Melanoma vs Seborrheic Keratosis: How to Tell the Difference

Jan 25, 2025 | 5 min read

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Melanoma and seborrheic keratosis can appear similar, leading to confusion. Melanoma is a dangerous skin cancer, while seborrheic keratoses are benign growths. 

Recognizing their differences is vital for accurate diagnosis and timely treatment.

melanoma vs seborrheic keratosis

Definition

What Is Melanoma?

Melanoma is a type of skin cancer that develops in melanocytes, the cells that produce pigment. While melanoma accounts for only about 1% of skin cancers, it causes the majority of skin cancer-related deaths due to its aggressive nature. 

It is one of the most serious forms of skin cancer because it can spread quickly to other organs if not detected early.

melanoma example

Picture of a melanoma from a new, dark lesion on the skin

Source:https://www.cancerresearchuk.org/about-cancer/melanoma/pictures-abnormal-moles-skin-change

Types of Melanoma

Melanoma has various subtypes, including:

  • Superficial Spreading Melanoma: The most common type. It starts in the top layer of the skin and gradually grows deeper.
  • Nodular Melanoma: A faster-growing type that appears as a raised bump on the skin.
  • Lentigo Maligna Melanoma: Often seen in older adults, it develops in sun-exposed areas and grows slowly.
  • Acral Lentiginous Melanoma: A rare form occurring on the palms, soles, or under the nails, often in individuals with darker skin tones.

What Is Seborrheic Keratosis?

Seborrheic keratosis is a benign (non-cancerous) skin growth that develops from the outer layer of skin cells. This growth is often mistaken for warts or skin cancer but is harmless and unrelated to UV exposure.

Importantly, seborrheic keratoses are not contagious, meaning they cannot spread from person to person.

Seborrheic Keratosis

Causes and Risk Factors

Melanoma

Melanoma primarily results from mutations in melanocytes caused by ultraviolet (UV) radiation exposure. 

Risk factors include:

  • Prolonged Sun Exposure: Frequent exposure to intense sunlight or artificial sources like tanning beds. Using tanning beds before 20 raises melanoma risk by 47%, increasing with each use.
  • Fair Skin and Light Features: Individuals with fair skin, light hair, and freckles are more prone.
  • Family History: A family history of melanoma increases the likelihood of development.
  • Numerous Moles: Having many moles or atypical ones raises the risk.
  • Weakened Immune System: Individuals with compromised immunity are more vulnerable.

Seborrheic Keratosis

Seborrheic keratoses are not cancerous and don’t result from UV exposure. Instead, their causes include:

  • Age: These growths commonly appear in individuals over 50.
  • Genetics: A family history of seborrheic keratoses increases susceptibility.
  • Unknown Triggers: The exact mechanisms remain unclear, but they are not linked to lifestyle or sun exposure.

Comparison

Melanoma is strongly associated with UV radiation exposure, whereas seborrheic keratoses are not linked to sun exposure at all. 

Both conditions become more common with age; however, seborrheic keratoses are almost exclusively seen in older adults.

Symptoms

Melanoma

Melanoma symptoms often include noticeable changes in existing moles or the appearance of new, unusual skin lesions. These changes are typically evaluated using the ABCDE rule:

  • Asymmetry: One half of the mole doesn’t match the other.
  • Irregular Borders: Edges are jagged, blurred, or notched.
  • Color Variations: Multiple colors, including black, brown, white, red, or blue, within a single lesion.
  • Diameter: A size larger than 6 millimeters (about the size of a pencil eraser).
  • Evolving: Changes in size, shape, color, or symptoms like itching or bleeding.
ABCDE rule

Seborrheic Keratosis

Seborrheic keratosis typically appears as waxy, wart-like growths that are painless and harmless. Symptoms include:

  • Well-Defined Edges: Growths have a clear boundary separating them from normal skin.
  • Stuck-On Appearance: They often look as though they are pasted onto the skin.
  • Varied Texture: Growths may feel smooth, waxy, or rough.
  • Color Differences: They vary in shades of brown, tan, or black, but remain consistent in hue within a single lesion.
  • No Itching or Pain: They rarely cause discomfort unless irritated by clothing or friction.

Comparison

While melanoma and seborrheic keratosis can both appear as skin growths, their symptoms are distinct. 

Melanoma often presents danger indicators, including irregular borders, evolving size, and multiple colors, which are absent in seborrheic keratosis. 

In terms of physical appearance, seborrheic keratosis typically has a waxy or "stuck-on" look, whereas melanoma may appear irregular and invasive. 

Additionally, melanoma lesions may itch or bleed, while seborrheic keratosis is usually asymptomatic.

