High grade squamous dysplasia of the esophagus

by Jason Wasserman MD PhD FRCPC
January 18, 2025


High grade squamous dysplasia of the esophagus is a precancerous condition in which the cells lining the inside of the esophagus show significant abnormal growth. These cells are called squamous cells, and they normally form a thin, protective layer called the squamous epithelium. In high grade squamous dysplasia, the squamous cells look very different from normal cells and show more advanced changes compared to low grade squamous dysplasia. If not treated, high grade squamous dysplasia is associated with a higher risk of progressing to a type of esophageal cancer squamous cell carcinoma.

High grade squamous dysplasia

What are the symptoms of high grade squamous dysplasia of the esophagus?

High grade squamous dysplasia may not cause symptoms, particularly in its early stages. However, symptoms might occur if the underlying condition causing the dysplasia has progressed.

These symptoms can include:

  • Difficulty swallowing (dysphagia).
  • Heartburn or acid reflux.
  • Pain when swallowing.
  • A sensation of food getting stuck in the esophagus.

Because it often does not cause noticeable symptoms, high grade squamous dysplasia is typically found during an upper endoscopy performed for other reasons.

What causes high grade squamous dysplasia of the esophagus?

High grade squamous dysplasia is caused by damage to the squamous cells lining the esophagus. The most common causes include:

  • Chronic acid reflux (gastroesophageal reflux disease or GERD): Long-term exposure to stomach acid can damage the squamous epithelium.
  • Smoking: Tobacco use is a major risk factor for squamous dysplasia.
  • Alcohol use: Heavy drinking can irritate and damage the esophageal lining.
  • Chronic irritation or inflammation: This can result from repeated exposure to hot liquids, spicy foods, or other irritants.

Addressing these causes can help reduce the risk of progression to cancer.

How is this diagnosis made?

High grade squamous dysplasia is diagnosed by examining a small tissue sample taken from the esophagus during an upper endoscopy. The sample is prepared and analyzed under a microscope by a pathologist, who looks for specific changes in the cells and their arrangement to confirm the diagnosis.

What are the microscopic features of high grade squamous dysplasia of the esophagus?

The esophagus is lined by squamous epithelium, a thin layer of flat cells called squamous cells. In high grade squamous dysplasia, these cells show significant changes in both their appearance and organization.

When examining the tissue, the pathologist looks for:

Changes in the squamous cells (cytological atypia):
  • Larger and irregularly shaped nuclei (the part of the cell that contains DNA).
  • Darker staining of the nuclei, a sign of increased activity.
  • Loss of normal organization, with cells no longer aligning neatly.
  • Overlapping of cells causes a crowded appearance.
Changes in the squamous epithelium (architectural atypia):
  • Abnormal maturation, where cells no longer develop normally as they move through the layers of the epithelium

High grade squamous dysplasia is diagnosed when these changes involve more than half of the thickness of the squamous epithelium or when the abnormalities in the cells are severe, even if they are limited to a smaller area.

What is the risk of developing esophageal cancer with high grade squamous dysplasia?

High grade squamous dysplasia has a significant risk of progressing to a type of esophageal cancer called squamous cell carcinoma if left untreated. This condition is considered one of the final steps before cancer develops, which is why early detection and treatment are so important.

The exact risk of progression depends on factors such as your overall health, lifestyle habits like smoking or alcohol use, and how effectively the underlying cause of the dysplasia is managed.

Regular monitoring with endoscopies and biopsies is crucial for people diagnosed with high grade squamous dysplasia. Treatment options, such as removing or destroying the abnormal tissue, may be recommended to prevent progression to cancer.

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