Pathology dictionary -
Acute inflammation is the body’s first defense response to injury or disease. The response is led by immune cells such as neutrophils and eosinophils. Some pathology reports will describe acute inflammation as "active" inflammation to emphasize the fact that it is an ongoing process.
Acute inflammation can be associated with infections, traumatic injury, autoimmune disease (such as rheumatoid arthritis), or cancer.
Although acute inflammation is an important part of the body's defense system, prolonged acute inflammation can cause injury to the tissue involved. These kinds of changes are commonly seen in the skin, mouth, and gastrointestinal tract (esophagus, stomach, small bowel, and colon).
Your doctor may remove a small piece of tissue in a procedure called a biopsy and send it to a pathologist to look for acute (active) inflammation. By examining the tissue under a microscope, your pathologist will also be able rule out other conditions that can look like inflammation, such as cancer.