How Adenoid Cystic Carcinoma Is Diagnosed

Adenoid cystic carcinoma (ACC or AdCC) is diagnosed after a series of tests and a biopsy. This rare form of cancer most often develops in the salivary glands, but it may also form elsewhere in the body.

Certain tests like imaging tests can help your doctor determine whether the cancer has spread. Imaging tests can also give details about the tumor size, type, and cancer stage. This article describes how adenoid cystic carcinoma is diagnosed. 

Not every test below will be needed to confirm the diagnosis. Your doctor will decide which are necessary in your situation based on your signs and symptoms (like bleeding from the mouth or a persistent sore) and overall health.

Self-Checks

It can be particularly difficult to self-check for this type of uncommon cancer because the tumors are relatively slow growing. That said, there are ways of monitoring changes within your body and noticing abnormalities, or anything odd, early on.

ACC is most common in the major salivary glands, which are located in your head and neck. 

Here’s how to self-check the head and neck area:

• Take a look inside your mouth during your daily oral hygiene routine (brushing, flossing, using mouthwash). 
• Check everywhere you can for any signs of changes to the area. Changes include differences in color or texture, or bumps, lumps, and growths. Areas to check in particular are under the tongue, on the roof and floor of your mouth, and inside your cheeks. 
• Lift your upper lip or bring down your lower lip and look for changes.
• Feel around your lymph nodes for swelling, tenderness, or lumps. Lymph nodes are the glands that get swollen when you’re sick. They are part of your immune system, which helps fight infection and disease in different areas in your body.

Physical Examination

A physical examination done by an ear, nose, and throat specialist (otolaryngologist, or ENT) can be used to get a sense of localized issues and see if a biopsy (removing a sample of tissue for further examination) and further testing are necessary. 

Your ENT will do a thorough physical examination of your head and neck area in the case of suspected salivary gland ACC. The doctor will pay particular attention to the three major salivary glands that can become sick from ACC: 

• Parotid gland (largest of the three)
• Submandibular gland
• Sublingual gland

During your physical exam, you may be asked about symptoms experienced and asked to give an updated medical history. 

Your ENT may decide to take a closer and deeper look inside your throat. The doctor will do this with a thin, flexible, lighted instrument called an endoscope. Endoscopes are inserted into your mouth and down your throat to give the doctor a better view.

Labs and Tests

Routine lab work will be ordered to rule out other potential causes of your symptoms (especially because ACC is so uncommon). These are not considered diagnostic tests, though, because there is no blood test for ACC.

However, blood tests can show whether your body is fighting an infection, and this is helpful in directing your doctor’s treatment plan.

A complete blood count test (CBC) panel is often performed. It checks levels of cells produced by the bone marrow in the blood, including markers of health like:

• Red blood cells: A low count signals anemia.
• White blood cells: A low count (leukopenia) increases infection risk because it signals immunosuppression, or immune system dysfunction.
• Platelets: A low count (thrombocytopenia) signals blood clotting problems.

A comprehensive metabolic panel (CMP) makes note of the following:

• Fluid balance
• Electrolyte levels
• Blood sugar
• Protein levels
• Liver functioning
• Kidney functioning

Other tests include:

• Tumor blood markers: These markers are the chemicals released by tumors, although tumors don’t always mean the person has cancer.
• Circulating tumor cell (CTC) test: Another way of testing to see signs of normal cells transforming into cancer cells.
• Gene testing (genomic testing): Gene testing gives your doctor an idea of the likelihood of your developing cancer during your lifetime. It does not tell you whether you’ll develop cancer, only if you have more risk compared to others.

Biopsy

A biopsy is a procedure in which the abnormal cells are sampled and sent for testing. ​​This test will help your doctor determine a diagnosis and next steps. There are a few different biopsy methods that can be used:

• Fine needle biopsy: A thin needle is inserted to remove fluid and cells from the area.
• Surgical removal: Part or all of a tumor is removed with the use of a scalpel (surgical knife) or laser cutting tool.

The biopsy is then prepared in the laboratory for microscopic examination by a pathologist (a doctor who specializes in laboratory medicine, including tissue testing).

