Merkel Cell Carcinoma

Merkel cell carcinoma (MCC) is a rare and aggressive type of skin cancer that originates in the Merkel cells, which are specialized nerve cells found in the skin. These cells are responsible for touch sensation and are located in the epidermis, the outermost layer of the skin.

Causes and Risk Factors

Merkel cell carcinoma is caused by a combination of genetic and environmental factors. The main risk factors include:

• Age: MCC typically affects older adults, with most cases occurring in people over 70 years old.
• UV radiation: Exposure to ultraviolet (UV) radiation from the sun or tanning beds increases the risk of developing MCC.
• Immune system suppression: People with weakened immune systems, such as those with HIV/AIDS or taking immunosuppressive medications, are more susceptible to MCC.
• Merkel cell polyomavirus (MCPyV): This virus is found in about 80% of MCC tumors and is thought to play a role in the development of the disease.

Symptoms

The symptoms of Merkel cell carcinoma may include:

• A firm, painless nodule or bump on the skin, often with a smooth surface
• A lesion that grows rapidly over a period of weeks or months
• A lesion that may be pink, red, purple, or blue in color
• Lesions are typically found on sun-exposed areas of the skin, such as the face, neck, and arms

Diagnosis

Diagnosing Merkel cell carcinoma typically involves a combination of the following:

• Physical examination: A doctor will examine the lesion and assess its size, shape, color, and texture.
• Biopsy: A sample of tissue is removed from the lesion and examined under a microscope for abnormal cells.
• Imaging tests: CT scans, MRI scans, or PET scans may be used to determine if the cancer has spread to other parts of the body.

Treatment

Treatment for Merkel cell carcinoma depends on the stage and location of the disease. Common treatment options include:

• Surgery: Removing the tumor and surrounding tissue is often the primary treatment for MCC.
• Radiation therapy: High-energy rays are used to kill cancer cells and shrink tumors.
• Chemotherapy: Medications are used to kill cancer cells that have spread to other parts of the body.
• Immunotherapy: Treatments that stimulate the immune system to attack cancer cells, such as checkpoint inhibitors, may be used in some cases.

Prognosis

The prognosis for Merkel cell carcinoma varies depending on the stage of the disease. If caught early, MCC can be treated effectively, and the 5-year survival rate is around 70-80%. However, if the cancer has spread to other parts of the body, the prognosis is generally poorer.