The importance of dermatopathological diagnosis There is a wide variety of dermatological diseases, with a total of about 1000 types of dermatological diseases, which is the largest number of diseases among all medical subspecialties. In order to get a good treatment result for any disease, the first choice is to have a clear diagnosis, and dermatology is no exception. Many people think that dermatological diseases are difficult to treat, but the fact that they are not diagnosed is one of the reasons why they cannot be treated in a targeted manner. Since skin diseases occur on the surface of the body, the observation of skin damage is the main means of diagnosing skin diseases. In the past, this observation was mainly done by the naked eye and by observing the skin surface rash with certain auxiliary methods (e.g., magnifying glass, etc.), which is a unique diagnostic method for dermatology and occupies an important position. However, with the advancement of pathology, skin pathology examination by further observation of subsurface skin tissue changes with a microscope is also commonly used in dermatology clinics and has become one of the most valuable methods for dermatological diagnosis. There is a modern saying in the dermatology community that a dermatologist who does not understand skin pathology can only be considered half a dermatologist, illustrating the importance of skin pathology for the correct diagnosis of skin diseases. What skin diseases require dermatopathology? For most diseases, it is difficult to get an accurate and reliable diagnosis simply by visual observation. For example, lichen planus is the most common disease in dermatology with a high incidence, but some atypical lichen planus is difficult to distinguish from neurodermatitis, chronic eczema, itchy rash, and amyloidosis of the skin with the naked eye, but the disease is pathologically characteristic and does not present diagnostic difficulties. Another example is that both aspergillosis and aspergillosis look like blisters and macules to the naked eye, but it is not completely certain which disease it is, and there are still great differences in the treatment of these two diseases, and a clear diagnosis or not directly affects the control and prognosis of the disease. Theoretically, all diseases require a pathological diagnosis in order to reach an industry-accepted diagnosis, and only with histopathology does the diagnosis have accuracy and reliability. Generally, skin pathology is essential in the following cases: 1. skin tumors and precancerous lesions, especially malignant tumors and tumors suspected to have a tendency to recur after treatment. 2, leprosy and skin tuberculosis and other granulomatous diseases For different types of leprosy and skin tuberculosis, it is of considerable value in diagnosis, classification, prognosis and efficacy observation. 3, herpetic dermatoses and vasculitis histopathological examination helps to diagnose and classify. 4.Some skin diseases with pathogens such as various deep fungal diseases, cutaneous black fever, porcine cysticercosis, etc. can be clearly diagnosed by histopathological examination to find the pathogens. 5, skin diseases with relatively specific tissue changes such as connective tissue disease, chronic atrophic limb dermatitis, skin amyloidosis, radiation dermatitis histopathological examination can assist in clinical diagnosis. 6, certain skin diseases with certain specific lesions such as psoriasis, lichen planus, etc. 7, certain diseases with unknown clinical diagnosis Skin diseases with unclear etiology can be examined histopathologically, which can sometimes provide diagnostic clues or can provide the etiology of certain diseases. The steps of skin pathology examination: 1. The ring drill method: Use the appropriate size of the ring drill to remove all or part of the diseased tissue, you can choose from 1.5mm-9mm different caliber ring drill as needed. This method causes minimal damage, heals quickly, and basically does not affect life and work. Some smaller lesions can be removed directly by this method, such as facial pigmented nevi, and the traces left after healing are very small and can achieve cosmetic effects. Excision method: It is to use a scalpel to cut all or part of the diseased tissue. 2.Processing and production of pathological specimens: The lesion tissue is fixed, dehydrated and embedded, and finally cut into thin slices with a microtome, and then stained to make paraffin sections for further observation of the tissue under a microscope. 3.Pathological diagnosis: After the doctor observes and analyzes the sections, the diagnosis is made. Some diseases can be diagnosed based on the sections alone, while some diseases need to be diagnosed by combining visual observation, and others need to be diagnosed by combining various laboratory and imaging examinations.