How is Melanoma Diagnosed?
The majority of melanomas are diagnosed after a suspicious lesion or mole has been removed from a person’s body, sent to a pathology lab for evaluation, and declared to be cancerous.
The process of removing all or part of the lesion or mole for evaluation under a microscope is called a biopsy. Once identified as melanoma, the lesion or mole is called a primary tumor.
The process of finding a melanoma on the skin, in mucosal tissue, or in the eye is as varied as patients are. Sometimes melanoma is discovered by a healthcare provider, such as a dermatologist during a skin exam; an ophthalmologist during an eye exam; or a general practitioner during a regular check-up. Sometimes it is identified by a patient who notices a change in a mole or new lesion. And sometimes it is found by a patient’s spouse, parent, friend, child – even hairstylist.
Once a suspicious mole or lesion is identified, the key is to get a healthcare provider who is knowledgeable about melanoma to look at it, to remove it if s/he suspects it may be melanoma, and to perform a full-body skin exam to look for any other suspicious lesions.
Unfortunately, sometimes melanoma is found when it has already spread. In some rare cases, a skin biopsy reveals metastasized melanoma, not a primary melanoma tumor. And in other cases, melanoma is found already metastasized in the body through an x-ray, scan, or other means. For the purposes of explaining a more common diagnosis progression, this page will discuss a melanoma diagnosis of a primary tumor from a skin biopsy.
The Skin Exam
Your healthcare provider should examine you without clothing so that all areas of skin can be inspected. S/he will pay particular attention to spots you have identified as changed or suspicious and ask whether you have a family history of melanoma. S/he may view suspicious lesions or moles through a dermatoscope and assess the spot using the ‘ABCDE’ criteria:
• Asymmetry – is one half of the lesion/mole different from the other?
• Border – are the edges irregular or scalloped?
• Color – are there different shades or colors in the lesion/mole?
• Diameter – is the lesion/mole greater than 6 mm across?
• Evolving – has the lesion/mole changed over time (e.g. size, shape, color, bleeding, itching)?
Removing the Lesion/Mole
If your healthcare provider suspects that a lesion/mole is melanoma, s/he will perform a skin biopsy. The usual procedure is to remove some or all of the lesion/mole for examination under a microscope by a pathologist or dermatopathologist. A pathologist is a physician who diagnoses disease through laboratory tests and evaluation of cells, tissues, and organs. A dermatopathologist specializes in skin pathology, a subspecialty of dermatology and pathology.
A pathologist or dermatopathologist will examine the tissue to determine if it contains melanoma cells. S/he will write a report about the findings called a pathology report, which will be sent to your physician. Your physician will then review the results with you. If the finding is melanoma, your report will note what stage your melanoma is deemed to be. In nearly all cases of a biopsy of a skin lesion, your stage will be designated either Stage 0, Stage I, or Stage II, because the tissue sample cannot reveal lymph node involvement (Stage III) or distant metastases (Stage IV). If there are details in your pathology report, your medical history, or your physical exam that suggest the melanoma could have spread to lymph nodes or other distant sites in your body, your doctor will recommend further testing to determine if you are Stage III or Stage IV.