Comprehensive approach to assessing biopsy results
The results of a histological examination of biopsy material are never viewed in isolation by clinicians. To make an accurate diagnosis, they must be evaluated in an inseparable combination with medical history data, as well as the results of physical, laboratory, and instrumental examinations.
In many modern clinical guidelines (e.g., in the diagnosis of pancreatic cancer or renal parenchyma cancer), the definitive diagnosis is established solely based on the aggregate of all listed data. At the same time, it is the pathoanatomical examination of biopsy or surgical material that acts as the crucial morphological component, without which verification of the pathological process is impossible.
Limitations of intraoperative diagnostics
Intraoperative rapid diagnostics occupies a special place in pathological anatomy. However, this method of working with biopsy material has serious limitations. Even when directly in the operating room—during a surgical intervention (laparoscopy or laparotomy)—the specialist cannot always immediately make a final judgment.
A correct diagnosis in certain complex diseases at the rapid biopsy stage can only be achieved in a fraction of cases. This dictates a strict rule: any surgical intervention highlights the absolute necessity of a subsequent, full histological examination of all retrieved surgical material, and if necessary, additional immunohistochemical methods.
Role of immunohistochemistry and phenotype assessment
In modern practice, the method of traditional pathoanatomical examination is regularly supplemented by immunohistochemical examination (IHC). The necessity of using IHC is directly reflected in diagnostic protocols for numerous diseases:
- In breast cancer, the method makes it possible to determine the biological characteristics of the tumor tissue, perform precise staging, and evaluate therapeutic pathomorphosis.
- In gastrointestinal stromal tumors, IHC is required to confirm the diagnosis with mandatory inclusion of specific parameters in the final report.
- In mycosis fungoides, special grading systems are used to standardize pathomorphological reports.
It is important to consider the phenomenon of phenotypic variability. Cases are known in medical practice where a biopsy performed within a very short time interval revealed significant phenotypic differences in various lesion sites in the same patient. If the clinical picture changes, a repeat biopsy may be required.
Mandatory items of the pathomorphological report
To ensure high diagnostic quality (e.g., in patients with germ cell tumors or suspected tumors), both biopsy and surgical material are examined. Drafting the report requires strict standardization and must include the following key parameters:
- Histological structure: description is performed according to the current WHO classification with mandatory indication of the percentage of each identified tumor component.
- Tumor dimensions: exact parameters of the neoplasm.
- pT stage: presence of lymphovascular invasion is evaluated, as well as the depth of spread (e.g., invasion into the rete testis, tunica albuginea, spermatic cord).
- pN stage: indicates the total number of examined lymph nodes, the number of affected nodes, exact dimensions of metastases, and the presence of extranodal extension.
- Resection margin: (e.g., of the spermatic cord)—the physician is obliged to state a negative result, i.e., to confirm the absence of tumor at the cut margin.
- Therapeutic pathomorphosis: evaluated using a specialized TRG scale if the patient previously underwent chemotherapy.
For quick memorization of the mandatory items of an oncological report, use the acronym GRT-NKP (Histology, Size, T-stage, N-stage, Resection margin, Pathomorphosis).
Class and exam questions
Is histological examination the sole criterion for establishing a diagnosis?
No, biopsy results are always evaluated in combination with medical history, laboratory, and instrumental data. However, histology is precisely the crucial morphological component.
Can a definitive diagnosis be made solely based on an intraoperative rapid biopsy?
No, intraoperative diagnostics has limitations. During surgical intervention, an accurate diagnosis is established only in a fraction of cases, which is why a subsequent full routine histological examination is always required.
What must necessarily be reflected in the report when assessing lymph nodes (pN stage)?
It is necessary to indicate the total number of examined and affected lymph nodes, exact metastasis dimensions, and the presence or absence of extranodal tumor extension.
How is the impact of prior treatment on tumor tissue accounted for?
If the patient previously underwent chemotherapy, the physician evaluates the degree of tissue changes—therapeutic pathomorphosis (e.g., according to the TRG scale), which is mandatory to include in the final report.
What else to study on this topic
- Technique of laboratory processing of the biopsy specimen: fixation, tissue processing, and paraffin embedding.
- Microscopic slide staining methods: hematoxylin-eosin and additional stains.
- Organization of the pathological anatomy service and legal aspects of working with material.
- TRG scale: principles and criteria for evaluating therapeutic pathomorphosis.
- Grading systems in mycosis fungoides.
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