Imaging

There are ways your doctor can look inside your head and neck and take pictures of the area for further examination. You may not need all of these tests, but it’s likely your doctor will want to use magnetic resonance imaging (MRI) or a computed tomography (CT) scan to check the tumor before performing a biopsy.

Magnetic Resonance Imaging (MRI)

An MRI uses magnetic fields to create images of the area in which to measure tumor sizes. If you have an MRI, you’ll be given a dye called a contrast medium via an injection so a detailed image can be produced. MRIs can be used to see if the ACC has spread to your central nervous system.

Positron-Emission Tomography (PET) or PET-CT Scan

A PET scan is usually combined with a CT scan (PET-CT scan). Instead of contrast dye, you’ll drink a minimal amount of a radioactive sugar substance. Cancer cells feed on this for energy. As such, they’ll readily take more of this up than other cells. Your doctor can then see the difference and determine cancer staging, which is a determination of size and location of the tumor and whether the cancer has spread.
 

Cancer Staging 

Cancer staging is when your doctor translates all the information from the above tests into the TNM system to describe the tumor. 

The TNM system covers:

• Tumor size (T plus a number or letter to describe size and location): Tumor size is usually measured in centimeters.
• Node (N plus a number or letter to describe size and location): Nodes refer to the small, bean-shaped connector organs (lymph nodes) in your immune system that fight infection. If the node is close to the tumor, it’s called a regional node. Nodes farther away are called distant lymph nodes. 
• Metastasis (M plus a letter or number): This indicates if the cancer has spread and is measured from X (meaning it cannot be evaluated) to M1 (it has spread to other areas).

Cancer Stages

Your doctor will discuss cancer stages after they have made their final assessment. Their diagnosis takes into account your results from all the tests combined.

Stage 1: Noninvasive tumor (T1 or T2) with no spread to lymph nodes (N0) and no distant metastasis (M0)

Stage 2: Invasive tumor (T3) with no spread to lymph nodes (N0) or distant metastasis (M0)

Stage 3: Smaller tumor (T1 or T2) that has spread to regional lymph nodes (N1) but shows no sign of metastasis (M0)

Stage 4A:

• A T invasive tumor (T4a) that either has no lymph node involvement (N0), or has spread to only a single, same-sided lymph node (N1) but with no metastasis (M0)
• Or, a T3 tumor with one-sided nodal involvement (N1) but no metastasis (M0), or any tumor (any T) with extensive nodal involvement (N2) but no metastasis (M0)

Stage 4B: Any cancer (any T) with more extensive spread to lymph nodes (N2 or N3) and no metastasis (M0)

Stage 4C: Any cancer (any T, any N) with distant metastasis (M1)

Recurrent: If the cancer returns, these tests and scans can be used to confirm this diagnosis again and update staging details. 

Differential Diagnosis

Differential diagnosis indicates possible other conditions that might produce a patient's symptoms and signs. When it comes to ACC in the salivary glands, there are many potential differential diagnoses.

They include:

• Common canker sore (aphthous ulcer)
• Basaloid squamous carcinoma (a form of esophageal cancer)
• Adenoid cystic carcinoma of the esophagus (unlikely due to "true" ACC of the esophagus being extremely rare)
• Herpes simplex viruses 
• Autoimmune concerns (such as Behcet's disease or lupus erythematosus)

The National Organization of Rare Disorders says benign (noncancerous) growths may appear similar to ACC tumors but show other signs that make them different from cancerous tumors.

Summary

Adenoid cystic carcinoma is diagnosed through physical examination, imaging, and biopsy. If this rare type of cancer is discovered, the physician will use the information to give the cancer a stage and grade, which will help guide treatment.

A Word From Verywell

Always remember that you are your own best advocate. Give yourself time to digest the information you are receiving while going through the diagnostic process. Ask your doctor any questions that arise and to clarify unfamiliar terms.

If you have been diagnosed with ACC, talk to your doctor about treatment concerns and recovery questions. Joining a support group or discussing your diagnosis with a mental health professional who can help you process the information and what it means can also be helpful.