Why do they study the structure of "diseased" tissues, and why is a second opinion necessary in oncodiagnosis?
Why do they study the structure of "diseased" tissues, and why is a second opinion necessary in oncodiagnosis?
A pathologist explained this

Every year, several million people in Belarus become patients of pathologists, although many of them are not even aware of it. The thing is, according to the legislation, any material taken from a patient must be examined. Analysis includes not only small pieces of the gastric mucosa taken during routine fibrogastroscopy but also fragments of various tumors obtained through biopsy.

Certainly, morphological analysis is particularly significant for people with oncological diseases. It is not surprising that many patients with malignant pathology want to obtain two (or even three) independent conclusions from different medical institutions, says the head of the pathoanatomical department of the RCMC, Pavel Motolyanets.


— Let's clarify some concepts. Are morphological, histological, and cytological studies the same thing? What is referred to as a specimen in pathological anatomy?

—Morphology examines structure. What clinical medicine deals with is called pathomorphology, which is the morphology of diseases. We assess structural changes in the tissues and cells of the human body that underlie diseases.

Histological and cytological studies fall under the category of morphological studies. To put it simply, histology + cytology = morphology.

A cytologist analyzes cells, while a pathologist examines tissues.

The "packaged" slices of tissues taken for morphological examination are called specimens. The analysis of these "slides" is referred to as the consultation of finished histological specimens.


—Where and how is tissue collected for analysis? How is it examined?

— The material is collected by a doctor through puncture, biopsy, or during surgery. For example, an endoscopist conducting an endoscopic examination of the stomach or intestines inspects the mucous membrane and takes small biopsies, which are then evaluated by a pathologist.

I would highlight 2 stages of material examination in the laboratory:

  • macroscopic;
  • microscopic.

Conditionally, one can also add a pre-analytical stage to them — it is the collection of material and preservation: the tissue needs to be properly fixed in formalin.

Then, in the laboratory, the doctor evaluates the material first with the naked eye and describes it in the simplest terms — shape, size, color.

Then, by a certain method, this tissue is processed, embedded in paraffin. Thin sections are prepared on a special device — a microtome. They are stained with special techniques and covered with a special glass.

The microscopic stage of diagnosis begins. We evaluate cells, tissue, features of blood supply, etc. It is necessary to consider all microscopic signs, because based on their combination, like pieces of a puzzle, a diagnosis is formed. Tumors have their own characteristics, inflammatory processes have their own.


— How many 'slides' are usually obtained?

—It can be 4, 12, or 30 pieces, for example.

When examining the stomach mucosa, the endoscopist takes tissue samples from different parts of the stomach, and sometimes from the esophagus. They are always separately marked. Accordingly, these will be separate specimens.

Another example: to identify the causative agent of gastritis - Helicobacter pylori, we must stain it not only with the routine method but also with an additional stain - Romanovsky-Giemsa. It helps identify this particular pathogen. It turns out that the same section is stained with two different methods, so there are more specimens.


— How does morphological examination aid in the diagnosis of diseases?

— Morphological diagnosis is one of the most accurate and objective methods. This is particularly relevant in oncology, as it is crucial to determine the type and differentiation of the tumor, as well as the stage of the disease.

For instance, if a person has gastritis, it could be related to an H. pylori infection, or it could be a specific variant such as autoimmune or lymphocytic gastritis. Sometimes, without immunohistochemistry performed during the consultation of prepared histological specimens, it is impossible to establish the type. By conducting a consultation of specimens and additional staining, we can inform the patient, for example, that they have autoimmune gastritis.


— When might an additional conclusion be needed for already prepared histological specimens?

— One possible scenario is when the primary diagnosis based on a biopsy is conducted at the patient's local facility, but the patient wishes to undergo surgery at a different medical institution. Before this, the specimens need to be reviewed at the new facility so that the surgeons conducting the operation can have a comprehensive understanding of the diagnosis.

Furthermore, when analyzing the surgical material, changes that occurred after the biopsy can be identified. Both the tumor stage and its variant may change. In the first case, only a fragment of the tumor was evaluated, while in the second, the entire tumor is assessed. Naturally, more can be observed in the surgical material.


Another situation arises when a patient simply seeks a second opinion.

The consultation on prepared histological specimens s often initiated by the patient themselves. When it comes not only to health but also to one's life, a person may be inclined to distrust their doctor and harbor doubts. This is completely understandable.

Fortunately, in the overwhelming majority of cases, the second opinion aligns with the views of colleagues who initially examined the material. Pathologists conducting consultations on prepared histological specimens play the role of both diagnosticians and psychologists, aiming to reassure the individual. When a patient hears the same opinion from three different specialists, doubts are significantly reduced.

It is also crucial for the doctor who examined the patient's tissues to personally communicate with them and explain the situation in simple terms. For most people, merely seeing the conclusion in the biopsy report is not sufficient.


— What does a patient need to obtain a conclusion in another medical institution?

— Retrieve their histological specimens (commonly referred to as slides) and paraffin blocks from where they were prepared and take them to the medical institution where the person wants to seek additional consultation.

