ECL (Enterochromaffin-like) Cell Hyperplasia: Definition

ECL cell hyperplasia means that the number of enterochromaffin-like (ECL) cells in the lining of the stomach has increased. ECL cells are a type of neuroendocrine cell, and they help control how much acid the stomach makes. “Hyperplasia” simply means an increase in the number of cells.

ECL cell hyperplasia is a description of something the pathologist saw under the microscope, not a diagnosis on its own. The cells themselves are not cancer, and they are not abnormal in the way that precancerous cells are. Instead, this finding is a clue that something else is changing the way the stomach makes acid. For that reason, the most useful question is not “how bad is the hyperplasia?” but “what is causing it?” This article explains what ECL cells do, what causes their numbers to increase, and what the finding means when it appears on a pathology report.

What are ECL cells and what do they do?

ECL cells are found in the oxyntic mucosa, the specialized lining in the upper and middle parts of the stomach where acid is produced. Their job is to release histamine, a chemical messenger that tells the acid-producing cells nearby to make stomach acid.

ECL cells are controlled by a hormone called gastrin, which is made in the lower part of the stomach. Gastrin and ECL cells work together in a feedback loop that keeps stomach acid at the right level:

When the stomach needs more acid, gastrin levels rise.
Gastrin signals the ECL cells to release histamine.
Histamine tells the acid-producing cells to make acid.
When enough acid is present, gastrin levels fall again.

Understanding this loop explains almost everything about ECL cell hyperplasia. Gastrin does not only tell ECL cells to release histamine; it also encourages them to grow and multiply. So when gastrin levels stay high for a long time, the number of ECL cells increases. That increase is what pathologists call ECL cell hyperplasia.

What causes ECL cell hyperplasia?

Almost all ECL cell hyperplasia is caused by gastrin levels staying high over a long period. This usually happens for one of two reasons: the stomach is making less acid than normal (so the body keeps signaling for more), or something is producing gastrin directly. Common causes include:

Chronic atrophic gastritis — Long-term inflammation damages and gradually removes the acid-producing cells in the stomach lining. With less acid being made, gastrin levels rise and ECL cells increase. This is especially common in the autoimmune form, in which the immune system attacks the acid-producing cells.
Long-term use of acid-reducing medication — Proton pump inhibitors (PPIs), such as omeprazole and pantoprazole, work by lowering stomach acid. Because acid is low, the body responds by making more gastrin, which over time increases the number of ECL cells. This is a common and expected effect of these medications.
Zollinger-Ellison syndrome — A rare condition in which a tumor (called a gastrinoma) makes large amounts of gastrin. The constant high gastrin level drives a marked increase in ECL cells.
Long-term Helicobacter pylori infection — When this bacterial infection involves the upper part of the stomach over many years, it can reduce acid production and raise gastrin levels.

What does ECL cell hyperplasia look like under the microscope?

Pathologists describe ECL cell hyperplasia by how the extra cells are arranged in the stomach lining, because the pattern reflects how much the cells have increased:

Linear hyperplasia — The extra ECL cells form short chains or lines along the stomach glands. This is the milder pattern and carries a lower risk of progressing further.
Nodular hyperplasia — The extra ECL cells gather into small clusters or nodules. This pattern reflects a greater increase in cell numbers and is watched more closely.

ECL cells can be hard to pick out on routine stains, so pathologists often confirm the finding using immunohistochemistry, a test that uses special stains to detect specific proteins. Two stains are commonly used:

Chromogranin A — Positive staining confirms that the cells are neuroendocrine cells and makes them easier to count.
Synaptophysin — Another stain that highlights neuroendocrine cells.

Does ECL cell hyperplasia cause symptoms?

ECL cell hyperplasia does not cause symptoms on its own. It is usually found by chance when a stomach biopsy is taken for another reason. Any symptoms a person has come from the underlying condition rather than from the increased number of ECL cells. For example, chronic atrophic gastritis can cause bloating or mild abdominal discomfort, and because it can interfere with the absorption of vitamin B12 and iron, it can also lead to anemia. Zollinger-Ellison syndrome, in contrast, causes very high acid levels and can lead to repeated stomach ulcers, abdominal pain, reflux, and diarrhea.

What does it mean if ECL cell hyperplasia is found in my biopsy?

Finding ECL cell hyperplasia tells your doctor that gastrin levels have likely been high for some time. The main value of the finding is that it prompts a look for the cause. Depending on the situation, this may involve blood tests to measure gastrin and vitamin B12, tests for Helicobacter pylori, tests for autoimmune gastritis, or a review of any acid-reducing medications you take.

ECL cell hyperplasia is also the change that can, in some people, come before a neuroendocrine tumor of the stomach develops. It is important to keep this in perspective, because the level of risk depends almost entirely on the cause:

Chronic atrophic gastritis and Zollinger-Ellison syndrome — These conditions carry the clearest link to stomach neuroendocrine tumors, and people with them are usually followed with periodic endoscopy. Tumors that do develop in this setting are typically small, slow-growing, and often managed with monitoring or endoscopic removal.
Long-term acid-reducing medication — ECL cell hyperplasia is common in people taking PPIs for a long time, but progression to a neuroendocrine tumor appears to be very rare. Large reviews of clinical trials have not shown an increased risk of stomach cancer or precancerous changes from long-term PPI use, and reports of neuroendocrine tumors in PPI users without another underlying cause are unusual.

Because the finding on its own does not indicate cancer, decisions about follow-up and about whether to continue or adjust any acid-reducing medication are made with your doctor based on the underlying cause and your overall situation. Do not stop a prescribed medication on your own.

Questions to ask your doctor

What is causing the ECL cell hyperplasia in my stomach?
Was the pattern described as linear or nodular?
Do I have chronic atrophic gastritis, and was it the autoimmune type?
Should my gastrin level or vitamin B12 level be checked?
Was I tested for Helicobacter pylori infection?
If I take an acid-reducing medication, should it be reviewed or changed?
Do I need any follow-up endoscopy or biopsies, and how often?
Does this finding change my risk of developing a stomach tumor?