations, increased thirst, and frequent urination. Many patients have normal potassium levels despite excess aldosterone. Because excess aldosterone can come from one adrenal gland or from both, additional testing (including a procedure called adrenal venous sampling in selected cases) may be needed to decide whether surgery on one gland is likely to help.

Cortisol-producing adenoma

Some adenomas produce excess cortisol, a hormone involved in metabolism and stress response. Severe cortisol excess causes Cushing syndrome, with symptoms that include weight gain (especially around the abdomen and face), a rounded face, muscle weakness, easy bruising, thinning skin with purple stretch marks, high blood pressure, high blood sugar, thinning bones, and an increased risk of infections. In children, slowed growth can be an important early clue. Other adenomas produce only small amounts of excess cortisol; this is called mild autonomous cortisol secretion and may not cause obvious symptoms but can still raise the risk of high blood pressure, high blood sugar, and bone loss over time.

Sex hormone-producing adenoma

Adrenal cortical adenomas that produce sex hormones (androgens or estrogens) are very rare. Androgen excess in women can cause increased facial and body hair, deepening of the voice, irregular menstrual cycles, or virilization. Estrogen excess in men can cause breast enlargement. Because sex hormone production is uncommon in benign adenomas, the pathology team carefully evaluates these tumors to exclude adrenal cortical carcinoma.

Nonfunctioning adenoma

Many adrenal cortical adenomas do not produce hormones and cause no symptoms. These are most often found by accident on CT or MRI scans performed for another reason. Imaging features such as size, fat content, and how the tumor handles contrast dye help doctors decide whether a nodule is likely to be a benign adenoma or whether further evaluation is needed.

How is the diagnosis made?

The workup usually begins when an adrenal mass is found on an imaging study or when blood tests show a hormone imbalance. Blood and urine tests measure cortisol, sex hormones, aldosterone, and catecholamine metabolites (the hormones produced by the adrenal gland’s inner part, the medulla). These tests determine whether the tumor is producing hormones and help rule out pheochromocytoma, a different type of adrenal tumor that arises from the medulla. Imaging tests, most often CT and MRI of the abdomen, are used to evaluate the size, appearance, and behavior of the tumor.

Most small, non-functioning adrenal cortical adenomas with typical imaging features do not require surgical removal. They are usually monitored with repeat imaging and hormone testing. When the tumor is removed surgically (most often because it is producing hormones, is enlarging, or has features that make adrenal cortical carcinoma a concern), the diagnosis is made after the tumor has been examined under the microscope by a pathologist.

Under the microscope, the pathologist’s most important task is to confirm that the tumor is a benign adenoma rather than an adrenal cortical carcinoma. The two can look similar in some cases, and the distinction depends on a combination of features rather than any single finding. Pathologists use structured scoring systems (most commonly the Weiss score, described in a section below) to support the diagnosis. Immunohistochemistry, which uses antibodies to detect specific proteins in tissue, is used to confirm that the tumor arises from the adrenal cortex and to exclude other tumors that can involve the adrenal gland, such as pheochromocytoma, metastatic cancer from another organ, or renal cell carcinoma. The most reliable marker confirming adrenal cortical origin is SF1. Other supportive markers include melan-A, inhibin, calretinin, and synaptophysin.

Microscopic features that may be described in your report

Under the microscope, an adrenal cortical adenoma is a well-circumscribed tumor made of cells that resemble normal adrenal cortex. The pathology report may describe one or more of the following features:

Clear cells — Pale cells with abundant fat-like droplets in the cytoplasm. Clear cells resemble those of the outer adrenal cortex (the zona fasciculata) and make up the majority of cells in most adenomas.
Compact (eosinophilic) cells — Cells with denser, pinker cytoplasm that resemble those of the inner adrenal cortex (the zona reticularis). Many adenomas contain a mixture of clear and compact cells.
Oncocytic change — A finding in which the cells have abundant bright pink cytoplasm because they are filled with energy-producing structures called mitochondria. Some adenomas are predominantly oncocytic; these are sometimes called adrenal cortical oncocytomas and may be functional or non-functional.
Pigment (black adenoma) — Some adenomas contain a brown-black pigment called lipofuscin, giving the tumor a dark color when seen by the naked eye.
Myxoid change — A finding in which the cells are surrounded by a sticky, gel-like material called myxoid stroma. This can occasionally make the diagnosis more difficult and may require additional special stains to confirm.
Atrophic surrounding cortex — In cortisol-producing adenomas, the normal adrenal cortex around the tumor often becomes thin because the rest of the gland is suppressed by the excess cortisol. The pathology report may describe this finding as supportive of autonomous cortisol production.
Intact reticulin framework — A special stain called reticulin highlights the supporting fiber network that surrounds groups of tumor cells. In a benign adenoma, this network is preserved; in adrenal cortical carcinoma, it is broken up or lost.

The Weiss score: distinguishing adenoma from carcinoma

The Weiss score is a tool that pathologists use to help decide whether an adrenal cortical tumor is a benign adenoma or a malignant adrenal cortical carcinoma. This decision is important because adenomas and carcinomas behave and are treated very differently.

