Melanoma is a type of skin cancer that develops from pigment-producing cells known as melanocytes. When melanocytes become damaged or start growing out of control, it can result in the formation of malignant tumors, which are dangerous and can spread to other parts of the body. Melanoma is the most serious and deadly form of skin cancer, however it often starts out looking like a mole or other benign skin growth. This leads many to wonder – can something that looks like melanoma end up being harmless?
What does melanoma typically look like?
Melanoma lesions usually have an irregular shape with uneven coloring and borders. They may be asymmetrical, with two very different halves. The color is often uneven, with different shades of black, brown and tan. Melanoma can also be different colors mixed together in a single lesion. The borders tend to be uneven and may appear jagged or notched. Melanoma lesions are often larger than 6 millimeters in diameter (about the size of a pencil eraser). However, they can sometimes be smaller when first detected. Over time, the lesion may change in size, shape, coloring or texture. Other warning signs include:
- A new spot that is different from surrounding moles
- A sore that doesn’t heal and bleeds easily
- An existing mole that starts changing size, shape or color
- A spot that looks shiny, waxy, smooth and pale or pink
- Dark lesions on palms of hands, soles of feet, under nails or in mouth
So in summary, the ABCDE criteria are telltale signs of possible melanoma:
Asymmetry – the two halves look very different
Border – the edges are ragged, notched or blurred
Color – varied shades, uneven pigmentation
Diameter – larger than 6mm, about the size of a pencil eraser
Evolving – changes in size, shape, color, elevation, any new symptom
What are some benign skin growths that can mimic melanoma?
While the ABCDE guidelines help identify features characteristic of melanoma, there are many other benign moles and skin lesions that can look concerningly similar to melanoma. Some non-cancerous growths that can be mistaken for melanoma include:
Atypical (dysplastic) nevi – These are unusual looking but harmless moles that may have an irregular shape and coloration. They are more common in people with many moles or a family history of melanoma. Over time they may slowly change.
Seborrheic keratosis – These very common noncancerous growths often appear on the face, chest or back of middle-aged or older people. They may be light tan to black in color with a waxy, pasted-on look. Their borders tend to be relatively even.
Solar lentigines (liver spots) – Rounded brown to black spots that develop slowly over years on sun-exposed areas of skin. They are usually harmless but should be monitored for changes.
Pigmented actinic keratosis – Rough, scaly patches on sun-damaged skin that develop a dark pigment. They are precancerous lesions that can very rarely progress to squamous cell carcinoma.
Melanocytic nevi (moles) – Acquired moles can resemble melanoma. Features like symmetry, even coloring and distinct borders help indicate they are benign.
Blue nevus – A usually benign mole that is blue-black in color. It may also have a regular, smooth border and dome-shaped elevation.
Spitz nevus – A pink or reddish bump most often appearing on the face or legs of children. It tends to grow rapidly then stabilize.
Hemangioma – A benign growth of blood vessels that appears as a red/purple lesion on the skin. It is commonly known as a strawberry mark.
So in summary, while many benign skin lesions can look worrisomely similar to melanoma, a skilled dermatologist can discern key differences during a clinical skin exam. Features like symmetry, smooth borders and unchanged nature over time help rule out melanoma.
How can you tell if a suspicious spot may be melanoma?
Because melanoma can closely resemble other skin growths, any new or changing lesion that looks concerning should be evaluated by a dermatologist. There are certain clues that help dermatologists determine if a spot may be melanoma rather than benign.
Features that raise suspicion of melanoma
- Asymmetry – two very different looking halves
- Irregular, blurred or notched borders
- Varied colors – shades of tan, brown and black
- Large diameter – bigger than 6mm
- Rapid increase in size, elevation or symptoms
- History of excessive sun exposure or blistering sunburns
- Older age, male gender, fair skin, many atypical moles
- Family history of melanoma
- New spot evolving over weeks to months, rather than years
- Bleeding, itching or crusting of the lesion
Tests to evaluate suspicious spots
In addition to a visual inspection, dermatologists have other techniques that aid in evaluating suspicious moles:
Dermoscopy – A special magnifying instrument helps examine pigment patterns, blood vessels and skin texture to detect melanoma early.
Skin biopsy – Removing all or part of the concerning growth for microscopic examination by a pathologist. This is the gold standard for confirming melanoma.
