Merkel Cell Carcinoma – Symptoms and Causes

ByJanis Updated

Understanding Merkel Cell Carcinoma

Merkel cell carcinoma is an uncommon skin cancer that typically appears as a lump. This fast-growing cancer is also known as neuroendocrine carcinoma of the skin.

People over age 50 face higher risk, especially those with extensive sun damage or weakened immune systems.

This cancer spreads rapidly to other body parts, making early detection crucial. The cancer’s quick growth pattern means it can move beyond the skin to other organs if not treated promptly.

Treatment approaches vary based on whether the cancer remains localized or has spread to other areas of the body.

Signs and Changes

Merkel cell carcinoma first appears as a growth on your skin. This skin cancer can develop anywhere, but most commonly forms in sun-exposed areas.

White individuals tend to develop these growths on the head or neck, while Black individuals more frequently experience them on the legs.

A Merkel cell carcinoma typically looks like:

  • A painless bump on the skin
  • A growth that increases in size rapidly
  • An asymmetrical bump
  • A growth that appears pink, purple, red-brown, or matches your natural skin tone

When medical attention is needed

Contact a healthcare provider if you notice any mole, freckle or bump that:

  • Changes in size, shape or color
  • Grows quickly
  • Bleeds easily after minor trauma (like washing or shaving)

These symptoms warrant prompt evaluation, as early detection of skin cancers improves treatment outcomes.

Causes

The exact origin of Merkel cell carcinoma remains unclear to medical experts. This rare skin cancer develops when skin cells experience DNA mutations.

In healthy cells, DNA provides instructions for normal growth, multiplication, and eventual cell death. However, when DNA changes occur, cancer cells receive different instructions.

These altered instructions tell cancer cells to grow rapidly and avoid dying when they should. This uncontrolled growth leads to an accumulation of abnormal cells that may form tumors.

These tumors can invade nearby healthy tissue and, in some cases, break away to spread to distant body partsโ€”a process called metastasis.

Despite its name, Merkel cell carcinoma likely doesn’t originate in Merkel cells themselves. These cells, located at the base of the skin’s outer layer, connect to nerve endings and help with our sense of touch.

Scientists now believe the cancer starts in different cells, though they haven’t identified the exact type.

The DNA changes triggering Merkel cell carcinoma often have no clear cause. However, research has identified a significant factor: Merkel Cell Polyomavirus. This common virus:

  • Lives harmlessly on human skin
  • Causes no noticeable symptoms
  • Has been strongly linked to many Merkel cell carcinoma cases

While the connection between the virus and cancer development is established, researchers still don’t fully understand the exact mechanisms by which the virus transforms normal cells into cancerous ones.

Other risk factors that may contribute to developing this cancer include:

  • Excessive sun exposure
  • Weakened immune system
  • Advanced age
  • Fair skin

Understanding these potential causes helps healthcare providers identify high-risk individuals and develop appropriate screening protocols.

Risk Factors

Several factors can increase your chance of developing Merkel cell carcinoma:

Skin Type and Sun Sensitivity

People with lighter skin that burns easily face higher risks. This is because they have less melanin, the natural substance that gives skin its color and offers some protection against harmful sun rays.

While this cancer can affect anyone of any skin color, it occurs more frequently in people with white skin than those with Black or brown skin.

UV Exposure

Excessive exposure to ultraviolet light significantly raises your risk. This includes:

  • Natural sunlight without proper skin protection
  • UV light treatments for conditions like psoriasis
  • Regular use of indoor tanning beds

Immune System Weaknesses

People with compromised immune systems face higher risks, including those with:

  • HIV infection
  • Chronic leukemia
  • Organ transplants requiring immunosuppressive medications
  • Other conditions require medications that reduce immune response

Age Factor

While Merkel cell carcinoma can develop at any age, it’s most common in people over 50. The risk continues to increase with advancing age.

Previous Skin Cancer History

Having had other types of skin cancer puts you at greater risk. This cancer is linked to previous cases of:

  • Basal cell carcinoma
  • Squamous cell carcinoma

Complications

Merkel cell carcinoma can spread beyond its original site even after treatment begins. This spread, known as metastasis, typically affects nearby lymph nodes first.

As the disease progresses, it may reach other parts of the body, including:

  • Brain
  • Bones
  • Liver
  • Lungs

When cancer reaches these organs, it can interfere with their normal functions. Metastatic cancer is generally more difficult to treat effectively. The spread of Merkel cell carcinoma to multiple body systems can be life-threatening.

How to Reduce Your Risk

Limit Sun Exposure During Peak Hours

Try to avoid being outside when the sun is strongest, typically between 10 AM and 3 PM in North America.

This applies year-round, even during winter months or on cloudy days. When you must be outdoors during these hours, seek shade whenever possible. Standing under trees, awnings, or using an umbrella can significantly reduce your exposure to harmful rays.

Apply Sunscreen Regularly

Use a broad-spectrum sunscreen with SPF 30 or higher every day, regardless of weather conditions.

Apply it generously to all exposed skin about 15 minutes before going outside. Remember to reapply every two hours, or more frequently if you’re swimming or sweating.

Don’t forget often-missed areas like your ears, the back of your neck, and the tops of your feet.

Sunscreen Tips Why It Matters
SPF 30+ broad-spectrum Protects against both UVA and UVB rays
Apply 15 minutes before sun exposure Allows sunscreen to bond with skin
Reapply every 2 hours Maintains protection throughout the day

Dress for Protection

Wear protective clothing to shield your skin from sun damage:

  • Dark, tightly woven fabrics that cover arms and legs
  • Wide-brimmed hats (at least 3 inches) to protect your face, ears and neck
  • UV-blocking sunglasses that shield your eyes from both UVA and UVB rays

Specialized sun-protective clothing with UPF (Ultraviolet Protection Factor) ratings offers additional protection.

Monitor Your Skin Regularly

Examine your skin once a month for any new growths or changes in existing spots. Use mirrors to check hard-to-see areas like your back, scalp, and behind your ears. Pay attention to all body parts, even those rarely exposed to the sun.

What to look for:

  • New moles or growths
  • Changes in existing spots (size, color, shape)
  • Unusual sensations (itching, tenderness)

Report any concerning changes to your healthcare provider promptly.


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Health Writer

Janis's areas of expertise include nutrition, exercise, stress management, and mental health. She is passionate about educating and empowering people to take control of their health and make positive changes that can last a lifetime. Janis believes that small, sustainable changes are the key to long-term success, and she works with her clients to develop personalized plans that fit their individual needs and lifestyles.