Pathology, also known as surgical pathology, diagnostic pathology and tumor pathology, is a basic medical discipline that studies the etiology, pathogenesis, pathological changes, outcome and prognosis of diseases. It provides a theoretical basis for the diagnosis, treatment and prevention of diseases by revealing their essence and the laws of occurrence and development, and is also a bridging discipline. In the process of clinical diagnosis and treatment, pathology is an important method for diagnosing diseases and providing a basis for treatment. Therefore, it also belongs to the clinical discipline. It not only reveals what the disease is, but also explains why it is.

A disease must have a certain pathological basis. Certain pathological changes will inevitably lead to corresponding clinical symptoms. Pathology is the main qualitative diagnostic method for clinical diseases. American medical experts call pathology "the foundation of medicine", and clinicians refer to it as "medical judges". Therefore, pathology holds an important position in the field of medicine.

The main examination method in pathology is: biopsy, also known as pathological examination. That is, the specimens obtained by commonly used clinical methods such as surgical resection, endoscopic forceps extraction, fine-needle aspiration, scratching and picking are sectioned, observed under a microscope and diagnosed. To determine the nature during the operation, a rapid freezing test can also be performed during the operation. The tissue origin of the tumor can also be further determined through immunohistochemistry.