This article was last reviewed and updated on April 26, 2018.
by Shaheed Hakim, MD FRCPC
The normal esophagus is lined by specialized cells called squamous cells which form a layer on the inner surface of the esophagus called an epithelium. Squamous cells are very good at protecting tissue against physical forces such as food sliding down your esophagus on its way to your stomach.
Anything that damages the inner lining of the esophagus can lead to a change called inflammation and pathologists use the word esophagitis to describe inflammation of the squamous epithelium. Patients with esophagitis often suffer from pain or difficulty swallowing solid foods. Patients with these symptoms often undergo a procedure known as an upper endoscopy, where a doctor uses a small camera to look at the inner lining of the esophagus.
Biopsies are usually performed in patients with symptoms of esophagitis in order to confirm the diagnosis and to exclude other potential causes.
Esophagitis is a descriptive term and many conditions are known to cause esophagitis.
What causes esophagitis?
GERD: People with acid reflux disease (also known as gastroesophageal reflux disease or ‘GERD’ for short) experience pain when the acids in their stomach move backwards into the esophagus injuring the squamous epithelium.
The microscopic changes associated with this type of injury include spongiosis (swelling), basal cell hyperplasia (an increased number of cells at the bottom of the epithelium), elongation and congestion of lamina propria papillae (congestion), and inflammation. In severe cases, ulceration or erosion of the surface epithelium can be seen.
A diagnosis of acute/active esophagitis means that your pathologist has seen these changes under the microscope and that the changes are consistent with the symptoms or endoscopic findings. GERD is the most common cause of acute/active esophagitis, however, the microscopic features can be seen in other types of esophagitis (see below).
Candida Esophagitis: Candida fungal organisms are a normal part of our gastrointestinal tract (esophagus, stomach, small intestine, and colon). Usually these organisms live on the surface of the tissue without causing any reaction from the tissue below. However in some situations, such as in people with diabetes or those who have recently taken antibiotics, the fungal organisms can increase in number and damage the lining of the esophagus.
When viewed with an endoscope, these damaged areas look like white plaques (a raised area of tissue that stands out from the surrounding normal tissue).
A diagnosis of Candida esophagitis means that your pathologist has seen some or all of the changes of esophagitis (described above), often with increased neutrophils (an inflammatory cell), as well as confirmed the presence of the Candida fungal organisms.
Pathologists often use ‘special stains’ that can highlight these organisms for more easy and accurate identification.
Eosinophilic Esophagitis: Eosinophilic esophagitis is essentially an allergic reaction occurring inside your esophagus. Like in other allergic conditions, allergic esophagitis is associated with the presence of a special type of inflammatory cell called an eosinophil.
A diagnosis of eosinophilic esophagitis means that your pathologist has seen some or all of the features of esophagitis (described above) as well as an increased number of eosinophils.
The diagnosis of eosinophilic esophagitis requires both the microscopic features AND the characteristic endoscopic finding of ‘concentric rings’ or ‘trachealization’ of the esophagus.
Esophagitis that is not treated can damage the squamous epithelium. If the damage continues for many years, a new type of epithelium similar to the epithelium normally found in the small intestine slowly replaces the squamous cells.
The change from squamous epithelium to small intestinal epithelium is an example of metaplasia. This specific type of metaplasia that takes place in the esophagus is referred to as Barrett’s esophagus or Barrett’s disease.
Barrett’s esophagus is a non-cancerous (benign) disease. However, it is considered a precursor because the cells in Barrett’s esophagus have the potential to turn into cancer (a malignant tumour) called adenocarcinoma over time.
Importantly, the risk of developing cancer after a diagnosis of Barrett’s esophagus is low. The presence of dysplasia, a type of abnormal cell growth, in Barrett’s esophagus, increases the risk of cancer (see Dysplasia below).
Dysplasia refers to an abnormal pattern of growth that is initially non-cancerous (benign) but can turn into cancer over time. Long term inflammation which leads to intestinal metaplasia, can then lead to dysplasia.
The earliest change is referred to as low-grade dysplasia. In some cases, the cells become even more abnormal and progress to high-grade dysplasia.
In high grade dysplasia, the abnormal cells look similar to cancer cells but are only seen in the epithelium. Once the cells have entered the tissue below the epithelium, the diagnosis changes to ‘intramucosal carcinoma’, which is essentially an early stage cancer.
Your pathologist will carefully examine the tissue for any evidence of dysplasia.