What type of cancer is Merkel cell tumor?

Merkel Cell Carcinoma (MCC) is a rare but highly aggressive skin cancer. It originates primarily from Merkel cells in the skin, neuroendocrine cells located in the basal layer of the epidermis that are responsible for sensing touch. This cancer usually presents as rapidly growing, painless skin lumps that are common on the head, neck, and extremities, especially in areas of skin that are chronically exposed to UV rays.

1.Classification of Merkel cell tumors

Merkel cell tumor is classified as a neuroendocrine cancer, also known as neuroendocrine cancer of the skin. This is because Merkel cell tumors have the characteristics of nerve and endocrine cells, can secrete hormone-like substances, and also have the functional characteristics of nerve cells. Merkel cell tumors are more malignant and have a greater risk of metastasis than other types of skin cancer, such as basal cell carcinoma or squamous cell carcinoma.

2.Main Features

High degree of malignancy: Merkel cell tumors are highly aggressive and usually show rapid growth in the early stages and may spread to distant organs such as lymph nodes, lungs, and liver.

The causes of the disease are complex: The pathogenesis of this tumor is usually related to ultraviolet damage, low immune function, and Merkel Cell Polyomavirus (Merkel Cell Polyomavirus, MCPyV) infection.

Predisposed groups: Merkel cell tumors are more common in the elderly, people with low immune function and people with fair skin, especially those who have been exposed to the sun for a long time.

3.Diagnosis and Treatment

The diagnosis of Merkel cell tumor relies on pathological examination, including histology and immunohistochemical staining. Treatment is usually a combination of surgical resection, radiation therapy, and chemotherapy. For advanced or metastatic cases, immunotherapy (egPD-1/PD-L1inhibitors) has become an important treatment approach.

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

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Reference materials

1.American Cancer Society. Merkel Cell Skin Cancer. https://www.cancer.org/cancer/merkel-cell-skin-cancer.html

2.National Cancer Institute. Merkel Cell Carcinoma Overview. https://www.cancer.gov/types/skin/patient/merkel-cell-treatment-pdq