Pathology Reports

A pathology report (sometimes called a surgical pathology report) is a medical report that describes the characteristics of a tissue specimen that is taken from a patient. The pathology report is written by a pathologist, a doctor who has special training in identifying diseases by studying cells and tissues under a microscope.

A pathology report includes identifying information (such as the patient’s name, birthdate, and biopsy date) and details about where in the body the specimen is from and how it was obtained. It typically includes a gross description (a visual description of the specimen as seen by the naked eye), a microscopic description, and a final diagnosis. It may also include a section for comments by the pathologist. 

The pathology report provides the definitive cancer diagnosis. It is also used for staging (describing the extent of cancer within the body, especially whether it has spread) and to help plan treatment.

Common terms that may appear on a cancer pathology report include:

• invasive
• noninvasive
• in situ
• carcinoma
• benign
• neoplasm
• malignant
• adenocarcinoma
• margin
• infiltrating
• ductal
• undifferentiated
• well-differentiated 

The pathologist examines cells or tissues obtained during a biopsy (which is a procedure to remove a cell or tissue specimen for examination by a pathologist) or surgery or from bodily fluids.

A biopsy specimen can be obtained in several ways, such as by 

• taking a tissue sample from the surface of the skin
• using a needle inserted through the skin to withdraw tissue or fluid
• inserting a thin, lighted tube called an endoscope through the mouth, anus, urethra, or a small incision in the skin to look at areas inside the body and remove a sample using special tools that pass through the tube

If surgery is used to remove part or all of a tumor, some or all of the removed tumor specimen will be examined by the pathologist. If the entire tumor is removed, typically the surgeon will attempt to remove some normal tissue around the tumor (known as the margin) for examination by the pathologist to make sure that it doesn’t contain tumor cells. 

For some cancer types, especially breast cancer and melanoma, the surgeon may also remove nearby lymph nodes, called the sentinel lymph nodes, so the pathologist can see if these contain cancer cells. The Sentinel Lymph Node Biopsy fact sheet describes this procedure and its use in determining the extent, or stage, of cancer in the body.

A pathologist may also examine cells that are present in bodily fluids, such as urine, cerebrospinal fluid (the fluid around the brain and spinal cord), sputum (mucus from the lungs), peritoneal (abdominal cavity) fluid, pleural (chest cavity) fluid, cervical/vaginal smears, and bone marrow.

The gross description includes the color, weight, and size of a tissue sample as seen by the naked eye. It may also include the shape of the tissue sample and any visible abnormalities. And it will indicate the body site from where the tissue was taken from, how many samples were taken, and whether and how many lymph nodes were removed.

The microscopic description in a pathology report includes information about the appearance of the cells after they have been stained with routine stains such as hematoxylin and eosin (also known as H&E) and viewed under the microscope. H&E staining helps identify different types of cells and tissues and provides important information about the pattern and shape of cells and the structure of the tissue. With H&E staining, hematoxylin shows the ribosomes, chromatin (genetic material) within the nucleus, and some other structures in the nucleus as a deep blue-purple color. Eosin shows the cytoplasm, collagen, connective tissue, and other structures that surround and support the cell as an orange-pink-red color.

This description may also include the type and number of cells seen in the tissue sample, how abnormal the cells look (also called the tumor grade), and whether there are notable cell features (such as their arrangement and behavior).

The microscopic description section will also indicate whether abnormal cells are found in the margins (the edges of the tissue that has been removed by surgery) or in lymph nodes. Margins are described as negative (or “clean”) when the pathologist finds no cancer cells at the edge of the tissue, suggesting that all of the cancer has been removed. A margin is described as positive (or “involved”) when the pathologist finds cancer cells at the edge of the tissue, suggesting that some of the cancer has not been removed. Lymph nodes are called positive if they have cancer cells and negative if they do not. 

This description may also include the results of additional tests that were performed on the tissue. Depending on the cancer type, these may include tests that

• measure the properties of cells in a sample, including the number of cells, percentage of live cells, cell size and shape, and the proportion of cells that have a tumor marker on their cell surface. See NCI’s Tumor Markers fact sheet for more information about tumor markers and how they are used in cancer diagnosis and treatment. 
• investigate genetic or molecular abnormalities in specimens with the use of specific techniques. These include karyotyping, to detect aneuploidy (abnormal numbers of chromosomes) and large translocations (in which long pieces of chromosomes have broken off and moved to other chromosomes), as well as fluorescence in situ hybridization, to detect specific chromosomal deletions or translocations.

The diagnosis section of a pathology report is the pathologist’s summary of all the findings of their visual and microscopic examination of the tissue specimen, in combination with relevant clinical information. It is in this section that the cancer type will be identified, including the tumor grade, lymph node status, margin status, and stage.

Certain molecular tests, sometimes called biomarker tests, are done as part of the initial pathology analysis for all cases of a given cancer type. For example, a pathology report for a patient with suspected breast cancer will include the results of testing for estrogen and progesterone receptors and the protein HER2/neu. The results of these tests can help identify what treatments are best for an individual patient.

A liquid biopsy—in which a sample of blood or other body fluid is tested to look for pieces of DNA that have been released from tumor cells—is another way that the molecular characteristics of a tumor may be analyzed. The findings of these additional tests may be provided in separate reports that are linked to the pathology report. 

Pathology examination is increasingly incorporating analyses of the structure and sequence of DNA extracted from fresh and fixed tissue samples to refine the cancer diagnosis through improved subtyping and stratification of tumor types and to better inform treatment.