squamous cell

Meaning of squamous cell: Squamous cells are flat, scale like cells that form the surface layer of skin and the lining of many internal passages.

Definition of squamous cell

A squamous cell is a flat cell with a scale like appearance under the microscope, and cells of this type form thin, sheet-like layers covering both outer and inner body surfaces. On the skin, squamous cells make up the outermost layer of the epidermis, providing a protective barrier against the external environment.

Squamous cells also line many of the body's hollow structures and passages, including the airways of the respiratory tract, portions of the digestive tract, and parts of the urinary and reproductive systems. Their flattened shape allows them to fit closely together, forming a smooth, continuous surface that resists friction and helps limit the passage of substances across it.

Because squamous cells are found in so many locations, cancers arising from them, called squamous cell carcinomas, can develop in a wide range of body sites, including the skin, lungs, esophagus, cervix, and head and neck.

Used in a sentence

Pathology confirmed squamous cells consistent with the normal lining of the esophagus.

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Good to know

The presence of squamous cells is normal and expected in many body linings, so finding them on a laboratory report is significant mainly in the context of where they were found and whether their appearance is abnormal.

Word origin

Where “squamous cell” comes from

Formed from Latin squama, meaning scale, describing the flattened, scale like appearance of these cells under the microscope.

For learning, not diagnosis. This glossary provides general educational information and is not a substitute for advice from a qualified healthcare professional. If you may be experiencing a medical emergency, contact local emergency services.