In pathology, low grade is used to describe cells that look abnormal when examined under the microscope but still share some features with normal, healthy cells. In order to determine if cells are low grade, pathologists often compare the abnormal-looking cells to the cells normally found in that part of the body. The term low grade can be used to describe cells found in both precancerous conditions and cancers. The term low grade is also found in the names of many different types of tumours.
The term low grade is used commonly to describe both cancer and precancerous conditions. Other terms that are often used to describe low grade cancer include carcinoma, adenocarcinoma, and sarcoma. Dysplasia is a precancerous condition that can be described as low grade when the abnormal cells resemble normal, healthy cells and the risk of turning into cancer over time is low.
Low grade is commonly used to describe precancerous cells; however, it can also be used to describe other conditions such as cancerous tumours. In many parts of the body, when low grade is being used to describe a precancerous condition, it is often combined with the term dysplasia. Low grade dysplasia typically involves the cells that cover the outside or inside surface of a tissue and it is commonly seen in the esophagus, stomach, and colon. Other examples of low grade precancerous conditions include low grade squamous intraepithelial lesion (LSIL) and low grade ductal carcinoma in situ (DCIS) of the breast.
Cancer is described as low grade when the cells are abnormal looking, but they still share some features with normal, healthy cells. Low grade cancers typically behave in a less aggressive manner and are more likely to grow more slowly and are less likely to metastasize (spread) to other parts of the body.