The importance of pathologic diagnosis is well known, and is even known as the “gold standard”. A correct pathological diagnosis is indeed important for the final establishment of clinical diagnosis, and helps clinical formulation of treatment plans and prognosis: planned regular biopsies can help clinical understanding of the dynamic changes of disease development and judging the efficacy of treatment. However, there are limitations in pathological diagnosis, which can be summarized as follows: 1, only for the diagnosis of diseases with morphological changes, for functional or metabolic diseases without morphological changes, pathological examination is meaningless, which is essentially a manifestation of inconsistency between morphological changes and functional and metabolic changes in certain diseases. 2, only reflect the pathological changes at a certain stage in the development of a disease, the development of most diseases has a multi-stage, some diseases only at a certain stage to show characteristic changes, such as intestinal Crohn’s disease only when there are typical fissure-like ulcers and granulomatous changes, to make an accurate pathological diagnosis, mycosis fungoides pre-microscopic changes are non-diagnostic, only when it evolves to the mass stage, seen in the dermis The pathological diagnosis is possible only when it evolves to the mass stage, when heterogeneous lymphocytes are seen in the dermis and when Pautrier abscesses are seen in the epidermis. In addition, morphologic changes have a “lag”: for example, in myocardial infarction, it usually takes 4 h to see the nuclear changes and 6 h to recognize the infarcted foci with the naked eye. If the lesion in the sample is in a non-characteristic phase, it can lead to “missed diagnosis”. 3. Only partially reflect the lesion of the sample sent for examination. Improper sampling (e.g., paracancerous or non-cancerous areas or non-lesioned areas) may also lead to “missed diagnosis” or “misdiagnosis”. 4. It only reflects the depth of knowledge and diagnostic criteria of a disease (type) at the time of diagnosis, with obvious signs of the times (sometimes only a few years to a dozen years apart). As the understanding of the disease deepens and the diagnostic criteria change, the reliability and accuracy of the original diagnosis will change. In fact, the emergence of a new disease (or subtype) is often a revision, deepening, or even denial of the previous understanding, and each revision of the WHO histological typing of tumors is a supplement, revision, or partial denial of the previous version. The essence of this phenomenon is the relationship between relative truth and absolute truth, which should neither be judged by the past nor the present by the present. 5, it is to a considerable extent influenced by the basic knowledge of pathologists, film reading experience and logical thinking, with subjective and empirical. This influence is most prominent in the judgment of some junctional lesions. In this case, the uncertainty of lesion morphology (gray areas), the artificial arbitrariness of diagnostic criteria, and the subjectivity of the observer in the process of image recognition and judgment will inevitably lead to different conclusions from one section by different expert consultations. It is not uncommon to see several diagnoses on a single section by different experts. 6. New technologies and methods are not popular enough, so some cases that could have been diagnosed by immunohistochemistry, electron microscopy, cytogenetics and molecular pathology techniques cannot be diagnosed with the help of new technologies and methods. Some diseases in pathology have common or similar morphology (i.e. “homomorphic heteropathy”), such as round cell tumor, spindle cell tumor, and pleomorphic cell tumor, which are actually not the same independent disease, but they are indistinguishable on HE sections because of their “homomorphism”. They are actually not the same independent disease, but they are indistinguishable in HE sections due to “isomorphism”, and can only be further clarified by the above mentioned technical means. If the pathology department is poorly equipped, the limitations of its diagnosis are bound to be more prominent. This is essentially a reflection of the gap between obsolete equipment and advanced understanding. The above limitations can be reduced through subjective and objective efforts, but it is not objective to make it disappear completely. Both clinical and pathological parties should be highly alert to this.