Understanding Your Pathology Report

A pathology report is a document that contains the diagnosis determined by examining cells and tissues under a microscope. The report may also contain information about the size, shape, and appearance of a specimen as it looks to the naked eye. This information is known as the gross description.

 The pathology report may include the following information (1):

• Patient information: Name, birth date, biopsy date.
   
• Gross description: Color, weight, and size of tissue as seen by the naked eye.
   
• Microscopic description: How the sample looks under the microscope and how it compares with normal cells.
   
• Diagnosis: Type of tumor/cancer and grade (how abnormal the cells look under the microscope and how quickly the tumor is likely to grow and spread).
   
• Tumor size: Measured in centimeters.
   
• Tumor margins: There are three possible findings when the biopsy sample is the entire tumor:
  • Positive margins mean that cancer cells are found at the edge of the material removed.
     
  • Negative, not involved, clear, or free margins mean that no cancer cells are found at the outer edge.
     
  • Close margins are neither negative nor positive.
     
• Other information: Usually notes about samples that have been sent for other tests or a second opinion.
   
•  Pathologist’s signature and name and address of the laboratory.

After identifying the tissue as cancerous, the pathologist may perform additional tests to get more information about the tumor that cannot be determined by looking at the tissue with routine stains, such as hematoxylin and eosin (also known as H&E), under a microscope (2). The pathology report will include the results of these tests. For example, the pathology report may include information obtained from immunochemical stains (IHC). IHC uses antibodies to identify specific antigens on the surface of cancer cells. IHC can often be used to:

• Determine where the cancer started.

• Distinguish among different cancer types, such as carcinoma, melanoma, and lymphoma.

• Help diagnose and classify leukemias and lymphomas (3).

The pathology report may also include the results of flow cytometry. Flow cytometry is a method of measuring properties of cells in a sample, including the number of cells, percentage of live cells, cell size and shape, and presence of tumor markers on the cell surface. (Tumor markers are substances produced by tumor cells or by other cells in the body in response to cancer or certain noncancerous conditions.) Flow cytometry can be used in the diagnosis, classification, and management of cancers such as acute leukemia, chronic lymphoproliferative disorders, and non-Hodgkin lymphoma (2).

Finally, the pathology report may include the results of molecular diagnostic and cytogenetic studies. Such studies investigate the presence or absence of malignant cells, and genetic or molecular abnormalities in specimens.

Cytogenetics uses tissue culture and specialized techniques to provide genetic information about cells, particularly genetic alterations. Some genetic alterations are markers or indicators of a specific cancer. For example, the Philadelphia chromosome is associated with chronic myelogenous leukemia (CML). Some alterations can provide information about prognosis, which helps the doctor make treatment recommendations (3). Some tests that might be performed on a tissue sample include:

• Fluorescence in situ hybridization (FISH) determines the positions of particular genes. It can be used to identify chromosomal abnormalities and to map genes.
• Polymerase chain reaction (PCR) is a method of making many copies of particular DNA sequences of relevance to the diagnosis. 
• Real-time PCR or quantitative PCR is a method of measuring how many copies of a particular DNA sequence are present.
• Reverse-transcriptase polymerase chain reaction (RT-PCR) is a method of making many copies of a specific RNA sequence. 
• Southern blot hybridization detects specific DNA fragments. 
• Western blot hybridization identifies and analyzes proteins or peptides.

For more information on pathology reports, see the National Cancer Institute's Fact Sheet.

Selected References

1. Morra M, Potts E. Choices. 4th ed. New York: HarperResource, 2003. 
2. Borowitz M, Westra W, Cooley LD, et al. Pathology and laboratory medicine. In: Abeloff MD, Armitage JO, Niederhuber JE, Kastan MB, McKenna WG, editors. Clinical Oncology. 3rd ed. London: Churchill Livingstone, 2004. 
3.  Connolly JL, Schnitt SJ, Wang HH, et al. Principles of cancer pathology. In: Bast RC Jr., Kufe DW, Pollock RE, et al., editors. Cancer Medicine. 6th ed. Hamilton, Ontario, Canada: BC Decker Inc., 2003.
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