What is Merkel cell tumor?

Merkel Cell Carcinoma (MCC) is a rare but highly malignant skin cancer that originates from Merkel cells, which are neuroendocrine cells located in the epidermis of the skin and are responsible for sensing light touch. Merkel cell tumors tend to grow rapidly, have a high risk of metastasis, and are common in areas of the skin that are exposed to the sun, such as the face, head, neck, and arms. Although the cause is not fully understood, its onset is closely related to ultraviolet exposure, immunosuppression, and certain viral infections (such as Merkel cell polyomavirus).

Merkel cell tumors most commonly appear as hard, painless nodules on the skin that are usually red, purple, or blue in color. The size of the nodule is usually between 1-2cm, but it can grow rapidly. It is highly malignant and easily metastasizes to surrounding lymph nodes and distant organs (such as lungs, liver, bones, etc.).

1.High-risk groups: The occurrence of Merkel cell tumor is closely related to the following risk factors:

Ultraviolet exposure: People with long-term sun exposure, especially those with fair skin, are at higher risk.

Immunosuppression: such as organ transplant patients, AIDS patients, and people receiving immunosuppressive treatment.

Age and gender: It is more common in people over 50 years old, and is slightly higher in men than in women.

Viral infection: Merkel cell polyomavirus (MCPyV) is considered an important pathogenic factor.

2.Treatment and prognosis: The treatment of Merkel cell tumor needs to comprehensively consider the stage of the disease and the patient's health status. Treatment usually includes surgery, radiation therapy, and immunotherapy (such asPD-1/PD-L1inhibitors). For cases detected early, better local control can be achieved through surgical resection combined with radiotherapy. However, advanced or metastatic cases have a poorer prognosis, with significantly lower five-year survival rates.

Precautions: Avoid excessive sun exposure, especially during periods of strong UV rays. It is especially important for people at high risk to use sunscreen, wear protective clothing, and regularly check for abnormal skin changes.

(Click to view an introduction to drugs for the treatment of Merkel cell tumors.)

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Reference materials

1.Mayo Clinic. Merkel Cell Carcinoma.

https://www.mayoclinic.org/diseases-conditions/merkel-cell-carcinoma/symptoms-causes/syc-20351078

2.American Cancer Society. What Is Merkel Cell Carcinoma?

https://www.cancer.org/cancer/merkel-cell-skin-cancer/about/what-is-merkel-cell.html