October 27, 2023
In pathology, the term ‘reactive changes’ is used to describe cells or tissues that look abnormal as a result of alterations in their environment. These changes can include infection, physical injury, medication, and inflammation. By definition, these changes are benign (non-cancerous) in nature.
Anything that alters the environment of a tissue can cause the cells in the tissue to show reactive changes. Common causes include inflammation, viral or bacterial infections, medications/drugs, physical trauma/stress on a tissue, and radiation. Reactive changes can also be seen in the tissues surrounding a tumour.
Pathologists use the term ‘favour’ when the features seen under a microscope are most likely reactive but when other types of changes cannot be completely excluded. For example, in some situations, it can be difficult for a pathologist to tell the difference between reactive changes and a precancerous growth called dysplasia. This is because both of these two conditions share many microscopic features. In this situation, ‘favour’ would be used to show that there was some uncertainty with the diagnosis and that further diagnostic tests may be necessary.
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.