Medical history and physical exam
The medical history of the patient is typically examined first. The clinician may ask when the changes on the skin first appeared, if it has changed in size or appearance, and if it is causing any symptoms (pain, itching, bleeding, etc.). The clinician will ask about possible risk factors for skin cancer, such as a history of tanning and sunburns, and if you or anyone in your family has had skin cancer.
During the physical exam, the clinician will note the size, shape, color, and texture of the area(s) in question, and whether they are bleeding, oozing, or crusting. The rest of body may be checked for moles and other spots that could be related to skin cancer.
The lymph nodes (small, bean-sized collections of immune cells) may also be checked. Lymph nodes are located under the skin in the neck, underarm, or groin near the abnormal area. When melanoma spreads, it often goes to nearby lymph nodes first, enlarging them. This could suggest that melanoma might have spread there. If your primary clinician suspects melanoma, you may be referred to a dermatologist, who will look at the area more closely.
The clinician may also use dermoscopy (also known as surface microscopy or epiluminescence microscopy). Dermoscopy is used to examine pigmented or non-pigmented lesions for changes that are not visible to the naked eye.
Skin biopsies
If the dermatologist thinks a spot might be a melanoma, a skin sample will be removed from the suspicious area and sent to a lab to be looked at under a microscope. This is called a skin biopsy.
There are many methods to performing a skin biopsy; the clinician will decide on one based on the size of the affected area, where it is located, and other factors.
Skin biopsies are done using a local anesthetic (numbing medicine), which is injected into the area with a very small needle. A small prick and a little stinging may be felt as the medicine is injected, but there should not be any immediate pain during the biopsy.
[30] Shave biopsy
Shave (tangential) biopsy
The clinician shaves off the top layers of the skin with a small surgical blade. Typically, only the epidermis and the outer part of the dermis are removed, although deeper layers can be removed if needed. A shave biopsy is useful in diagnosing skin diseases and in sampling moles when the risk of melanoma is low.
[31] Punch biopsy
Punch biopsy
For a punch biopsy, the doctor uses a tool that looks like a tiny round cookie cutter to remove a deeper sample of skin. The doctor rotates the punch biopsy tool on the skin until it cuts through all the layers, including the dermis, epidermis, and the upper parts of the subcutis. The sample is removed and the edges of the biopsy site are often stitched together.
Incisional and excisional biopsies
To examine a tumor that may have spread into deeper layers of the skin, the clinician may use an incisional or excisional biopsy. A surgical knife cuts through the full thickness of skin, where a wedge or sliver of skin is removed for examination. An incisional biopsy removes only a portion of the tumor. An excisional biopsy removes the entire tumor, and is usually the preferred method if it can be done.
[32-33] Incisional and excisional biopsy
Biopsies of melanoma that may have spread
Biopsies of areas other than the skin may be needed in some cases. For example, if melanoma has already been diagnosed on the skin, nearby lymph nodes may be biopsied to see if the cancer has spread to them.
Rarely, biopsies may be needed to figure out what type of cancer someone has. For example, some melanomas can spread so quickly that they reach the lymph nodes, lungs, brain, or other areas while the original skin melanoma is still very small.
Melanoma may also be found elsewhere in the body without ever finding a spot on the skin. This may be because some skin lesions go away on their own after some of their cells have spread to other parts of the body. Melanoma can also start in internal organs, but this is very rare, and if melanoma has spread throughout the body, it may not be possible to tell where it started. This can sometimes cause confusion about what kind of cancer it is.
Special lab tests can be done on the biopsy samples that can tell whether it is a melanoma or some other kind of cancer. This is important because different types of cancer are treated differently.
[34] Fine needle aspiration biopsy
Fine needle aspiration biopsy
A fine needle aspiration (FNA) biopsy is used to biopsy large lymph nodes near a melanoma to find out if the melanoma has spread to them. The clinician uses a syringe with a thin, hollow needle to remove very small pieces of a lymph node or tumor. FNA biopsies are not as invasive as some other types of biopsies, but may not always collect sample material to tell if the affected area is melanoma. If so, a more invasive type of biopsy may be needed.
Surgical (excisional) lymph node biopsy
This procedure removes an enlarged lymph node through a small incision (cut) in the skin. A local anesthetic is generally used if the lymph node is near the surface of the body, but the patient may need to be sedated or even asleep if the lymph node is deeper in the body. This type of biopsy is often done if a lymph node’s size suggests the melanoma has spread, but a FNA biopsy of the node did not find any melanoma cells or was not performed.