It is also necessary to bring along medical documentation. Usually, an extract or an epicrisis is sufficient. However, sometimes patients have data from X-ray examinations and laboratory tests. Of course, it would be good for the doctor to review this as well, to have a comprehensive understanding of the patient.

Some may find it useful to know that in pathological anatomy and morphological diagnostics, telemedicine capabilities can be utilized. The specimen (slide) can be converted into a digital format. This substantial image is placed on cloud storage, and the patient is provided with a link to it. They can then send this link for consultation to a medical institution in another city or even country. While this is not widely used in Belarus yet, the possibility exists.


— How reliable is morphological examination? What is the probability of error?

— There is always some likelihood of error, as any doctor is a human being. That's why it's important for the doctor not only to examine the specimen but also to consider the patient as a whole. That's why I suggest that, during a consultation, it's better to bring not only the test results but also additional medical documentation. The diagnosis is not solely based on morphological changes.

The experience and qualifications of the doctor, of course, also play a significant role.


— What else affects the accuracy of the results?

— It is crucial to appropriately obtain histological material for examination. A high-quality specimen must be prepared from it. Quality reagents and reliable equipment are necessary: a microscope for the doctor to examine the material, as well as equipment used for preparing specimens and processing materials in the laboratory.

The examination is not only based on changes observed under a regular light microscope. Additional diagnostic methods are also employed.

It is beneficial if the medical center has the capability to perform immunohistochemical studies. In simple terms, this is when specific proteins in the tissue can be visualized. The combination of these proteins, their presence or absence, leads to a specific diagnosis. For instance, to establish prostate cancer, it is necessary to prove the absence of basal cells in tumor growth areas.

For a patient with breast cancer, according to modern protocols, we must classify the tumor based on its sensitivity to hormonal treatment, Herceptin, and assess its proliferation. In other words, thanks to immunohistochemical studies, it is possible to determine which medications the tumor is sensitive to and which it is not, and convey this information to the oncologist responsible for the patient's treatment.

Immunohistochemical studies represent a more advanced level of diagnostics, a highly technological approach, one might say.


— Is artificial intelligence not yet used for the analysis of ready histological specimens?

— Systems based on neural networks are successfully trained and utilized in cervical cancer screening. Digitized cytological specimens are uploaded into the system, and the algorithm detects dysplasia, cancer, and other processes. However, the areas identified by the system still need to be evaluated by a doctor. The doctor provides the final conclusion on whether it is cancer or not. In other words, artificial intelligence assists, but the ultimate decision remains with the doctor.


— In what cases is a collective review of ready histological specimens conducted?

— Most often, this occurs when the patient has oncological pathology. When there is a small amount of tumor tissue, it is possible to consult with colleagues in the department. Some doctors specialize more in one pathology in their practice, while others focus on different ones. It is always useful to seek their opinion.

— How long can glass and paraffin blocks be stored?

— If the patient does not take them home, they can be stored in the medical facility for decades. And materials from cancer patients can be stored almost indefinitely.

Why? Unfortunately, even after achieving remission, a relapse can occur—after 5, 10 years, or even more. In such cases, one can return to these specimens, retrieve them from the clinic where the research was conducted, review and compare them with new operative material. This will be helpful for the doctor in planning treatment.

The second scenario: if the child or grandchild of the patient develops something similar to what the patient had, comparing their tissues will aid in diagnosis and treatment. It may involve an inherited pathology.

Based on observations, if people do not come for their specimens within a year, two, or three, they usually do not retrieve them at all.

If one wishes to keep specimens and paraffin blocks at home, certain conditions should be observed: it should be a dark, dry, well-ventilated place away from heat.


—In what cases might it be necessary to re-take a sample?

— Most commonly, this pertains to biopsies. This method should be minimally invasive for the patient, so typically, a small piece of tissue is taken. However, due to the technical nuances, sometimes this may not be sufficient for a conclusive diagnosis. Additionally, there may be excess mucus; the needle may pass through a cyst or blood vessel; there might be too few cells or tissues collected... In such instances, a repeat biopsy is performed to establish an accurate diagnosis.


—How long does it take to receive a consultative opinion on ready histological specimens?

— Consultation on ready specimens takes a short amount of time, ranging from a few hours to several days. However, if we are talking about the preparation time for the specimens, it takes longer.

In modern conditions, for biopsy material, when the tissue sample is small, it usually takes 2–3 days from the moment the material is collected to the final report, unless additional investigations are required.

For surgical material, where tissue samples are larger and the volume of examination is greater, it may take up to 5 working days. If additional methods, such as immunohistochemistry, are needed, as mentioned earlier, the investigation may take up to two weeks, but these are rare cases.

According to legislation, any tissue or material taken from a patient must be examined. Few people know this, but in Belarus, several million such examinations are carried out annually. If you have ever had surgery, you almost certainly were indirectly a patient of a pathologist: all tissues removed during surgery are also subject to morphological examination.

A pathologist is a doctor who is usually associated with autopsy (post-mortem examination and study of the body). However, this is no longer the case. Today, our main task is the diagnosis of diseases during a person's lifetime.

Interviewed by: Kristina Holoviyuchuk

Photo: Anna Zankovich