Diagnosis of Melanoma

Medical practitioners use many tests to detect or diagnose cancer. They also perform tests to see if cancer has matured or migrated to other parts of the body from where it began. In other words, metastasis. Imaging examinations, for example, can help us understand if cancer has matured. With the help of imaging tests, the doctors can produce visuals of the inside of the body. Medical practitioners may also conduct tests to determine which treatments will be suitable and effective for the individual. 

A biopsy of the suspicious skin region, known as a lesion, is the only way for the doctor to tell if it is cancerous in the case of melanoma. In biopsy, a doctor removes a small sample of tissue. This then goes to the laboratory. Finally, the laboratory examines or tests it.

The following section discusses melanoma diagnosis options. However, all these tests won’t be for to every person. It is basically like no one size fits all as it can differ from one individual to another. The doctor will consider numerous aspects when choosing the diagnostic test for each person. Listed below are some of them.

Biopsy and pathological examination of a skin lesion

Few of the tests may indicate the presence of cancer or the tumor, but only a biopsy can provide a definite diagnosis. The doctor gives a local anaesthetic before biopsy. The doctor gives it to numb the region. An anaesthetic is a drug that prevents you from feeling discomfort or pain in the body. They will further remove a portion or all the suspicious skin growth. Usually, they preserves the complete lesion. They do this to evaluate the thickness of the suspected cancer and its magin.

A pathologist or a dermatopathologist then analyses the samples obtained during the biopsy to find out if the lesion is a melanoma. A pathologist is a clinician who specialises in diagnosing disease by interpreting laboratory tests and accessing the cells, tissues, and organs. A dermatopathologist is a pathologist who specialises in utilising a microscope and another laboratory testing to diagnose skin cancer and also other skin problems. The pathologist or dermatopathologist will review and write a pathology report containing the following information. 

  • Melanoma thickness 
  • Presence or absence of Ulceration. 
  • The report will include the type or subtype of melanoma if the cells are dividing, known as mitotic rate. 
  • Tumor infiltrating lymphocytes are immune cells that infiltrate the tumors. 

Margin status is the presence of melanoma cells at the biopsy site or sample’s deep and peripheral edges. However, prognosis and treatment response considers the presence or absence of specific markers.

Types of melanoma of the skin described by pathologists

The four most common types of skin melanoma are as follows :

Superficial spreading melanoma is the most prominent type, accounting for 70% of all melanomas. It usually grows from a mole that already exists.

Lentigo maligna melanoma – Melanoma of this sort is more common in adults over 50. It usually starts on the face, ears, and arms. In other words, frequently exposed to the sun skin.

Nodular melanoma – Melanomas of this type account for around 15% of all melanomas. It usually matures and shows as a lump on the skin. Its typically in shades of black, although it can also be pink or red.

Acral lentiginous melanoma –

Acral lentiginous melanomas are melanomas that develop on the palms of the hands, soles of the feet, and sometimes even under the nail bed. It can happen to those with darker complexions. Sun exposure / UV radiations have little effect on Acral lentiginous melanoma.

Subtypes of melanoma defined by gene mutations

Classification of melanoma cells is based on how they appear under a microscope. Below mentioned are some of them. Melanoma can now be classified into molecular or genetic subtypes, according to new research and clinical trials. The molecular categories are based on the mutations, distinct genetic changes in the melanoma cells. The following are examples of genetic changes.

  • BRAF mutations –  The most familiar genetic change in melanoma is the BRAF gene, which mutates in about 50% of cutaneous melanomas.
  • NRAS mutations –  People with the tumor will have NRAS is mutations. The figure is approximately around 20%. 
  • NF-1 mutations –  NF-1 mutations are present in the tumors of around 10% to 15% of people with melanoma.
  • KIT mutations – are common in melanomas that mature and develop from mucus membranes, melanomas on the hands or feet, and melanomas seen in chronically sun-damaged skin, such as lentigo maligna melanoma.

All melanomas will not have BRAF, NRAS, NF-1, and KIT gene alterations. Other genetic abnormalities in these cancers lead them to grow and mature. Researchers are attempting to target other mutations discovered in these malignancies in clinical studies. 

The classification of melanoma into subtypes based on genetic variations can significantly impact the therapeutic options available for advanced melanoma. Targeted therapy is a method of treating invasive melanoma by focusing on specific mutant genes. In the types of treatment and latest research sections, you may learn more about targeted therapy. 

Melanoma tumor thickness

The most dependable factor that helps doctors forecast the danger of the cancer spreading is the thickness of the primary melanoma tumor. To do so, The pathologist will take measurements from near the top of the epidermis down to the bottom of the melanoma in the underlying skin or the fatty tissue below.

Thin – Thin melanoma tumors are less than 1mm thick. Melanomas are thin and have a low probability of spreading to the regional lymph nodes or distant body sections. 

Intermediate – An intermediate-thickness melanoma is between the range of 1 mm and 4 mm.

Thick – A thick melanoma is a melanoma from more than 4 mm thickness. However, this can lead to higher chance of recurrence. It is possible after the completion of the treatment. If this occurs, it is because cancer has already matured and developed to other parts of the body at the period of diagnosis.


The pathology report specifies the presence or absence of ulceration in the original melanoma. Ulceration is the loss of the skin’s surface above the melanoma tumour. Ulcerated Melanoma is responsible for to increasing the risk of developing or spreading and its recurrence.