Photography monitoring – Comparing photos taken over several months helps identify worrisome changes. Useful for ambiguous or difficult to biopsy growths.
Confocal microscopy – Advanced imaging to visualize cells and structures deeper in the skin without removing tissue. Can provide clues to diagnosis.
Genetic tests – Newer tests analyze skin cells for genetic mutations linked to increased melanoma risk. Still being integrated into diagnosis.
So in summary, an expert dermatologic workup of a suspicious lesion – including inspection, dermoscopy, biopsy and other tools – is critical for accurate melanoma detection and ruling out benign mimics.
How do dermatologists distinguish melanoma from benign growths?
Distinguishing a melanoma from benign moles and other skin lesions takes considerable medical training and experience. Dermatologists rely on both “pattern recognition” based on years of examining thousands of growths as well as purposeful analysis using these strategies:
Assess ABCDE criteria
Carefully evaluating asymmetry, border irregularity, color variegation, large diameter and evolution over time provides important clues to the diagnosis. Melanoma tends to exhibit several worrisome features.
Compare to other skin lesions
Noting similarities and differences to other moles and marks on the patient aids in determining if a new spot looks foreign or “ugly duckling”. Comparisons also discern changes in existing growths.
Consider clinical history
Factors like patient age, skin type, sun exposure, family history and number of moles influences risk. For example, sudden change in a mole on the arm of a 50-year-old male with high sun exposure is suspicious.
Use dermoscopy
This specialized magnifying tool allows seeing colors, patterns and blood vessels not visible to the naked eye. Irregular pigment networks, streaks and dots help identify melanoma.
Assess thickness and invasion
Depth of growth into layers of skin and local tissue invasion are revealed by biopsy and imaging. Deeper invasion points to higher malignancy potential.
Observe evolution
Comparing photographic monitoring and patient reports over months to years helps determine if changes are consistent with a benign mole or worrisome melanoma.
Consider body site
Location provides clues. For example, pigmented lesions on the palms, nail beds and mucous membranes have higher odds of melanoma.
Correlate pathology
Microscopic analysis of biopsy tissue along with genetic tests provide definitive diagnosis of benign nevi versus malignant melanoma based on cellular and structural characteristics.
In summary, dermatologists synthesize visual cues, patient factors, clinical data and pathological findings to accurately discriminate benign mimics from true melanoma. Their extensive training and experience provides the essential nuance.
What are some treatment options if melanoma is diagnosed?
If a suspicious lesion does turn out to be melanoma upon expert dermatological evaluation, important treatment decisions must be made depending on the stage. Early detection leads to better outcomes. Here are the general treatment options based on melanoma progression:
In situ melanoma
This non-invasive stage confined to the outermost skin layer is usually treated by surgical excision to remove the lesion and a margin of normal skin. Topical imiquimod cream may sometimes be used.
Stage 1
For these thin invasive melanomas under 1 mm thick, surgical excision is also standard to ensure clear margins. Sentinel lymph node biopsy helps determine if cancer has spread to local nodes.
Stage 2
Slightly thicker 1-2 mm tumors have a higher chance of spreading. Again surgery is first line, but may be followed by immunotherapy drugs, targeted drugs or radiation therapy.
Stage 3
More advanced melanoma invading nearby lymph nodes requires surgical removal of nodes plus adjuvant immunotherapy or targeted therapy and possibly radiation.
Stage 4
Widespread metastatic melanoma requires systemic treatment with immunotherapy, targeted drugs, chemotherapy, radiation and/or surgery for palliation. Search for drug trials.
In addition to treatment, regular follow up is needed after a melanoma diagnosis to monitor for recurrence. Sun protection and skin exams are imperative. With early detection and proper treatment, melanoma survival rates can be quite high.
Conclusion
While some benign skin lesions can closely mimic melanoma in appearance, an expert dermatologic evaluation can discern telltale signs to rule out cancer. Looking for asymmetry, border irregularity, color variegation and change over time assists diagnosis. A biopsy and microscopic pathology review can definitively confirm the presence or absence of melanoma. If melanoma is detected early when still thin and localized, prompt surgical excision leads to excellent cure rates. Being aware of the warning signs – and seeking prompt dermatology assessment of changing moles – allows cases to be caught at the most treatable stages. Increased public awareness and improving diagnostic tools continue to improve melanoma outcomes. Though challenging to initially distinguish from benign growths, melanoma can be defeated with vigilance.
