[Medical Science] The mysterious department in the hospital - Pathology Department

1. Why do we need pathology?

As a pathologist, it is necessary to help everyone further understand the pathology department.

Pathology is one of the most important examinations in medical examinations. Pathological diagnosis is regarded as the "gold standard" of diagnosis, and pathologists are called "doctors' doctors."

When patients visit the doctor, they undergo many tests, such as blood tests, ultrasounds, CT scans, etc. However, they only know about the imaging department and the testing department, and are unfamiliar with the pathology department. They often ask why they need to undergo pathology examinations?

Imaging examinations are mostly performed by looking at images for positioning diagnosis; pathology is to take the "flesh" removed from the patient, and make it into a few microns thick pathological slices by pathological technicians through dozens of delicate, professional and tedious steps, and use microscopes to analyze cell morphology for qualitative diagnosis. The main task is to determine the nature of the disease, is it inflammation or tumor? What type of inflammation? Is it a benign tumor or a malignant tumor? Where does the tumor come from? Is it metastatic or primary? How malignant? How deep is the invasion? Is there any cancer remnant at the cutting edge, is there any lymph node metastasis, etc. It can not only determine the nature, severity, spread range, and adequacy of surgery of the disease, but also find suitable targets at the molecular level for accurate diagnosis and treatment.

2. Why are pathology reports slower than other reports?

The specimens handled by the pathology department include various tissue biopsy specimens, resection specimens, various cytology specimens and autopsy specimens, such as gastrointestinal endoscopic biopsy, various tissue punctures, appendix, gallbladder, breast, whole uterus, etc. So what is the workflow of the pathology department? Patients often ask when the report can be issued?

After receiving the specimen, the pathology department will check the information, number, fix the specimen, extract the specimen, dehydrate, embed, slice, stain and seal the specimen. The pathology technician will make pathological sections several microns thick, and the pathologist will make a pathological diagnosis by carefully observing the clues under the microscope.

3. What are the common pathological examinations?

1. Routine histological examination

The principle followed by modern hospitals is that any tissue specimen taken from the patient's body must have a pathological histological examination report. Sometimes when HE sections cannot make a clear judgment, immunohistochemical staining, special staining, in situ hybridization technology and genetic testing are needed to assist in diagnosis. Patients can get a clear diagnosis or provide very useful disease information through pathology.

HE staining

2. Cytological examination

Cytology is mainly divided into gynecological and non-gynecological cytology (such as sputum, cerebrospinal fluid, bronchoalveolar lavage fluid, pleural effusion, etc.), and is divided into puncture cytology, exfoliative cytology, etc. according to the collection method. Compared with histological examination, cytology is less invasive, economical, and fast. Although it looks simpler, it is still very difficult for pathologists.

Liquid-based cervical cytology

3. Intraoperative frozen pathology examination

The most challenging work in the pathology department is intraoperative frozen section pathology diagnosis. The patient lies on the operating table, and the patient's relatives and friends outside the operating room are anxiously waiting. The pathologist must make a clear diagnosis within dozens of minutes. Benign lesions can be removed locally, while malignant lesions require further extended resection or lymph node dissection or removal of important organs. This shows the great pressure and heavy responsibility of pathologists.

Cryostat

4. Immunohistochemistry

Immunohistochemistry (abbreviated as IHC) is the identification of these antigen molecules through the specific binding of antibodies to antigen components in the identified tissues or cells. Immunohistochemistry plays an increasingly important role in the pathological diagnosis of diseases, and many immunohistochemical markers have prognostic significance. For example, HER2 (3+) in breast cancer indicates a poor prognosis of the tumor, and a high Ki-67 labeling rate indicates active proliferation. It is also an important marker for the grading of gastric, intestinal, and pancreatic neuroendocrine tumors.

HER2

5. Molecular pathology examination

Molecular pathology is a new branch of pathology formed by the cross-integration of traditional pathology with molecular biology, biochemistry, proteomics, and genetics. It mainly studies and diagnoses diseases by detecting changes in molecules in organs, tissues, or body fluids. Molecular pathology combines molecular changes with tissue and cell morphology, which not only makes pathological diagnosis more accurate, but can also be used for molecular classification of diseases, evaluation of disease treatment effects and prognosis, and screening of disease-susceptible individuals.

FISH

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