What does the pathology department do? If you ask ten ordinary people, almost none of them know. Occasionally, a few might have some vague idea, which is already quite rare. Some think pathology is about basic research, some confuse it with the medical records department, and others mix it up with the laboratory department, believing pathology is about conducting tests.
Actually, that’s not the case. The laboratory department does not directly provide diagnostic results for diseases, while the pathology department’s results are the final diagnosis—often referred to as the gold standard. If a clinician says it’s not cancer, but the pathologist says it is, or if the clinician says it’s malignant, but the pathologist says it’s not malignant enough, the pathologist’s opinion must be taken into account. Of course, some diseases require comprehensive consideration combining clinical, pathological, and other examinations. Additionally, for diseases with malignant potential, time is the ultimate test of their benign or malignant nature. In the West, pathologists are called ‘doctors’ doctors,’ some refer to pathology as the foundation of medicine, and others call pathologists the ‘judges’ in the hospital. Chinese respiratory expert Academician Zhong Nanshan once said, ‘The level of pathology is a measure of the medical quality of a country and a hospital.’
Do ordinary people know about pathologists?
In comprehensive hospitals like municipal people’s hospitals, there are numerous departments—currently as many as 48 specialties. Patients sometimes feel lost in the hospital, unsure which department to go to or which doctor to see. Since pathologists do not directly interact with patients and have little contact with them, most ordinary people know very little about these ‘judges’ in the hospital. It’s common for patients to come to the pathology department to request copies of their medical records, or for those needing blood tests to come to the pathology department for laboratory examinations.
In recent years, with the approval of cervical cancer vaccines by the National Medical Products Administration for use in China, the prevention, diagnosis, and treatment of cervical cancer have become widely known to the public. Gradually, ordinary people have started to hear a bit about the pathology department, which is responsible for diagnosing and screening cervical cancer. The main task of pathology is to determine the nature of a disease—whether it is inflammatory or neoplastic, what type of inflammation it is, whether it is a benign tumor, borderline tumor, or malignant tumor, the origin of the tumor, its degree of malignancy, whether there is lymph node metastasis, and so on.
So, what are the daily tasks of the pathology department?
Pathological diagnosis includes several major categories: histopathology, cytopathology, molecular pathology, etc. After receiving specimens, the pathology department goes through dozens of complex and tedious steps to produce pathological slices a few micrometers thick. The process includes receiving and checking specimens, gross examination and sampling, tissue processing (fixation, dehydration), paraffin embedding, sectioning, slide preparation, routine staining (HE staining), mounting with neutral balsam, and finally, pathologists examining the slides under a microscope to make a diagnosis. For difficult cases, department physicians review the slides together.
Most routine work in pathology departments includes: routine pathological examinations, such as biopsy specimens from needle aspiration, gastroscopy, bronchoscopy, and surgical specimens. Cytological examinations: including cervical cytology smears or liquid-based cytology, sputum smears, pleural and ascitic fluid, various fine-needle aspiration smears, etc. However, cytology can only observe changes in human cells and cannot examine the entire morphology of the disease, so its diagnostic value is somewhat limited. Intraoperative frozen section examination: Using freezing methods at temperatures below -20°C to produce sections, intraoperative rapid pathological reports can be issued within 30 minutes. This is mainly used for rapid diagnostic reference during surgery, providing timely and reliable guidance for decisions such as whether to extend surgical resection. It is highly valued by surgeons and patients, but due to limitations in sampling and slide preparation, intraoperative frozen sections have significant diagnostic constraints, with an accuracy rate of about 95%. Immunohistochemical examination: Used to assist in disease diagnosis and differential diagnosis, determine the tissue type and origin of certain malignant tumors, and provide precise, personalized treatment for some tumors. For example, the treatment of breast cancer, which is highly prevalent in women, largely depends on immunohistochemical results. Special staining examinations: Such as acid-fast staining, which is fundamental for diagnosing tuberculosis. Molecular pathology examinations: Precision treatment relies on precise diagnosis. The emergence of molecular pathology has been a boon for cancer patients. Targeted treatment based on detecting various genetic changes in the human body is highly effective. Currently, targeted drugs for lung adenocarcinoma and breast cancer are widely used, offering hope for long-term tumor control and significantly extending patients’ lifespan and quality of life.
Why does it take so long to get a pathology report?
Since specimen processing involves dozens of steps, the processing time for pathological specimens is relatively long. Tissue specimen pathological diagnosis typically takes about 3 working days. Certain special circumstances, such as re-sectioning, deeper sectioning, additional sampling, or re-preparation of slides, may extend the time by several working days. Immunohistochemistry, molecular pathology, special staining, or difficult cases generally require an additional 3 working days on average. Bone tissue or specimens requiring decalcification may take more than 2 additional working days.。
Pathology Department Process and Role
The reports issued by the pathology department are direct diagnostic results. Pathologists perform gross examination, sampling, fixation, dehydration, embedding, sectioning, and staining on biopsy or surgical specimens to produce pathological slides. They then examine the tissue structure and cellular changes under a microscope and, if necessary, conduct auxiliary tests (such as immunohistochemistry or molecular pathology). Combining this with clinical and imaging data, they ultimately make a disease diagnosis. Pathological diagnosis is experience-based, and its accuracy is related to the pathologist’s experience and technical skill. The main task of the pathology department is to determine the nature of a disease—whether it is inflammatory or neoplastic, what tissue type it is, what kind of inflammation it is, whether it is a benign tumor, borderline tumor, or malignant tumor, the origin of the tumor, its degree of malignancy, whether there is lymph node metastasis, and so on.
Which type of specimen provides the most complete and reliable pathology report?
Patients often ask pathologists this question after receiving a biopsy pathology report: ‘Doctor, is my cancer early or late stage?’ This puts pathologists in a difficult position because tumor staging cannot be determined solely from biopsy specimens such as gastroscopy biopsies, needle aspiration biopsies, or bronchoscopy biopsies. Moreover, tumor cells exhibit significant heterogeneity—simply put, variability. In a malignant tumor, one area may be well-differentiated, while another may be poorly differentiated or even dedifferentiated. Tumor staging requires analysis of the entire surgically resected gross specimen and must be evaluated by clinicians in conjunction with other examinations.
Can pathological diagnosis solve all problems?
Currently, pathological diagnosis is widely recognized as the gold standard. However, diseases are ever-changing. The same tumor can exhibit typical changes or atypical ones. I recall a 25-year-old young patient who had a mass in the nasal cavity. After the ENT surgeon removed the mass and sent it for pathological examination, the diagnosis was a low-grade malignant soft tissue tumor due to the rarity of the lesion. Our department’s pathology report suggested consultation with a higher-level hospital for a specific tumor type. The patient visited major hospitals in Shanghai, but the consultation results still indicated a low-grade malignant soft tissue tumor, with the specific type remaining unclear. This shows that even the gold standard can sometimes fail to provide a definitive diagnosis.
Why are pathology archives kept for so long?
Pathology archives typically include pathological slides and tissue paraffin blocks, which are preserved for 15 to 30 years. Preserving specimens ensures follow-up treatment for patients and allows observation of disease progression. They can also be used for disease research, such as providing a basis for treating recurrence or metastasis in malignant tumor patients or for follow-up of borderline tumors.
Author: Zhang Xiaowei, Pathology Department, Dongyang People’s Hospital
