Mr. Clinton is not the first president to be treated for basal cell skin cancer.
Lyndon B. Johnson concealed treatment for a basal cell skin cancer, which had no serious medical significance.
Unlike most other malignancies, basal cell skin cancers rarely kill or spread through the body to cause damage elsewhere.
Ronald Reagan had a basal cell skin cancer removed from his nose, and his vice president, George Bush, had a growth excised from his face.
President Lyndon B. Johnson did not want the public to know he had a basal cell skin cancer removed because disclosure would involve the word "cancer".
President Lyndon B. Johnson chose not to reveal that doctors had removed a basal cell skin cancer, a relatively minor condition, because disclosure would involve the word "cancer".
Having one melanoma slightly raises the risk of developing another melanoma, but an even greater chance of developing less serious basal cell skin cancers.
There is continuing debate as to how effective sunscreen is in reducing melanomas – the evidence is weaker than it is for preventing squamous cell skin cancer.
Follow-up examinations are common, experts say, because someone who has developed one basal cell skin carcinoma is prone to develop others.
Basal cell skin cancer is the most common and harmless type of cancer, affecting an estimated one million Americans a year, according to the Skin Cancer Foundation of New York.
In a report published online by the journal Science, they said that while they suspected that it caused Merkel cell skin cancer, more work was needed to prove it.
