Summary

• If you’ve had a biopsy, surgery or another procedure where tissue is removed, your doctor may send samples to the laboratory for examination to help find out the cause of your illness.

What is anatomical pathology?

Anatomical pathology is the study of body tissues, organs and cells. Anatomical pathologists are specialist doctors who examine under a microscope sample taken from the body, to identify diseases such as cancer, infections and inflammatory conditions.

How does it work?

At the laboratory, an anatomical pathologist will carefully examine your samples. This process may include:

• Looking at the tissue with the naked eye (described on the report as macroscopic examination) to assess its size, shape and appearance
• Preparing thin slices of the tissue and staining them with special dyes
• Examining the tissue under a microscope to look for abnormal cells or disease
• Sometimes using special tests, such as molecular testing or immunohistochemistry, to gather more detailed information
  

Why is it important?

Anatomical pathology plays a key role in diagnosing many conditions. For example, if a lump is removed, an anatomical pathologist can find out whether it is benign (non-cancerous) or malignant (cancerous). After examination, they will prepare a report for your doctor. Their findings help:

• Confirm a diagnosis
• Decide on the best treatment
• Predict how a disease may behave (prognosis)
• Monitor whether treatment is working

Anatomical pathology and cancer
One of the most important roles of anatomical pathology is cancer diagnosis. If cancer is found, the pathologist’s report often includes details such as:

• The type of cancer
• How aggressive it appears
• Whether it has spread into surrounding tissue or lymph nodes (metastasis)
• Whether all the cancer was removed during surgery

This information helps guide treatment decisions such as surgery, chemotherapy or radiation therapy.

Common anatomical pathology tests

Here are the most common tests performed in anatomical pathology:

Biopsy

A biopsy is a procedure where a small sample of tissue is taken from the body so it can be examined under a microscope. This is the most common and important test for diagnosing cancer, but it's also used to diagnose inflammatory conditions, infections and many other non-cancerous diseases.

• How it works: The sample of tissue is chemically preserved, embedded in a wax block, sliced into extremely thin sections, stained with special dyes (most commonly Hematoxylin and Eosin, or H&E) and then examined by a pathologist under a microscope.
• What it tells us: Whether the cells are normal, benign (non-cancerous), pre-cancerous or malignant (cancerous).

Fine Needle Aspiration (FNA) cytology
Cytology is the examination of individual cells, rather than a whole piece of tissue. FNA is a minimally invasive procedure often used to investigate lumps, especially in the thyroid, breast or lymph nodes.

• How it works: A very fine, thin needle is used to draw out a sample of cells or fluid from the lump. The cells are smeared onto a glass slide, stained and examined.
• What it tells us: Whether the mass is a fluid-filled cyst, a benign growth or contains malignant cells.

Surgical resection specimen

When a surgeon removes an organ or a large tumour (resection), the entire specimen is sent to the pathology lab.

• How it works: A specialist scientist carefully examines the specimen macroscopically (with the naked eye), takes multiple small tissue samples from different areas — especially the edges (margins) to ensure the tumour was completely removed — and processes them into slides for microscopic examination.
• What it tells us: Confirms the final diagnosis, determines the grade (how aggressive the tumour looks), the stage (how far it has spread) and, most importantly, verifies if the surgical margins are clear of cancer cells. Clear margins means that when a lump, tumour or other abnormal tissue is removed, no abnormal cells are seen at the outer edges (margins) of the tissue when examined under the microscope. This suggests that all the abnormal tissue was removed during surgery. If cancer cells are found right at the edge it could mean that some abnormal tissue remains.

Advanced techniques in pathology

In addition to standard H&E staining, modern pathology utilises powerful tools to get more detailed information:

• Immunohistochemistry (IHC): This technique uses specific antibodies to 'tag' and highlight proteins on the surface of cells. For example, IHC can determine if a breast cancer tumour is oestrogen-receptor positive, which affects treatment options and if certain hormone therapies will be effective.
• Molecular Pathology (Genetic Testing): Analysing DNA and RNA within the tissue sample can identify specific gene mutations. This is critical in modern cancer treatment (precision medicine), as it helps doctors to select highly targeted drugs that attack the cancer's unique genetic profile.

What a pathology report might contain.

Anatomical pathology reports are complex and use terms which are unfamiliar. You should always discuss the report findings with your doctor.

In addition to the clinical information provided by the doctor on the request form, a typical pathology report may contain the following sections:

• Specimen site – This shows where on the body the sample was taken from. For example: Fine needle aspiration from left upper quadrant of thyroid gland.
• Macroscopic information – This describes the sample with the naked eye. For example: 5 x 8 mm resection biopsy with a 4 x 3 mm area of increased pigmentation with irregular margins.
• Microscopic examination - This describes the sample under the microscope. This will often include information on stains used and details of the edges (margins) of the sample. This may include IHC results.
• Ancillary studies - If molecular testing was done, the results may be included on the report. For example: BRAF mutation testing performed, BRAF negative.

How your tissue sample is prepared and investigated

When your tissue sample arrives in the lab it is given an identification (ID) number and your information is entered into the laboratory computer information system.

1. A scientist describes and records what your sample looks like to the naked eye – this is called a macroscopic examination or a gross dissection. The scientist measures and weighs the tissue and selects important areas for the pathologist to look at.

2. Your specimen is inserted into a cassette and placed in a tissue processor. The tissue is passed through a series of chemicals to remove water. Depending on the size of the specimen this can take many hours to complete.

3. Once processed, your specimen is embedded in molten wax. When this has cooled and hardened, the tissue block can be cut into extremely thin sections. The scientist will use an instrument called a microtome to precisely cut very thin layers of your tissue - often just a few micrometres thick.

4. Tissue sections are floated on a warm bath and lifted onto slides. The slides are stained with H&E, which colours the tissue purple blue and pink. This allows the pathologist to see all the different structures in your tissue. Special stains may be added if needed when the standard H&E stain is not enough to identify certain cells, organisms, proteins or tissue components.

After the specimen has been through processing in the laboratory it comes to the anatomical pathologist who will look at the slide through a microscope. They will look for:

• normal versus abnormal cells
• infection
• benign or malignant changes
• tumour type and grade
• whether surgical margins are clear

Once completed, the anatomical pathologist will prepare a report for your doctor.

Questions to ask your doctor

The choice of tests your doctor makes will be based on your medical history and symptoms. It is important that you tell them everything you think might help.

You play a central role in making sure your test results are accurate. Do everything you can to make sure the information you provide is correct and follow instructions closely.

Talk to your doctor about any medications you are taking. Find out if you need to fast or stop any particular foods or supplements. These may affect your results. Ask:

• Why does this test need to be done?
• Do I need to prepare (such as fast or avoid medications) for the sample collection?
• Will an abnormal result mean I need further tests?
• How could it change the course of my care?
• What will happen next, after the test?

More information

Pathology and diagnostic imaging reports can be added to your My Health Record. You and your healthcare provider can now access your results whenever and wherever needed.

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