Mitotic rate

The mitotic rate, which measures the amount of cell proliferation, is another pathological aspect of melanoma. The number of dividing cells per millimetre squared is the unit of measurement. When combined with the thickness and existence of ulceration, it can assist and assess prognosis or the likelihood of its recovery. 

Additional evaluation after a diagnosis of melanoma

A specialist examines a patient after an initial diagnosis of melanoma. The doctor will conduct a thorough medical history, including any symptoms or signs that you may be experiencing. And to conduct a thorough physical examination, including a full skin examination and a lymph node inspection. The goal of these tests is to find risk factors and signs and symptoms that indicate melanoma has spread beyond the original site.

The risk of recurrence of the main or the chief melanoma determines the initial assessment. Most people with thin melanoma less than 1mm thick don’t need to look for metastases or spread any further. 

More extensive testing, such as the Imaging tests mentioned, maybe undertaken for people with a higher risk of melanoma. Normally, this succeeds the the surgical procedure or the management. As a result, after discussions with the medical team about the stage of cancer, the doctors determine the scope of melanoma. Further testing for high risk or later stage melanoma may also involve the following depending on the outcomes of the examinations and the pathology report of the primary melanoma tumor. 

Ultrasound –

An ultrasound employs sound waves to produce images of the internal organs, including the lymph node basins, which are groupings of the lymph nodes and the soft tissues.

Computed tomography scan (CT or CAT) scan –

A CT scan uses x rays captured from various angles to create images of the inside of the body. A computer combines these images into a detailed, three-dimensional image that reveals any anomalies or malignancies. To determine the size of a tumor if the melanoma has matured and spread, one can use the CT scan. However, pathologists use a specific dye called a contrast medium is sometimes to improve the quality of the image or the image detail. A procedure, that proceeds the CT scan. Doctors either inject this dye directly into the patient’s vein, or the patients take it in the form of a tablet or drink. 

Magnetic resonance imaging (MRI) –

An MRI Scan uses magnetic rays rather than X-rays to provide detailed body images. Tumors’ size detection happens through Magnetic resonance imaging, also known as MRI scans. However, doctors use a specific dye, contrast medium to create a crisper image. Doctors either inject this dye directly into the patient’s vein, or the patients take it in the form of a tablet or drink. 

Positron emission tomography (PET) scan –

Doctors frequently pair PET Scans and CT. This results in a PET – CT scan. However, your doctor may refer to this technique simply as a PET Scan. A PET scan is a technique for generating images of all the organs and tissues within the body. The doctor injects a small amount of radioactive sugar material into the patient’s body. The cells that use the most energy absorb more of the radioactive substance since they use energy actively. A scanner, then detects this material which produces images inside the body. 

Lymphatic mapping and Sentinel lymph node biopsy

Lymph nodes are little bean-shaped structures that aid in the prevention of infection. Melanoma can spread to the lymph nodes and other regions of the body by growing deep into the inner layers of the skin. 

Sentinel lymph nodes biopsy, in other words is SNBL or SNB. A surgical procedure or treatment allows a clinician to determine whether cancer has matured and progressed to the lymph nodes. To transport cancer from the site of origin to the lymph nodes, doctors use the lymphatic system. The first lymph node the lymphatic system empties is a sentinel lymph node. Because melanoma can start and mature anywhere on the skin, each patient’s lymph nodes will be different depending on where cancer began.

A dye and a harmless radioactive substance are injected as close as feasible to the melanoma site to locate the sentinel lymph node. Doctors track the material until it reaches the sentinel lymph node. The doctor then removes one or more of these lymph nodes to look for melanoma cells, leaving the rest of the lymph nodes in the area intact. These are delivered to a pathologist, who examines the lymph nodes and issues a summary or a report.

If melanoma cells are not identified in the sentinel lymph nodes, no further lymph node surgery is required. This is known as a positive sentinel lymph node if the sentinel lymph node includes melanoma. This indicates that the infection has spread. More lymph nodes were remotely removed in the past, a procedure known as lymph node dissection. From the recent data received, the surgery has a little effect on how long the patients live. In most cases, regular physical examination and lymph node ultrasounds are recommended instead of a lymph node dissection.

Lymphatic mapping

When the melanoma is more than 1.0 mm thick or has ulceration, lymphatic mapping and SNB are frequently used. Sentinel lymph node mapping is not usually advised for melanomas smaller than 0.8mm thick without ulceration. This is due to the small chance of malignancy that has progressed to the lymph nodes. However, suppose there are any symptoms that the melanoma is more aggressive or majorly concerning, such as ulceration or a high mitotic rate. In that case, SNB may be explored for melanomas between 0.8 and 1.0mm thick. Based on this, and also other aspects of the underlying melanoma, as well as other variables, your doctor will discuss whether this technique is recommended or not. 

Sentinel lymph node mapping is best performed concurrently with melanoma removal surgery. This is because surgery can alter lymphatic drainage patterns. In rare cases, performing both processes simultaneously may compromise the procedure’s reliability. After surgery, doctors may recommend Sentinel lymph nodes mapping for some patients. SNB has a few adverse effects, but infection seroma near the surgical region, numbness, and reopening of the surgical area is very much possible. Lymphedema is the accumulation of lymph fluid in the body. Discuss what to expect with your medical practitioner and the team and how side effect management will be carried out. 

After all the diagnostic tests are completed, your medical practitioner will have a thorough look at all of the results with you. If the diagnosis is cancer, these results also help the doctor describe cancer and this process is called staging.