Adrenal cancer is a rare type of cancer that develops in the adrenal glands, two small organs situated above each kidney. These glands produce hormones that regulate various bodily functions. Accurately and promptly diagnosing adrenal cancer is important for effective treatment and improved outcomes. This process involves a series of tests and evaluations to distinguish malignant tumors from benign adrenal growths.
Initial Clues
Initial suspicion of adrenal cancer often arises from two main scenarios. Some individuals experience symptoms caused by the tumor’s overproduction of hormones, such as changes associated with Cushing’s syndrome (excess cortisol), Conn’s syndrome (excess aldosterone), or virilization/feminization. General symptoms like abdominal pain, unexplained weight loss, or a palpable mass in the abdomen can also prompt a medical visit. These symptoms are often vague and can be linked to many other less serious conditions.
Alternatively, adrenal tumors are frequently discovered by chance during imaging tests for unrelated medical conditions. These incidentally found masses, known as adrenal incidentalomas, are common. While most adrenal incidentalomas are benign, their discovery necessitates further investigation to rule out malignancy or hormone overproduction.
Blood and Urine Tests
Once an adrenal mass is suspected, blood and urine tests are conducted to assess adrenal gland function and detect hormonal imbalances. These biochemical tests determine if a tumor is “functional,” meaning it produces excessive hormones. Both blood and urine tests are necessary because certain adrenal hormones accumulate differently in the body.
Tests include 24-hour urine collections to measure levels of cortisol, metanephrines, and catecholamines. High cortisol levels might indicate Cushing’s syndrome, while elevated metanephrines and normetanephrines can suggest a pheochromocytoma. Blood tests also evaluate cortisol levels, often involving a dexamethasone suppression test, where a synthetic steroid is given to see if cortisol production suppresses normally. If cortisol levels remain high after dexamethasone, it can point to an overactive adrenal gland. Additional blood tests may include aldosterone-to-renin ratio, potassium, sodium, and sex hormone levels like DHEAS, androstenedione, and testosterone, which can indicate tumors producing these hormones.
Advanced Imaging
Advanced imaging techniques visualize the adrenal glands and characterize any detected masses. Computed Tomography (CT) scans are often the first-line imaging modality, providing detailed images that help identify the mass, its size, location, and initial features. For example, a low density of less than 10 Hounsfield units on an unenhanced CT scan often indicates a benign mass. Features like large size (over 4 cm), irregular margins, or heterogeneous appearance can raise suspicion for malignancy.
Magnetic Resonance Imaging (MRI) offers superior soft tissue contrast and is useful for further characterizing adrenal masses. It can differentiate between lipid-rich adenomas (typically benign) and malignant lesions. Positron Emission Tomography (PET) scans, often combined with CT (PET/CT), assess the metabolic activity of the tumor. Cancer cells typically show higher metabolic activity and accumulate a radioactive sugar tracer more readily, which helps determine if a lesion is cancerous and if it has spread to other parts of the body. While imaging helps locate and characterize tumors, it often cannot definitively distinguish between benign and malignant lesions alone.
Tissue Analysis
Obtaining tissue for pathological examination is often necessary for a definitive diagnosis of adrenal cancer. A biopsy might be considered if imaging and hormonal tests are inconclusive, or if there is concern about metastasis from another primary cancer. However, biopsies of adrenal tumors are generally not preferred due to challenges in distinguishing benign from malignant cells and the risk of complications such as bleeding or spreading tumor cells.
In many cases, surgical removal of the entire mass is the definitive approach to obtaining sufficient tissue for diagnosis. This is particularly true when cancer is highly suspected. A pathologist then examines the tissue under a microscope to identify cancer cells and classify the specific type of adrenal tumor, such as adrenocortical carcinoma. Pathologists look for specific features like high nuclear grade, mitotic rate, atypical mitotic figures, and evidence of invasion into blood vessels or the tumor capsule, using scoring systems like the Weiss criteria to aid in diagnosis.
Confirming the Diagnosis
A definitive diagnosis of adrenal cancer integrates information from symptoms, blood and urine tests, advanced imaging, and tissue analysis. Distinguishing malignant adrenal tumors from benign ones, such as adenomas, presents a significant challenge, as many adrenal masses are non-cancerous. A multidisciplinary collaboration of specialists, including endocrinologists, radiologists, surgeons, oncologists, and pathologists, reviews all findings to reach a conclusive diagnosis.
This team approach ensures a comprehensive evaluation, considering both the hormonal activity and the physical characteristics of the mass. Hormonal testing is recommended for all adrenal masses, even if symptoms of hormone excess are not overt. For small, indeterminate lesions, observation with repeat imaging and biochemical testing may be recommended to monitor for changes before a final decision is made.