Skin cancer: Merkel cell carcinoma (MCC)

• What is Merkel Cell Carcinoma (MCC)
• Statistics on Merkel Cell Carcinoma (MCC)
• Risk Factors for Merkel Cell Carcinoma (MCC)
• Progression of Merkel Cell Carcinoma (MCC)
• Symptoms of Merkel Cell Carcinoma (MCC)
• Clinical Examination of Merkel Cell Carcinoma (MCC)
• How is Merkel Cell Carcinoma (MCC) Diagnosed?
• Prognosis of Merkel Cell Carcinoma (MCC)
• How is Merkel Cell Carcinoma (MCC) Treated?
• Merkel Cell Carcinoma (MCC) References

What is Merkel Cell Carcinoma (MCC)

Merkel cell carcinoma (MCC) is a rare, aggressive skin cancer that predominantly affects elderly Caucasians. It has a tendency to recur locally and spread to different parts of the body.

Statistics on Merkel Cell Carcinoma (MCC)

Anybody can get MCC, but it is more common in elderly Caucasians and people who have weakened immune systems due to medication or infection with chronic diseases (e.g. HIV). It is also more common in males than females.

Risk Factors for Merkel Cell Carcinoma (MCC)

The cause of MCC is not yet known, but both sun exposure and immune suppression are thought to play important roles.

It is more likely that one will get MCC in:

• Areas of the body which are not covered by clothes and are exposed to the sun.
• People who regularly expose themselves to a high UV index (e.g. people out in the sun between 12-2pm).
• People who have a weak immune system as a result of certain diseases (e.g. HIV).
• An infection with the polyoma virus, as this virus has been shown to be related to the development of MCC.

Progression of Merkel Cell Carcinoma (MCC)

This type of tumour spreads through the lymphatic system, starting from lymph nodes close to where the skin lesion is, and spreading to the rest of the body. This spread occurs later in the course of the disease. The liver, bone, brain and other skin sites are common sites for the cancer to spread to.

The disease is usually diagnosed well into its course. Many patients who are diagnosed relatively early still end up with disease in other parts of their bodies.

How is Merkel Cell Carcinoma (MCC) Diagnosed?

Usually the patient visits the GP because of a rapidly growing non-tender mass, usually in sun exposed areas.

Prognosis of Merkel Cell Carcinoma (MCC)

The way that MCC behaves in people is not very well understood and seems to vary between individuals. However, the vast majority of Merkel cell tumours are very aggressive with local recurrence and early lymphatic spread being common.

For patients with lymphatic or systemic spread, the survival from MCC parallels that of malignant melanoma. Overall, 5-year survival is 30-60% in different series.

If the skin lesion is on the head or neck and there are no signs that the disease has spread, then there is a good chance that such a patient will do well. On the other hand, more than 75% of patients with disease that has spread will die from the cancer.

How is Merkel Cell Carcinoma (MCC) Treated?

Treatment is achieved via a combination of surgical excision, chemotherapy and radiotherapy.

Generally, surgery alone does not provide satisfactory results. However, better survival rates are achieved when surgery is combined with radiotherapy.

The surgical aspect usually involves cutting out the visible tumour with a wide margin around it, and removing lymph nodes to try and prevent the cancer from recurring. The radiotherapy is targeted towards the areas of the growth and also its surroundings in an attempt to prevent recurrence of the disease.

Merkel Cell Carcinoma (MCC) References

1. Veness MJP, Morgan CE, Gary J. Merkel cell carcinoma: A review of management. Current Opinion in Otolaryngology & Head & Neck Surgery. 2008;16(2): 170-4.
2. Feng H, Shuda M, Chang Y, Moore PS. Clonal integration of a polyomavirus in human Merkel cell carcinoma. Science. 2008; 319: 1096-102.
3. Ramzi S, Cotran VK, Tucker Collins, Robbins SL. Pathologic Basis of Disease. Seventh ed: W.B. Saunders Company; 2005.
4. Foschini MP, Eusebi V. Divergent differentiation in endocrine and nonendocrine tumors of the skin. Seminars in Diagnostic pathology. 2000; 17(2): 162-8.
5. Ratner D, Nelson BR, Brown MD, Johnson TM. Merkel cell carcinoma. Journal of the American Academy of Dermatologists. 1993; 29: 143-7.
6. Pectasides D, Pectasides M, Economopoulos T. Merkel cell cancer of the skin. Ann Oncol. 2006; 17(10): 1489-95.