2008 Published in Health News Pathological diagnosis is a diagnosis of a patient’s disease made by a pathologist by combining clinical information (medical history, physical examination, laboratory findings, imaging features, etc.), the general morphology and microscopic features of the tissue submitted for examination, and certain technical means (histochemistry, immunohistochemistry, molecular biology techniques, etc.). This diagnosis is an important basis for clinicians to develop treatment plans and is considered the gold standard. In the current medical situation, accurate pathological diagnosis is particularly important, and it has also gained the attention of hospital management and relevant business departments, and pathological diagnosis has become an important part of clinical medical quality control. Indeed, in modern medicine, the accuracy rate of pathological diagnosis should generally be above 98% to 99%. In other words, the pathological diagnosis of the vast majority of cases in daily work should be correct and can be considered as the gold standard for disease diagnosis. However, for a very small number of difficult cases, this is not the case. Not only pathologists but also relevant clinical specialists should be aware of the limitations of pathological diagnosis at this time. It is these cases that are prone to clinical misdiagnosis, missed diagnosis, and medical disputes, and how to handle such cases deserves attention. Histological features are an important basis for determining the nature of lesions, and their importance is self-evident. We should also see that the rapid development of modern imaging techniques and laboratory tests in recent decades has provided a large amount of biomedical information related to disease, which has greatly facilitated clinical detection and diagnosis of disease. Pathologists who are not aware of this relevant clinical information when making a diagnosis lose an important support point for pathological diagnosis. However, a leading international professor of pathology once noted, “Because of certain 19th century tenets and the habit of scheduling the teaching of pathology in the preclinical phase, there is an incredible misconception among clinicians that if a small piece of a patient’s tissue is given to a pathologist, the pathologist can make an absolutely correct diagnosis at the end of his or her report. If a pathologist held the same view, it would be a great danger to humanity.” In the workplace, it has also been seen that a small number of pathology examination request forms are filled out with important clinical histories, important signs and imaging findings omitted, and the pathologist takes a lot of detours in making the diagnosis. From the perspective of recognition, the essence of pathological diagnosis is the reflection of the human brain to the objective reality (disease), which is a subjective recognition. Therefore, it is inevitable that there will be some deviation between subjective perception and objective reality. Pathologists are also human beings and are subject to the influence of subjective assumptions just like other clinical professionals. Although the systematic study of medical knowledge, training of specialists, implementation of the three-level clinical examination system, and application of new technologies have ensured the accuracy of pathological diagnosis and effectively reduced such bias, it must be admitted that, due to the interference of various factors (limitations in obtaining materials, different stages of lesion development, limitations in the level of understanding, etc.), there are very few difficult cases due to the atypical nature of their lesions. Due to the atypical nature of the lesions, their nature is not well understood at present, and the diagnostic opinions are often widely divergent even after consultation with several large hospitals. The uncertainty of pathological diagnosis at this point means that the gold standard is only relative. In this case, where is the gold standard? It seems that the correct reflection of the subjective consciousness to the objective reality can still only go back to the source of knowledge – the objective disease itself. The so-called gold standard (objectively correct diagnosis) can only be established on the basis of full communication with the clinic and understanding of the patient and the evolution of his lesions. The “gold” is actually in the patient or the disease itself. Therefore, “follow-up is absolutely necessary for patients for whom a diagnosis has not been established.” As pathologists, they are also very happy to know the different opinions of clinicians regarding the initial pathological diagnosis, the subsequent changes in the patient’s condition and the results of the patient’s experimental treatment, and other important clinical information that will facilitate the establishment of the final correct diagnosis – the gold standard. Only in this way can we ensure that patients receive high quality medical care. The author once heard a lecture that ended with the presenter, dermatopathologist A.B. Ackerman, telling of a dream he had. He dreamed at night that the tissue section on the microscope carrier table spoke, and it said, “During the day you people say I am this disease and that person says I am that disease, but in fact, I am me.” I think this is probably the best explanation of the gold standard for disease diagnosis.