Merkel Cell Carcinoma Archives

Merkel cell carcinoma (MCC) is a rare but aggressive and lethal neuroendocrine carcinoma of the skin. Merkel cell carcinoma is more common in the elderly (age greater than 65) and mainly in Caucasians. MCC rarely occurs in patients with dark skin. Vast majority of these tumors present on sun exposed sites.

What causes Merkel Cell Carcinoma?

Excessive sunlight, prolonged ultraviolet radiation exposure, and photochemotherapy are all associated with an increased risk of MCC. Immunosupression due to solid organ transplant, HIV infection or chronic lymphocytic leukemia is also associated with merkel cell carcinoma.

Recently it has been suggested that a new virus named Merkel cell polyomavirus which was found in 8 out of 10 cases of merkel cell carcinoma may play role in etiology of Merkel cell carcinoma. [1]

Clinical Features:

Merkel cell carcinoma usually presents as firm, raised, reddish-blue or skin colored papule or nodule. Most initial lesions are less than 20 mm in diameter which grows rapidly with in 1-3 months. Ulceration of the lesion is rare. They re usually seen on sun exposed areas but not always. They are locally aggressive and later spread to distant lymph nodes in axilla, neck and groin.

Treatment for Merkel Cell Carcinoma

The current preferred treatment is surgical excision with sentinel lymph node biopsy followed by lymph node removal if biopsy comes positive. This may be followed by radiotherapy and this approach loco-regional control and disease free survival [2, 3]. Chemotherapy is not routinely recommended.

References:
1. Feng H, Shuda M, Chang Y et al. Clonal integration of a polyomavirus in human Merkel cell carcinoma. Science 2008; 319: 1096–100.
2. Mojica P, Smith D, Ellenhom JD. Adjuvant radiation therapy is associated with improved survival in Merkel cell carcinoma of the skin. J Clin Oncol 2007; 25:1043–7.
3. Eng TY, Boersma MG, Fuller CD et al. A comprehensive review of the treatment of Merkel cell carcinoma. Am J Clin Oncol 2007; 30: 624–36.

Merkel Cell Carcinoma also known as neuroendocrine carcinoma is a rare and very aggressive form of skin cancer. They are thought to arise from the uncontrolled growth of Merkel cells in the skin. MCC can be lethal with overall 2 years survival rate of 50-70%, So immediate aggressive treatment is required.

More then 95% of cases occur is a individual over 50 years of age. It is slightly common in men, although some authors reports women outnumber men by 4:1. MCC occurs more commonly in whites and is very rare in patients with dark skin. They commonly occurs in sun exposed areas.

What causes Merkel cell carcinoma?

It is not clear what exactly causes MCC, but potential risk factors are extensive sun exposure as 90% of cases occur in sun exposed areas (50% on head and neck and 40% on the extremities). Arsenic exposure and PUVA therapy may also be a potential risk factor. It has also been associated with immunosupression including HIV and organ transplant patients. Recently in 2008 a virus namely Merkel cell polyomavirus, was discovered which is thought to be frequently involved in causing MCC.

Sign and symptoms of Merkel cell carcinoma

Merkel cell carcinoma (MCC) occurs commonly face, head and neck. The lesions are raised , firm, painless, reddish-blue or flesh colored nodules or tumor usually seen on sun exposed areas. They are asymptomatic and may grow rapidly ,measuring between 0.5 to 2 cm or more. They are usually symptoms-less but if it has spread to other parts of body you may notice lymph node swelling and pain. If you notice any changes in size and color of the mole or bumps contact your doctor immediately.

Treatment of Merkel cell carcinoma

Various chemotherapeutic regimens have been purposed but none has proven to be better in improving survival rate. Treatment modalities are usually based on the stage of the disease. If the disease is in early stage and is localized in a skin, surgical excision followed by radiation therapy is recommended as a primary treatment. If the cancer has spread to the lymph nodes surgical excision with radio therapy and if needed systemic chemotherapy is administered.

For a patients with distant metastasis involving organ, radiation therapy with chemotherapy may be required. But, it is still unclear whether chemotherapy improves the survival rate in patients with Merkel cell carcinoma. The purpose of treatment of metastasis disease is to improve the quality of patient life by relieving symptoms like pain and help patients live comfortably.

The prognosis of a patients depends on the stage of disease at the time of diagnosis. If the cancer has not spread to lymph nodes, 5 year survival rate is more then 90%. If it has spread to lymph nodes, the 5 year survival rate is about 50%. The disease can reoccur in 50% of patients. It is important to keep in mind that these stats are based on the research of large group of patients and may not reflect each individual result or prognosis.