Merkel cell cancer, also called Merkel cell carcinoma or trabecular cancer, is a rare and highly aggressive cancer where malignant cancer cells develop on or just beneath the skin and in hair follicles. This cancer is a type of neuroendocrine tumor, like small cell lung cancer. Merkel cell carcinoma is the most serious form of skin cancer. One third to one half of all patients with Merkel cell cancer eventually die of the disease. Merkel cells are large oval cells found in the skin of vertebrates. ... Cancer is a class of diseases or disorders characterized by uncontrolled division of cells and the ability of these cells to invade other tissues, either by direct growth into adjacent tissue through invasion or by implantation into distant sites by metastasis. ... In medicine, malignant is a clinical term that is used to describe a clinical course that progresses rapidly to death. ... For alternate meanings see skin (disambiguation). ... A hair follicle is part of the skin that grows hair by packing old cells together. ... Neuroendocrine tumors, or more properly gastro-entero-pancreatic or gastroenteropancreatic neuroendocrine tumors (GEP-NETs), are cancers of the interface between the endocrine (hormonal) system and the nervous system. ...

It occurs most often on the face, head, and neck. It usually appears as firm, painless, nodules, or tumors. These flesh-colored, red, or blue tumors vary in size from 5 mm (less than a quarter of an inch) to more than 5cm (2 inches). The tumor grows rapidly. About half of all Merkel cell cancers occur on the sun-exposed areas of the head and neck, while one-third begin on the legs, and 15% occur on the arms. The cancer may also begin on other parts of the body, such as the trunk. A nodule describes an aggregation of similar cells or particles in a number of scientific fields: In medicine it refers to a small aggregation of cells. ... Tumor (American English) or tumour (British English) originally means swelling, and is sometimes still used with that meaning. ...

From initial onset, Merkel cell cancer metastasizes quickly and spreads to other parts of the body, tending towards the regional lymph nodes. The tumor tends to invade underlying subcutaneous fat, fascia, and muscle. It can also metastasize to the liver, lungs, brain or bones. Metastasis (Greek: change of the state) is the spread of cancer from its primary site to other places in the body. ... Lymph nodes are components of the lymphatic system. ... Adipose tissue is an anatomical term for loose connective tissue composed of adipocytes. ... Fascia is specialized connective tissue layer which surrounds muscles, bones, and joints, providing support and protection and giving structure to the body. ... A top-down view of skeletal muscle Muscle (from Latin musculus little mouse, referring to muscles like the biceps which pop up as though a mouse were scurrying about under the skin [1]) is contractile tissue of the body and is derived from the mesodermal layer of embryonic germ cells. ... The liver is the largest internal organ of the human body. ... The heart and lungs (from an older edition of Grays Anatomy) The lung is an organ belonging to the respiratory system and interfacing to the circulatory system of air-breathing vertebrates. ... Comparative brain sizes In animals, the brain, or encephalon (Greek for in the head), is the control center of the central nervous system. ... Grays illustration of a human femur, a typically recognized bone. ...

Epidemiology

This type of cancer occurs mostly in -- though not restricted to -- whites between 60 and 80 years of age. It occurs about twice as often in males as in females. There are roughly 1000 cases a year in the United States. Merkel cell cancer can be mistaken for another cancer like basal cell carcinoma, squamous cell carcinoma, malignant melanoma, lymphoma, small cell carcinoma or may appear to be a benign cyst. Researchers believe that exposure to sunlight or ultraviolet light may increase a person’s risk of this disease. This article does not cite its references or sources. ... Basal cell carcinoma (BCC) is the most common skin cancer. ... In medicine, squamous cell carcinoma is a form of cancer of the carcinoma type that may occur in many different organs, including the skin, the esophagus, the lungs, and the cervix. ... Melanoma is a malignant tumor of melanocytes. ... Lymphoma is a variety of cancer that originates in the lymphatic system. ... Small cell carcinoma is a type of carcinoma usually associated with the lung, though it can be associated with other topographies, such as in cervical cancer. ... This is an article about cysts in the body. ... Prism splitting light Sunlight in the broad sense is the total spectrum of electromagnetic radiation given off by the Sun. ... Note: Ultraviolet is also the name of a 1998 UK television miniseries about vampires. ...

