(NEW YORK) -- Edward Williams first noticed a rash on his groin and legs after playing golf one day in the rain. He thought he might have been exposed to poison ivy or had an allergic reaction to chemicals on the wet grass. But he never suspected it was a sign of a rare pancreatic cancer.
The blistering sores spread to his arms, legs and even his eyes. The Waterport, N.Y., software developer went from doctor to doctor, trying every treatment from light therapy to topical ointments to oral steroids, but nothing worked.
"I had to hide it with long sleeves because I'm a business person," said Williams, who is now 54. "It was all over my face. I could literally shave only every other day, because it was so painful over the top of the blisters."
Williams lived with the debilitating rash for six years until a suspicious dermatologist from University of Rochester Medical Center in New York followed a hunch and diagnosed necrotic migratory erythema (NME).
Today, two years after surgery to remove the tumor on his pancreas, Williams is cancer-free.
"I feel like a new person," he told ABC News. "I just thought I had a rash and was getting older and didn't have quite the energy and stamina. I truly feel like a new person. And I am taking no medicine for absolutely anything."
And nearly as important, he is rash-free. "I am back to my baby skin," he said. "I feel very fortunate."
Pancreatic cancer is almost always fatal. But Williams had a glucagonoma, a rare, slow-growing tumor of the pancreas that results in extreme overproduction of the blood-glucose-raising hormone glucagon.
His doctors say that this serious condition can often be overlooked, and Williams' story is an example of how dermatologic conditions can be a "window" to the body, revealing more serious disorders.
"The skin has an amazing ability to tell the story of a person," said Dr. Brian Poligone, 40, an assistant professor at Rochester and an attending physician at its James P. Wilmot Cancer Center, who treated Williams.
"I know if they like the sun, or if they smoke, if they are scarred from war, if they are jaundiced with alcoholism -- or what color they painted their porch last weekend," he said. "It can give you a glimpse inside sometimes even telling you that they have cancer, before they know it."
Copyright 2012 ABC News Radio