CMV Esophagitis: Understanding Your Pathology Report

by Jason Wasserman MD PhD FRCPC
July 25, 2025

CMV esophagitis is a condition in which the esophagus becomes infected by a virus called cytomegalovirus (CMV). This infection causes inflammation and damage to the tissue lining the esophagus, leading to pain and difficulty swallowing.

CMV is a member of the herpesvirus family. It is a common virus that many people carry in their body without knowing it. In healthy individuals, CMV usually remains inactive and does not cause symptoms. However, in people with a weakened immune system, the virus can reactivate and lead to infections in various parts of the body, including the esophagus.

What causes CMV esophagitis?

CMV esophagitis is caused by infection of the esophagus with the cytomegalovirus (CMV). The virus infects certain cells in the lining of the esophagus, causing them to become damaged or destroyed. The body responds by sending immune cells to the area, which leads to inflammation.

Who is at risk for developing CMV esophagitis?

This condition is most often seen in people with weakened immune systems. This includes:

• People who have had organ or bone marrow transplants and take medications to suppress the immune system.

• People receiving chemotherapy or long-term corticosteroid therapy.

• People living with HIV or AIDS.

• Patients taking medications known as immune modulators that affect how the immune system functions.

CMV esophagitis is rare in people with a normal, healthy immune system.

What are the symptoms of CMV esophagitis?

Symptoms of CMV esophagitis can include:

• Painful swallowing (called odynophagia).

• Difficulty swallowing (called dysphagia).

• Chest pain.

• Fever (in some cases).

• Weight loss or poor appetite (especially in people with long-standing symptoms).

If left untreated, CMV esophagitis can lead to ulcers and more serious complications in the esophagus.

How is CMV esophagitis diagnosed?

CMV esophagitis is usually diagnosed during a procedure called an upper endoscopy. During this procedure, your doctor passes a thin, flexible tube with a camera (called an endoscope) into your esophagus to look for signs of infection or inflammation.

If CMV esophagitis is suspected, your doctor may see white patches or ulcers (open sores) on the inside surface of the esophagus. A biopsy will be taken from one or more of these areas. This means that a small piece of tissue is removed and sent to a pathologist to be examined under a microscope.

What does CMV esophagitis look like under the microscope?

The inner lining of the esophagus is made up of flat cells called squamous cells, which form a protective layer called the epithelium. Just beneath this layer is the lamina propria, a layer of connective tissue that contains blood vessels, fibroblasts (support cells), and immune cells.

In CMV esophagitis, CMV infects cells beneath the surface, especially:

• Endothelial cells, which line the blood vessels.

• Fibroblasts, which provide structural support.

When pathologists examine these infected cells under a microscope, they see several distinctive features:

• The infected cells often have an enlarged nucleus (the central part of the cell that contains DNA).

• Inside the nucleus, there are blue or purple viral inclusions—a telltale sign of CMV infection.

• The surrounding tissue often shows signs of inflammation, with many immune cells like neutrophils, lymphocytes, and histiocytes gathering in response to the infection.

These changes help pathologists confirm the diagnosis of CMV esophagitis.

What other tests may be performed to confirm the diagnosis?

To be sure that CMV is the cause of the infection, your pathologist may perform a test called immunohistochemistry (IHC). This test uses antibodies that attach to CMV proteins inside infected cells. When the antibodies are added to the tissue, they produce a visible stain that highlights infected cells under the microscope.

IHC testing is especially useful when the diagnosis is unclear or when viral inclusions are difficult to see. A positive IHC test confirms the presence of CMV in the esophageal tissue.

How is CMV esophagitis treated?

CMV esophagitis is treated with antiviral medications, such as ganciclovir or valganciclovir. These medications help slow the virus and allow the esophagus to heal. Treatment is especially important in people with weakened immune systems. In severe cases or when oral medication is not possible, the drugs may be given through an IV.

Doctors may also adjust or temporarily reduce immune-suppressing medications (if possible) to help the body fight the infection.

Questions to ask your doctor

• What test confirmed that I have CMV in my esophagus?

• Is my immune system a contributing factor?

• What treatment do you recommend, and how long will I need it?

• Are there any complications I should watch for?

• Will I need follow-up tests or another endoscopy?

• What can I do to prevent this from happening again?