Histology, or the study of cells in tissue, is used to diagnose mesothelioma. It is closely related to pathology and how a disease develops in a patient’s tissue. This practice is essential in determining a patient’s diagnosis.
After a doctor takes a tissue biopsy, a pathology report is needed to declare a definitive mesothelioma diagnosis. Pathology reports are the results of lab tests used to detect mesothelioma in tissue samples under a microscope. These tests are the most important factor in determining a patient’s diagnosis, as well as classifying the histology of their disease.
Importance of Histology
Histopathology reports from a biopsy are the only way to definitively determine if a patient has mesothelioma. These reports are essential to determining the mesothelioma cell type (epithelioid, sarcomatoid or biphasic).
By knowing the cell type of the disease, doctors are able to make the most informed decisions about treatment, which ensures the most effective options possible.
Histology is also essential in giving a patient an accurate prognosis. After completing a biopsy, a specialist can make a more definitive diagnosis and give a patient a clear understanding of their life expectancy.
What is Histopathology?
Histopathology is the study of disease in tissue samples at the cellular level. It is the intersection of histology (the study of tissue) and pathology (the study of the causes of disease). Without histopathology, doctors would not be able to learn more about the underlying functions of a disease like mesothelioma. It also would be far more difficult to diagnose, and therefore treat, without such reports on hand.
Difficulties in Diagnosing Mesothelioma
The latency period and symptoms associated with mesothelioma are two factors that account for the difficulty in diagnosing the disease. However, pathologists, who make the final judgment call on diagnosis, run into a different set of issues. Mesothelioma is hard to diagnose for several reasons:
- 1Mesothelioma mimics other diseases
- 2There are various cell types of mesothelioma
- 3Doctors must differentiate between mesothelioma and adenocarcinoma
Misdiagnoses are common since this particular type of cancer is so aggressive and can mimic the symptoms of many other illnesses. It is also due to a large number of pathologists who have never seen malignant mesothelioma cells under a microscope and therefore can mistakenly attribute their cause to other types of cancer. Epithelioid mesothelioma is sometimes misdiagnosed as more common carcinomas, and peritoneal mesothelioma has even been misdiagnosed as ovarian cancer.
Since imaging scans and early diagnostic methods are only useful in determining abnormalities, tissue examinations are necessary to make a clear diagnosis. Under the microscope, pathologists can examine the characteristics of a sample’s histology and determine if it is in fact mesothelioma.
In determining cell type, a pathologist looks for:
- Cellular behavior
- Cell size and shape
- Cell nuclei
- Cell pattern of the sample
Pathologists face certain difficulties when studying mesothelioma samples. The most obvious being the different types of cells that can develop into mesothelioma. Epithelioid cells appear well-defined with visible nuclei, which clump together and can grow localized tumors very quickly. The sarcomatoid cells are more difficult to identify because they resemble benign tissue and are usually spread out on the pleura, which makes them more likely to metastasize.
Inflammation in the lining of the chest or abdomen can create histological changes in the tissue samples taken by a pathologist. This causes cells to move around and look slightly different than other samples, which can lead to missing the mesothelioma cells altogether.
An example of this histological change can be explained by chest infections. The infection must be fought off by the body in order to reduce the number of additional cells present in a tissue sample.
A word commonly seen in the field of pathology is “immunohistochemistry.” This is another method of examining mesothelioma tissue samples by introducing a foreign substance to the sample and then examining the results. In this case, antibodies are introduced that react with mesothelioma cells.
There isn’t a particular antibody that presents a positive stain for mesothelioma, so pathologists have to conduct multiple tests with various antibodies. Antibodies are a part of the immune system (hence the “immuno” in “immunohistochemistry”) that identify foreign invaders like bacteria and viruses.
The stains used to test mesothelioma cells are made up of a combination of antibodies that are used to detect the presence of proteins found in malignant cells. By examining the reaction of these proteins to certain antibodies, doctors are able to identify whether the patient is suffering from mesothelioma or another type of cancer.
The most common positive stains for mesothelioma pathology reports include:
- 1Cytokeratin 5/6
Histology Misdiagnosis and Second Opinions
All the difficulties associated with the histological diagnosis of mesothelioma contribute to a possible misdiagnosis. Since this is a rare form of cancer, many pathologists have never seen these cells under a microscope and therefore are unable to provide an accurate diagnosis. When tests come back as being “inconclusive” or “suspecting” then it becomes necessary for another experienced pathologist to take a look at the results because something may have been missed in the initial analysis.
This makes second opinions essential for all patients diagnosed with mesothelioma before they receive any treatment. The best way for you, as a patient, to ensure an accurate diagnosis is to see an experienced mesothelioma specialist. Connect with top specialists across the country to get your second opinion.