What is Histopathology?

Histopathology means using a microscope to look at human tissue to see if it has signs of diseases, damage, or other abnormalities.

Histology is the study of tissues, and pathology is the study of disease. Thus, histopathology means the study of tissues related to disease.

A histopathology report describes the tissue that the pathologist examined. It can identify features of what cancer looks like under the microscope. A histopathology report is also sometimes called a biopsy report or a pathology report.

This article explains the purpose of histopathology, what's in a histopathology report, and reasons why a histopathology test may be done. It also details some of the ways that results are interpreted.

How Is Histopathology Performed?

Histopathology is performed by a specialist doctor, called a pathologist, who examines tissue under a microscope. Pathologists study samples of tissue in a lab.

Pathologists process and cut tissue into very thin layers, called sections. Then, they stain and examine it with a microscope. Using a microscope, they can observe and document the tissue's details.

Identifying Disease

Histopathology relies on samples of tissue obtained through procedures such as endoscopy, colonoscopy, and colposcopy, or by doing surgical procedures such as a breast biopsy.

Diseases that are diagnosed by histopathology examination include:

• Ulcerative colitis
• Crohn's disease
• Uterine fibroids
• Cancer
• Infections

Frozen Section

For some diseases, a sample of the tissue can be interpreted very quickly using frozen sections (also called a cryosection) that are obtained during surgery. Frozen sections are examined immediately in the lab to provide a result within about 20 minutes.

This type of pathology is most commonly used to evaluate tumor margins during surgery so that a surgeon can decide if more tissue should be removed for full removal of cancer.

The use of frozen sections during surgery depends on the type of cancer being removed and other factors.

Lymph and Blood Cancers

Lymph nodes are often biopsied to evaluate for certain types of blood cancer and to identify metastases of solid tumors (such as breast cancer and lung cancer). A bone marrow biopsy may also be required for a definitive diagnosis for many types of blood cancers.​

Components of a Histopathology Report

Histopathology reports on surgical cancer specimens can be complex.

They may include:

• A description of the appearance of the involved tissue
• A diagnosis
• A synoptic report detailing the findings of the case
• Pathologist's comments

Interpreting the Results

Many of the pathologist's findings are used to help determine prognosis, especially in cases of cancer.

Prognostic indicators may include:

• Size and severity of the disease
• Tumor grade
• Indications that cancer has spread and extent of spread

Grading systems differ depending on the kind of cancer. In general, the cells are scored based on how abnormal they appear under the microscope.

For example, Grade 1 tumors appear nearly normal, whereas Grade 4 tumors reflect more abnormalities. The more abnormal the cells look, the higher the grade.

Other Sampling Techniques

In addition to histopathology, pathologists may use other techniques to assess the presence of cancer in the tissues.

Molecular Techniques

Molecular techniques refer to the ability to analyze cells and tissues at the molecular level, which is at the level of proteins, receptors, and genes.

Pathologists diagnose cancer, such as leukemia, through a combination of techniques, including:

• Cytochemistry: How the sampled cells take up certain stains
• Immunophenotype: Looks for unique surface proteins
• Karyotype: Chromosomal changes
• Morphology: How the cells look

Immunohistochemistry

Often in lymphomas and other cancers, doctors use immunohistochemistry to help assess the tumor type, prognosis, and treatment.

For example, if CD23 and CD5 are present in the cancer cells, it might support the notion that chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL) is a possible diagnosis.

However, these same markers are also present in other malignancies. So doctors use this method in combination with other identifying features.

Chromosomal Studies

Pathologists may perform molecular and chromosomal studies to look at gene rearrangements and specific changes to the chromosomes. Sometimes inserted or deleted genes correlate to prognosis. Genetic changes present in a cancer tissue sample may be hereditary or acquired.

For instance, in CLL, a specific piece of a chromosome (17p) is lost. Along with the missing chromosome, a gene that helps suppress cancer is often lost. The 17p deletion is found in about 5% to 10% of people with CLL overall. The 17p deletion CLL is a form of CLL that is harder to treat with conventional chemotherapy.

Summary

Histopathology is the study of tissue to look for disease. Pathologists perform histopathology in a lab. They examine tissue under a microscope and develop a report of their findings.

Histopathology reports can include descriptions of the tissue, diagnosis, and prognosis. In addition to evaluating the shape and structure of cells, pathologists may also use other techniques to assess and diagnose cancer.

A Word From Verywell

It's best to discuss histopathology reports with your healthcare provider rather than trying to interpret them on your own. Your report will contain information about your tissue sample, offer a diagnosis or suggestions for further testing, and help to guide your treatment.