Immune suppression can profoundly increase one's risk of developing Merkel cell cancer. According to a recent study in the Lancet, Merkel cell carcinoma occurs 13.4 times more often in people with advanced HIV as compared to the general population. Solid organ transplant recipients have similarly increased risk. Immunosuppression is the medical suppression of the immune system. ... Human immunodeficiency virus (commonly known as HIV, and formerly known as HTLV-III and lymphadenopathy-associated virus[1][2]) is a retrovirus that is the cause of the disease known as AIDS (Acquired Immunodeficiency Syndrome), a syndrome where the immune system begins to fail, leading to many life-threatening opportunistic...

Treatment

Because Merkel cell cancer is uncommon and is difficult to diagnose, patients may want a second opinion about the diagnosis and treatment plan before starting treatment. However, early diagnosis and treatment of Merkel cell cancer are important factors in decreasing the chance of its spread. It is difficult to cure once it has spread.

Surgery

Surgery is the usual treatment for Merkel cell cancer. The tumor is removed along with a border of healthy tissue surrounding it. Nearby, or regional, lymph nodes are often removed because they may contain cancer cells. Sometimes the doctor does a sentinel lymph node biopsy. In this procedure, the doctor injects a dye or radioactive substance near the tumor. This material flows into the first lymph nodes where cancer is likely to spread (the sentinel nodes). These nodes are then removed and checked for cancer cells. Cancer is a class of diseases or disorders characterized by uncontrolled division of cells and the ability of these cells to invade other tissues, either by direct growth into adjacent tissue through invasion or by implantation into distant sites by metastasis. ... Tumor (American English) or tumour (British English) originally means swelling, and is sometimes still used with that meaning. ... The lymphatic system is a complex network of lymphoid organs, lymph nodes, lymph ducts, and lymph vessels that produce and transport lymph fluid from tissues to the circulatory system. ... A biopsy (in Greek: bios = life and opsy = look/appearance) is a medical test involving the removal of cells or tissues for examination. ...

Radiation & Chemotherapy

Adjuvant radiotherapy has been shown to be effective in reducing recurrence and increasing five year survival of patients with Merkel Cell Carcinoma. Patients who present with no metastases and a negative sentinel lymph node biopsy have a good prognosis when treated with surgery and radiotherapy - approximately 90% survival at five years. In medicine, adjuvants are agents which modify the effect of other agents while having few if any direct effects when given by themselves. ... Radiation therapy (or radiotherapy) is the medical use of ionizing radiation as part of cancer treatment to control malignant cells (not to be confused with radiology, the use of radiation in medical imaging and diagnosis). ...

Merkel cell cancer that has metastasized may respond to treatment with chemotherapy and/or radiation. This therapy usually does not cure the disease, but can be effective in shrinking the tumor if the tumor is too large to be removed, or is located in a place where removal would be difficult or dangerous.

See also

• Cancer
• Carcinogenesis

Cancer is a class of diseases or disorders characterized by uncontrolled division of cells and the ability of these cells to invade other tissues, either by direct growth into adjacent tissue through invasion or by implantation into distant sites by metastasis. ... Cancers are caused by a series of mutations. ...

External links

• In-depth medical article on EMedicine
• National Cancer Institute listing for Merkel cell cancer
• Merkel Cell Cancer Discussion Group. Where you can openly share as a patient with MCC, or a family member supporting someone with MCC.
• WWW.Merkelcell.org--Information for Patients & Their Physicians
• Información general sobre el carcinoma de células de Merkel - Information About Merkel Cell Cancer in Spanish

• Pathology of Merkel Cell Carcinoma