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Diagnosis

Melanoma

Melanoma diagnosis involves a thorough skin examination and specialized tests to confirm its presence:

  • Physical Examination: A dermatologist inspects the skin, focusing on any abnormal moles or growths.
  • Dermatoscopy: A handheld device magnifies the lesion, providing a closer look at its structure and pigmentation.
  • Skin Biopsy: A skin biopsy involves removing a small sample of a suspicious lesion to examine it under a microscope and confirm if it is melanoma.
  • Imaging Tests: Advanced cases may require imaging, such as CT scans, to determine if the cancer has spread.
Dermatoscopy

Dermatoscopy

Seborrheic Keratosis

Seborrheic keratosis is usually diagnosed based on the distinct appearance:

  • Visual Examination: A dermatologist can typically identify seborrheic keratoses without additional tests due to their characteristic “stuck-on” appearance.
  • Dermatoscopy: This tool may be used to differentiate benign seborrheic keratoses from other pigmented lesions.
  • Biopsy (Rare): In uncertain cases, a small biopsy is performed to rule out melanoma or other skin cancers.

Comparison

Melanoma diagnosis often requires a biopsy and imaging, while seborrheic keratosis is usually identified visually.

Both conditions may involve dermatoscopy, but melanoma demands more advanced diagnostic methods.

Treatment

Melanoma

Treatment for melanoma depends on its stage and extent of spread. Common approaches include:

  • Surgical Removal: Early-stage melanoma is often treated by excising the lesion along with some surrounding healthy tissue.
  • Lymph Node Removal: If cancer has spread to nearby lymph nodes, they may also be removed.
  • Advanced Treatments: For metastatic melanoma, options include immunotherapy, targeted therapy, or radiation therapy, depending on the case.
  • Follow-Up Care: Regular check-ups are crucial to monitor for recurrence or new lesions.

Seborrheic Keratosis

Seborrheic keratoses are benign and often don’t require treatment. However, removal may be considered for cosmetic reasons or irritation. Methods include:

  • Cryotherapy: Freezing the growth with liquid nitrogen causes it to fall off.
  • Curettage: The lesion is scraped off under local anesthesia.
  • Electrosurgery: Burning the lesion with an electric current is an option for thicker growths.
  • Laser Therapy: A laser may be used to remove lesions and improve skin appearance.

Comparison

Melanoma requires immediate medical intervention due to its life-threatening nature. Seborrheic keratoses can often be left untreated.

Melanoma treatment involves complex therapies like surgery and immunotherapy, while seborrheic keratoses are treated with simple outpatient procedures.

Complications

Melanoma

Melanoma can lead to severe complications, especially if it spreads beyond the skin. These include:

  • Metastasis: Melanoma can spread to areas like the lymph nodes, lungs, liver, or brain. This spread makes the condition harder to treat.
  • Recurrence: Melanoma can come back even after treatment, so long-term monitoring is needed.
  • Organ Failure: Advanced melanoma affecting vital organs can lead to life-threatening complications.
  • Emotional Impact: The diagnosis and treatment process can cause anxiety, depression, or stress.

Seborrheic Keratosis

Seborrheic keratosis is benign and typically doesn’t cause complications. However, some issues may arise in rare cases:

  • Irritation: Lesions located in friction-prone areas can become irritated, causing discomfort or bleeding.
  • Misdiagnosis: Their resemblance to melanoma or other skin cancers may lead to unnecessary concern or testing.
  • Infection: Improper attempts to remove them at home can result in infection.

Prevention

Melanoma

Preventing melanoma involves minimizing risk factors and adopting healthy skin care habits:

  • Limit Sun Exposure: Avoid prolonged sun exposure, especially during peak hours (10 a.m. to 4 p.m.).
  • Use Sunscreen: Apply a broad-spectrum sunscreen with at least SPF 30 daily, even on cloudy days.
  • Protective Clothing: Wear hats, sunglasses, and long-sleeved clothing to shield your skin from harmful UV rays.
  • Avoid Tanning Beds: Artificial UV exposure significantly increases the risk of melanoma.
  • Regular Skin Checks: Perform self-examinations to monitor moles and see a dermatologist for professional check-ups annually.

Seborrheic Keratosis

There are no specific preventive measures for seborrheic keratoses, as they are not caused by external factors.

Frequently Asked Questions

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Conclusion

Understanding the differences between melanoma and seborrheic keratoses is essential for accurate diagnosis and care. 

While melanoma is a potentially life-threatening skin cancer often linked to UV exposure, seborrheic keratoses are benign growths caused by genetic and age-related factors. 

Both conditions may appear as skin lesions, but melanoma requires urgent medical attention due to its aggressive nature. 

If you notice unusual skin changes, consulting a healthcare professional is crucial to ensure proper evaluation and treatment.

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