The pathologist examines the tumor for nine features. Each feature counts as one point, and the points are added together to give a total score:

High nuclear grade — The tumor cell nuclei look large, dark, and irregular compared with normal adrenal cells.
Increased mitotic activity — More than 5 dividing tumor cells (mitotic figures) in a defined area, indicating faster growth.
Atypical mitotic figures — Dividing cells with an abnormal shape or pattern.
Necrosis — Areas where tumor cells have died.
Diffuse architecture — Tumor cells growing in large, solid sheets rather than in smaller, organized clusters.
Low proportion of clear cells — Clear, fat-containing cells make up less than 25 percent of the tumor.
Capsular invasion — Tumor cells growing into or through the fibrous capsule that surrounds the tumor.
Sinusoidal invasion — Tumor cells inside small blood-filled spaces within the tumor.
Venous invasion — Tumor cells inside a vein.

How the score is interpreted:

Score 0 to 2 — Supports a diagnosis of adrenal cortical adenoma.
Score 3 or higher — Supports a diagnosis of adrenal cortical carcinoma.

No single feature on its own determines whether a tumor is benign or malignant; the overall pattern across the nine features is what matters. For tumors with predominantly oncocytic cells, a different scoring system, the Lin-Weiss-Bisceglia system, is used because some features that would be worrisome in a conventional tumor (such as large pink cytoplasm or prominent nucleoli) are part of the normal appearance of oncocytic cells. Other systems, including the Helsinki score and the reticulin algorithm, may also appear on the pathology report.

Aldosterone-producing tumors and CYP11B2

In aldosterone-producing adrenal cortical adenomas, the pathologist may use a special stain called CYP11B2 to identify the cells that are actually making aldosterone. CYP11B2 is the enzyme that produces aldosterone, and the stain highlights only the cells that contain it. This is part of an approach called the HISTALDO classification, introduced to help explain why aldosterone-producing adrenal tumors can vary in their behavior after surgery.

CYP11B2 staining can show several patterns:

A single nodule with strong CYP11B2 staining — Supports the diagnosis of a classic aldosterone-producing adenoma. Patients with this pattern are more likely to be cured of their high blood pressure after surgery.
Multiple small nodules or scattered clusters of CYP11B2-positive cells — Suggests that aldosterone production comes from several different areas in the gland rather than a single tumor. This finding may explain why some patients continue to have high blood pressure or aldosterone excess after surgery, even when the main tumor has been completely removed.

CYP11B2 staining is not performed in every laboratory, and, when available, the results are used alongside imaging findings, surgical outcome, and the patient’s response to determine the best long-term plan.

What is the prognosis?

Adrenal cortical adenomas are benign tumors with an excellent prognosis. They do not spread to other parts of the body, and a single non-functioning adenoma that has been completely removed almost never returns.

For hormone-producing tumors, the long-term prognosis depends on whether the hormone excess is corrected and on any health problems caused by it before surgery. Uncontrolled cortisol excess can cause lasting effects on bone density, blood pressure, and metabolism. Long-standing aldosterone excess increases the risk of cardiovascular disease, even after the tumor is removed, and continued blood pressure management is often needed. Identifying and treating the underlying hormone imbalance is essential.

What happens after this diagnosis?

The pathology findings and the hormone status guide the next steps in care:

Treatment of hormone excess — If the tumor was producing aldosterone or cortisol, surgery to remove the affected adrenal gland often improves or resolves the hormone imbalance. Some patients also need temporary steroid replacement after surgery, particularly after removal of a cortisol-producing tumor, because the unaffected adrenal gland has been suppressed and takes time to recover.
Monitoring of small or non-functioning adenomas — Many adrenal cortical adenomas that are small and not producing hormones do not need to be removed. They are monitored with repeat imaging and hormone testing at intervals decided by the treatment team. The first follow-up is often within the first year, with longer intervals if the nodule is stable.
Blood pressure and metabolic management — Patients who had high blood pressure, high blood sugar, or bone loss before surgery may need ongoing treatment for these conditions even after the tumor is removed.
Genetic counseling — Considered when the patient is young, when adenomas are present in both adrenal glands or multiple sites, or when there is a relevant family history. The results may guide screening for the patient and for family members.
Multidisciplinary care — Endocrinology, endocrine surgery, and (when relevant) genetics work together to plan treatment and follow-up.

Questions to ask your doctor

Is my adrenal cortical adenoma producing hormones, and which ones?
Was the tumor entirely benign, and was the diagnosis of carcinoma excluded?
What was my Weiss score, and what does it mean?
If my tumor produced aldosterone, was a CYP11B2 stain performed, and what did it show?
If my tumor produced cortisol, will I need temporary steroid replacement after surgery?
If my tumor was not removed, how often do I need follow-up imaging and hormone testing?
Will my blood pressure improve after surgery, and will I still need blood pressure medication?
Did the tumor have unusual features, such as oncocytic change or myxoid change?
Are there features in the surrounding adrenal cortex that the pathologist commented on?
Should I be evaluated for an inherited condition based on my findings?
Should my family members be screened for related conditions?
What follow-up testing or imaging do I need over the long term?