by Jason Wasserman MD PhD FRCPC
January 22, 2024

A radicular cyst, also known as a periapical cyst, is the most common type of odontogenic cyst. It typically develops at the apex (tip) of a tooth’s root. Usually, it’s associated with a non-vital (dead) tooth, often as a result of dental decay, trauma, or other factors leading to nerve death in the tooth.

How is this diagnosis made?

This diagnosis often involves a combination of dental examination, imaging, and microscopic analysis.

What causes a radicular cyst?

The primary cause of a radicular cyst is a chronic infection in the pulp (innermost part) of the tooth. This situation often arises from:

• Dental caries (tooth decay): Deep decay can lead to the death of the tooth nerve, creating an environment for cyst formation.
• Trauma: Injury to a tooth that affects the pulp can lead to the development of a cyst.
• Previous dental work: Sometimes, dental procedures, especially those involving the tooth pulp, can inadvertently lead to cyst formation.

Symptoms of a radicular cyst

Radicular cysts can often grow without presenting any symptoms, especially in their early stages. When symptoms do occur, they may include:

• Swelling in the jaw: Noticeable bump or swelling in the jawline.
• Pain or discomfort: Although not always painful, some individuals may experience discomfort, especially if the cyst becomes infected.
• Displacement of teeth: Large cysts might displace surrounding teeth.
• Pressure: Feelings of pressure in the affected area.
• Tooth sensitivity: Particularly to hot or cold stimuli.

In some cases, the cyst can lead to the destruction of bone, weakening the jaw’s structure.

Microscopic features

Under microscopic examination, a radicular cyst appears as an open space lined by stratified squamous epithelium, which may be of variable thickness. The wall of the cyst is made up of fibrous tissue which often contains inflammatory cells, mainly lymphocytes and plasma cells. Cholesterol clefts (spaces filled with cholesterol) are often found in the wall of the cyst. The presence of these features, along with the clinical history and radiographic findings, aids in the definitive diagnosis of a radicular cyst.

About this article

This article was written by medical doctors in conjunction with patient advisers. It was designed to help patients read and understand their pathology reports. If you have any questions about this article, please contact us.

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