What Would You Like to Know about Pathology?

What is Pathology?

Pathology is the branch of science that examines and diagnoses the causes and mechanisms of diseases.

Who is a pathologist?

A Pathologist is a medical doctor who makes a diagnosis by examining tissue and organ samples and fluids taken from your body under a microscope and performing some tests on these samples.

How to Read a Pathology Report of Cancer?

A sample taken from cancerous tissue to diagnose it, is called a biopsy. Biopsies and surgically removed tissues and organs are examined by pathologists. Pathologists are doctors who diagnose cancer by examining the tissues  under a microscope and performing some tests on the tissue.The shape of each pathology report may not be the same, but in general terms a report includes the following parts:

1. Patient information and clinical information and findings: This section contains information such as the patient's name, surname, age, gender, the protocol number defined for the patient, and a summary of the information and findings provided by the clinician.
2. Macroscopic Findings: In this section, the features detected in the material when examined with the naked eye, the dimensions of the material, the diameter and location of the lesions detected, and their distance to the surgical margins are indicated. Again, samples taken for microscopic examination are explained in this section.
3. Microscopic Findings: Details of the examination performed under microscope are explained in this section, if needed.
4. Diagnosis: In this section, pathology diagnoses  are listed. If the tissue is cancerous, the initial diagnosis usually includes the name and type of cancer, and the differentiation degree called "grade". This is followed by the diagnosis of lymph nodes. The number of lymph nodes, which are called 'metastatic' to which cancer has spread, and which are called 'reactive' since it usually includes the response of the tissue to the tumor, is given. If there is a diagnosis of benign changes and diseases observed in the surrounding tissue, it is also stated in this section.
5. Comments / Notes: This section is the area where the pathologist states and emphasizes the data that they think will help  clinical staging of the disease. The diameter of the tumor, whether the surgical margins are involved, whether the tumor has spread into the surrounding blood and lymph vessels, if the lymph nodes have metastasized, the size of the metastasis and whether it is out of the lymph node, if additional tests are performed on the tissue to help your treatment, their results are also included in this part.

What Is Cancer Type? How Is It Determined?

There are hundreds of different types of cancer. The type of cancer is an important factor in both the treatment of the disease and how it will behave. The main method used to determine the type of cancer is examination under a microscope. Many types of cancers can be easily identified under a microscope. But sometimes that may not be enough. Other tests may be required on the tissue to reach a final decision. The most used tests are special staining done by immunohistochemical methods. Sometimes it may be necessary to determine DNA changes in the cancerous tissue to be sure of the cancer type, and the tests performed for this purpose are called molecular tests.

What Does 'Grade' of Cancer Mean?

The 'grade' of the cancer determines the degree of differentiation. It is an important parameter for many cancers to predict treatment and disease behavior. Cancer disease consists of irregular growth of cells that are out of control. The more cancerous tissue mimics the normal structure, the better it is 'differentiated', that is, it is well differentiated. The better the cancer is differentiated, the better it is expected to behave. The ‘grade (histological differentiation) of the cancer is placed by examination under the microscope. It is determined in accordance with the criteria and evaluation system set for each cancer type.

What Does Metastatic Lymph Node Mean?

If cancers are 'invasive', that is, if they have managed to pass into the connective tissue of the organ structures where they first developed, they can spread to more distant organs via blood and lymph vessels located there. This event is called 'metastasis'. Cancers usually first metastasize in regional lymph nodes that filter the lymph fluid of the organ where the cancer originated.
Lymph nodes are popularly known as the gland. They are organs belonging to the body's immune system. In the lymph nodes, the fluid collected by lymph channels from the organs is filtered, and threats such as foreign proteins and microorganisms are determined and the immune system is stimulated accordingly. If cancer cells reach lymph channels and lymph nodes using the same route and settle and occupy the lymph node they reach, this lymph node is called 'metastatic lymph node'.
The number of metastatic lymph nodes, the size of the metastasis, and whether it spreads beyond the lymph node are important criteria for determining the treatment and behavior of the disease and are stated in the pathology report.

What Does Reactive Lymph Node Mean?

They are lymph nodes that do not contain metastases, but only contain findings on the immune system's response to cancer. Their number is also stated in the pathology report.

Does the Size of the Tumor Matter?

For many cancers, the size of the tumor is an important parameter for treatment and follow-up. In every pathology report, especially the size of the invasive part of the tumor should be included.
Tumor size is determined during pathological examination by macroscopic (examination of tissue with naked eye ') and microscopic (examination of samples taken during macroscopic examination under microscope) methods. In some tumors, tumor size is determined only by macroscopy, while some are decided by combining the results of macroscopy and microscopy. This condition is related to the type of cancer.
While some types of cancer are separated from the surrounding tissue with well-demarcated boundaries, others grow by spreading between cells in normal tissue and do not form well-defined masses. The tumor may be larger than radiologically and clinically predicted. Sometimes, most of the mass detected in the patient belongs to the in-situ (grown in normal tissue structures, not yet emerged into the connective tissue of the organ) component of the tumor, and the invasive tumor may be smaller. Or, some of the mass detected may be due to clot and tissue reaction due to previous biopsies. In this case, pathologically detected invasive tumor size may be smaller than the estimates in radiological and clinical examinations.