December 7, 2023


In pathology, the term “mass” is used to describe an abnormal lump or growth in the body. The mass is usually surrounded by normal tissue. Masses can occur for various reasons, and they may be benign (non-cancerous) or malignant (cancerous).

Although the words mass and tumour are often used interchangeably, they typically refer to different things. For example, mass is a more general term that can be applied to any process taking up space in the body. In this way, a hematoma (a large collection of blood) can be described as a mass. In contrast, in modern medicine, the term tumour is used to describe a growth made up of abnormal cells which continue to grow over time.

Types of masses found in the body

Masses caused by non-cancerous conditions:
  • Localized infections
  • Immune reactions (such as an allergic reaction)
  • Blood (such as in a large bruise)
  • Cysts
Masses caused by benign (non-cancerous) tumours:
Masses caused by malignant (cancerous) tumours:

About this article

This article was written by doctors to help you read and understand your pathology report. Contact us if you have questions about this article or your pathology report. For a complete introduction to your pathology report, read this article.

Other helpful resources

Pathology Atlas
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