Sentinel lymph node biopsy
If melanoma has been diagnosed and has any concerning features (such as being at least a certain thickness), a sentinel lymph node biopsy is done to see if the cancer has spread to nearby lymph nodes, as this may affect treatment options. The biopsy finds the lymph nodes that are likely to be the first affected the melanoma if has spread —these are called sentinel nodes (they stand sentinel, or watch, over the tumor, so to speak).
To find the sentinel lymph node (or nodes), a nuclear medicine physician injects a small amount of a radioactive substance into the area of the melanoma. After the substance has travelled to the lymph node areas near the tumor, a special camera is used to see if the radioactive substance collects in one or more sentinel lymph nodes. Once the radioactive area has been marked, the patient is taken to where the surgery will be done. A blue dye is injected in the same place as the radioactive substance. A small incision is made on the marking, and the lymph nodes are checked to find which one(s) became radioactive and turned blue. These sentinel nodes are then removed and observed under a microscope.
If there are no melanoma cells in the sentinel nodes, no more lymph node surgery is needed. If they are found in the sentinel node, the remaining lymph nodes in this area are removed and looked at as well. This is known as a lymph node dissection.
[35] Sentinel lymph node biopsy
Imaging tests
Imaging tests use x-rays, magnetic fields, or radioactive substances to create pictures of the inside of the body. In this case, they are used to look for the possible spread of melanoma to lymph nodes or other organs in the body. They are not needed for people with very early-stage melanoma, which is very unlikely to have spread.
Imaging tests can also be done to help determine how well treatment is working or to look for possible signs of cancer coming back (recurring) after treatment.
Chest x-ray
This test may be done to help determine whether melanoma has spread to the lungs.
Computed tomography (CT) scan
The CT scan uses x-rays to make detailed, cross-sectional images of the body. Unlike a regular x-ray, CT scans can show the detail in soft tissues (such as internal organs). This test can help tell if any lymph nodes are enlarged or if organs such as the lungs or liver have suspicious spots, which might be due to the melanoma spreading. It can also help show the spread to the lungs better than a standard chest x-ray.
CT-guided needle biopsy: CT scans can also be used to help guide a biopsy needle into a suspicious area within the body. While on the CT scanning table, the doctor moves a biopsy needle through the skin and toward the suspicious area. CT scans are repeated until the needle is in the mass.
Magnetic resonance imaging (MRI) scan
Like CT scans, MRI scans give detailed images of soft tissues in the body. However, MRI scans use radio waves and strong magnets instead of x-rays to create pictures. MRI scans are very helpful in looking at the brain and spinal cord.
MRI scans take longer than CT scans – often up to an hour – and are a little more uncomfortable, as the patient must lie inside a confined, narrow tube.
Positron emission tomography (PET) scan
A PET scan can help show if the cancer has spread to lymph nodes or other parts of the body—it is most useful in people with more advanced stages of melanoma.
The patient is injected with a radioactive substance (usually a type of sugar related to glucose, known as FDG). The level of radioactivity in the substance is very low and it passes out of the body over the next day or so. As the cancer cells in the body grow quickly, and use up energy than a normal cell, they absorb more of the radioactive sugar. A special camera then creates a picture of the areas of radioactivity in the body. The picture is not as detailed as a CT or MRI scan, but it can provide helpful information about your whole body.
[36] Information taken from the National Cancer Institute
[30] Healthwise. Shave Biopsy. Digital image. WebMD, 2015. Web. 4 June 2015.
[31] Healthwise. Punch Biopsy. Digital image. Government of Alberta, 2015. Web. 4 June 2015.
[32] Excisional Biopsy. Digital image. Oral Biopsies. Exodontia.Info, 2015. Web. 4 June 2015.
[33] Incisional Biopsy. Digital image. Oral Biopsies. Exodontia.Info, 2015. Web. 4 June 2015.
[34] Healthwise. Fine needle aspiration biopsy (FNA). Digital image. Government of Alberta, 2015. Web. 4 June 2015.
[35] Winslow, Therese. Sentinel lymph node biopsy. Digital image. Sentinel Lymph Node Biopsy. National Cancer Institute, 2008. Web. 4 June 2015.
[36] “How Is Melanoma Skin Cancer Diagnosed?” How Is Melanoma Skin Cancer Diagnosed? American Cancer Society, 20 Mar. 2015. Web. 08 June 2015.