Pathology dictionary

What is a mass?

A mass is abnormal tissue that takes up space in the body as it grows. The mass is usually surrounded by normal tissue.

The abnormal tissue inside a mass can be non-cancerous or cancerous. For this reason, mass is a descriptive word and not a diagnosis. The condition causing the mass can be determined after tissue is sent to a pathologist for examination under a microscope.

Examples of non-cancerous conditions that can cause a mass:

  • Benign tumours.
  • Infections.
  • Immune reaction (such as an allergic reaction).
  • Blood (such as in a large bruise).

Examples of cancers that can cause a mass:

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