Merkel Cell Carcinoma?
A rare type of skin cancer, Merkel cell
carcinoma (MCC) often looks like a cyst, pimple, or stye. It can
even be mistaken for an insect bite. While this red to
violet-colored growth may look harmless, it is very aggressive. MCC
tends to spread quickly. Learning the signs and symptoms can help
you spot MCC early when it is most treatable.
Signs and Symptoms of Merkel Cell Carcinoma
Until recently, common signs and symptoms of MCC were not defined.
To identify common characteristics of MCC, a team of physicians
studied 195 patients diagnosed with MCC between 1980 and 2007. These
common characteristics emerged:
The AEIOUs of Merkel
Immune system may be
weakened. The person’s immune system can be
weakened from taking medication that helps prevent
organ rejection or a medical condition such as HIV.
Older than 50 years of
age. Most cases are diagnosed in people aged 50
and older. (90%)
exposure. MCC tends to develop on skin that has
received years of UV exposure. (81%) When the skin
is fair and has had years of UV exposure, this
percentage jumps to 98%.
Source: Journal of the American Academy of
Dermatology, 2008 Mar;58(3):375-81. Heath M, Jaimes
N, Lemos B et al. “Clinical characteristics of Merkel
cell carcinoma at diagnosis in 195 patients: the AEIOU
Where Merkel Cell Carcinoma is Most
Likely to Appear
Like other types of skin cancer, MCC is most likely to appear on
skin that has received years of sun exposure. About 50% of MCCs
occur on the head and neck. The eyelid is a common site as is the
rest of the skin around the eye.
MCC is not limited to the head and neck. It can appear anywhere on
the skin. A tumor may develop on an arm, leg, or buttock. MCC has
even been found inside the mouth and on the genitals.
Looking very much like a
bug bite, a biopsy revealed that this was Merkel cell
carcinoma on the patient’s shin.
cell carcinoma developed on the scalp of this
used with permission of the American Academy of
National Library of Dermatologic Teaching Slides)
Who is Most at Risk?
People 50 years of age or older who have fair skin and did not
protect their skin from the sun are most at risk. Research also
suggests that men are twice as likely as women to develop MCC.
It is rare for MCC to develop in someone under 50. If MCC develops
before then, the person usually has a weakened immune system.
Medication taken to prevent organ rejection after a transplant
operation weakens the immune system. The risk of MCC increases
10-fold in people taking this medication. Illnesses that weaken the
immune system such as HIV and chronic lymphocytic leukemia (a cancer
of the blood and bone marrow) also increase the risk. While a weak
immune system increases the risk, age and fair skin are still
greater risk factors.
Exposure to arsenic, infrared light, and certain medications also
increase the risk. One such medication is methoxsalen (meth-OX-a-len).
This medication is used in UV light therapy. Some patients who have
psoriasis or vitiligo receive methoxsalen during their PUVA therapy.
Rare . . . But Cases Increasing
Cases of MCC tripled between 1986 and 2001. About 1,500 cases
are now diagnosed in the United States each year, so MCC is still a
rare skin cancer. Researchers believe that the increase may be due
to the growing number of people over 50 years of age who had years
of unprotected sun exposure. As this population grows, cases of MCC
Early Treatment Offers Best Prognosis
Research suggests that early detection can improve the patient’s
prognosis. If the cancer has not spread, the patient may have a
greater than 90% chance of surviving.
If you believe you may have a growth on your skin that could be MCC
or any other type of skin cancer, see a dermatologist. These doctors
regularly diagnose and treat skin cancer.
Merkel Cell Carcinoma: What it
Appert DL, Rognigk RK. “Merkel Cell Carcinoma.” In: Nouri K, “Skin
Cancer.”China. McGraw Hill Medical; 2008. p. 181-94.
Jaimes N, Lemos B et al. “Clinical characteristics of Merkel
cell carcinoma at diagnosis in 195 patients: the AEIOU features.”
J Am Acad Dermatol 2008; 58:375-81.
Jaimes N. “Merkel Cell Carcinoma.” In: Wolff K, Goldsmith LA, Katz
SI, et al. editors. Fitzpatrick’s Dermatology in General Medicine,
7th ed. United States of America, McGraw Hill
Medical; 2008. p. 1087-94.
content solely developed by the American Academy of Dermatology
Merkel cell carcinoma is
even more aggressive than melanoma, a skin cancer that
claims one American life every 62 minutes. Early
detection and treatment of these skin cancers is