What is Merkel Cell Carcinoma?

Ask most people and they will have a general idea of what skin cancer is. Skin cancer is divided into two groups - non-melanoma and melanoma.

Melanoma is considered the most aggressive form of skin cancer causing the most deaths from skin disease.

Non-melanoma skin cancer includes squamous cell, basal cell, actinic keratosis, kaposis sarcoma and merkel cell.

What is a Merkel Cell

The merkel cell was discovered over a hundred years ago and is responsible for the sensation of light touch in the hand. Manual dexterity of the hand would not be possible without these cells. Everything we do on a daily basis from tying shoe laces, buttoning shirts, threading needles, playing the piano to using a key to open a lock is possible because of merkel cells.

Merkel Cell Carcinoma

Merkel Cell Carcinoma (MCC) was discovered by Friedrich Merkel in 1875. It is a rare but deadly form of skin cancer affecting mostly the elderly or immunocompromised human population. It is estimated that there are 1500 new cases of MCC diagnosed each year. Treatment includes surgical removal of the tumor followed by chemotherapy and or radiation. Prognosis is poor as there is a high incidence of recurrence and metastasis.

Merkel Cell Polyomavirus (MCV)

Merkel Cell Polyomavirus is a common infection found in most older children and adults. It is thought to be spread by respiratory secretions. It is also thought to cause the majority of cases of MCC. This is caused by a mutation to the virus itself. In fact, more than 80% of the cases of MCC have the mutated virus present.

Symptoms

MCC usually first appears as a fast growing, painless, flesh colored or blueish nodule on the skin of the head and neck but can appear anywhere on the body even those areas not exposed to sunlight. It may bleed easily after mild trauma to the site such as after shaving or washing.

Diagnosis

Diagnosing skin cancer is done by physical exam and biopsy - removal of all or part of the suspected tissue for evaluation by a lab. Immunohistochemistry is essential in the definitive diagnosis and is highly accurate. Based on the results of the biopsy and the physical exam further tests may be ordered including CT scans and biopsy of the lymph nodes to determine extent, if any, of metastasis or spread of the cancer.

Treatment

Any treatment is based upon the diagnosis and extent of the disease. Generally, radical surgical resection or removal is the recommended primary treatment. Chemotherapy treatment is generally reserved for cases where the cancer has spread to other organs of the body. Radiation therapy sometimes follows removal of lymph nodes that are found to contain the cancer.

Prognosis

Due to the rarity of the disease it has been difficult for the medical community to compile information on the survival rate of persons with this form of cancer. However, it is noted that those without widespread disease and without lymph node involvement fair better than those with widespread disease and lymph node involvement. Most deaths occur within three years of diagnosis.

Conclusion

As with any skin cancer it is important to see your physician immediately if you notice any changes to your skin - especially if those changes are happening rapidly. This is not the time to take a wait and see approach. Due to the aggressive and deadly nature of this disease early diagnosis and treatment is the best chance for survival.

1. American Cancer Society - www.cancer.org
2. Pubmed
3. Science Daily - www.sciencedaily.com
4. www.merkelcell.org