Merkel Cell Carcinoma

Merkel cells are found in the outermost layer of the skin and are important for light touch sensation. As such, they are commonly found in sensitive skin areas, like fingertips, where they are connected to nerve endings that transmit feelings of sensation. Though uncommon, these cells can become malignant and form MCC.

It is unclear what exactly causes MCC, although it does begin in the epidermis (top layer of the skin). A common virus (Merkel cell polyomavirus) that lives on the skin may be involved in this process, but since the virus is common, it is likely there are other risk factors involved in the development of this cancer.

Long-term sun exposure, including ultraviolet (UV) light from tanning beds, light skin color, a weakened immune system, a history of other skin cancers, biological males, and being over fifty years old can all increase the risk of developing MCC.

MCC is a rare skin cancer but diagnosed cases have been increasing over the past decade. Each year, about 2,000 cases of MCC are diagnosed in the U.S. and men are nearly twice as likely to develop it relative to women. MCC is the second most common cause of skin cancer death in the United States after melanoma but with early detection, MCC can be treated successfully.

If you notice a freckle, mole, bump, or a “cyst” that begins to change in size or color, grow quickly, or bleed after normal washing or shaving, it is important to be evaluated by a board-certified dermatologist. MCC can be mistaken for other types of cancer or even benign cysts, which is why being seen by an expert is crucial for diagnosis.

By reducing exposure to UV rays and sunlight, especially between 10 a.m. and 4 p.m., the risk of MCC can be lowered. Taking sun-protective measures, including wearing sunglasses, a wide brim hat, and tightly-woven clothing, are some of the most important ways to reduce sun exposure. Wearing sunscreen with SPF 30 and above, containing physical blockers like zinc oxide or titanium, also reduces the risk of developing MCC. Finally, it is important to make an appointment to be seen regularly by a board certified dermatologist to ensure early diagnosis and prevention.