Merkel Cell Carcinoma

Overview of Merkel Cell Carcinoma

Merkel cell carcinoma (MCC) is a rare and aggressive form of skin cancer that develops in the Merkel cells, located in the skin’s outer layer (epidermis). These neuroendocrine cells are involved in the sense of touch. Merkel cell carcinoma typically presents as a fast-growing, painless nodule on sun-exposed areas such as the face, neck, or arms. Though rare, this cancer can spread quickly to other parts of the body, making early detection and treatment crucial.

Symptoms

The first sign of Merkel cell carcinoma is usually a small, firm nodule that can be skin-colored, red, blue, or purple. These lumps are often found on sun-exposed areas, but they can appear anywhere on the body. Key characteristics of MCC include:

  • Rapid growth
  • Dome-shaped or raised appearance
  • Skin-colored or reddish in tone
  • Firm and painless to the touch

Causes and Risk Factors

Several risk factors increase the likelihood of developing Merkel cell carcinoma:

  • UV light exposure: Prolonged exposure to sunlight or tanning beds is a major risk factor.
  • Weakened immune system: Conditions like HIV, organ transplants, or certain cancers can reduce the immune system’s ability to fight off this cancer.
  • Age: People over the age of 50, especially those with lighter skin tones, are at a higher risk.
  • Merkel cell polyomavirus (MCP): Most cases of MCC are linked to this virus, but it is still unclear why it leads to cancer in some individuals.

Diagnosis

Merkel cell carcinoma is diagnosed through a skin biopsy. A dermatologist will remove a small sample of the tumor to check for cancer cells. Other diagnostic tests, such as a CT scan or a PET scan, may be used to determine if the cancer has spread to other areas of the body.

Stages of Merkel Cell Carcinoma

Merkel cell carcinoma is staged based on the extent of its spread:

  • Stage 0: Cancer is limited to the outer layer of skin.
  • Stage I-II: Cancer has spread deeper into the skin or to nearby tissues.
  • Stage III-IV: Cancer has spread to lymph nodes or distant organs.

Treatment Options

Treatment for Merkel cell carcinoma depends on the stage of the cancer. Common treatments include:

  • Surgery: Removal of the tumor through procedures like Mohs surgery or wide local excision, often followed by a lymph node dissection.
  • Radiation Therapy: Used after surgery to reduce the risk of recurrence or as a primary treatment for inoperable tumors.
  • Chemotherapy and Immunotherapy: For more advanced stages, these therapies may be used to kill cancer cells or boost the immune system to fight the cancer.

Prevention and Prognosis

To reduce the risk of Merkel cell carcinoma, it’s important to minimize UV exposure by:

  • Wearing sunscreen with at least SPF 30
  • Avoiding tanning beds
  • Wearing protective clothing when outdoors

Merkel cell carcinoma often returns after treatment, so regular follow-up appointments are essential. The outlook depends on the stage of the cancer at diagnosis, with early-stage cases having a higher survival rate. However, advanced-stage MCC can be more challenging to treat, especially if it has spread to other organs.