Williams didn't display any of the other "classic" symptoms of NME, which made it harder to immediately diagnose, according to Poligone.
"There were some clues, but in the end, things threw you off," said Poligone.
A poison ivy rash can also be present in the groin area, but it disappears with time.
"He had this red rash on his face and around his eyebrows and mouth and legs -- sort of one or two centimeters, red-orange plaques," he said. "At first, you consider a few things, but you don't want to do a lot of testing. As time goes on, the good doctor has to expand that differentiation and starting thinking zebra instead of horse."
Poligone knew "something was missing" and wondered if Williams could have NME because of the rash in the groin area, a telltale sign.
"It's the only case I had ever seen, though I had read about it in the textbooks," he said.
He consulted a mentor, Dr. Peter Heald, professor emeritus of dermatology at Yale, who suggested his former student was on the right track.
Poligone ordered a glucagon test and an insulin test. Both came back abnormal. He ordered a CT scan to look at Williams' pancreas, which pinpointed a tumor.
When Williams was finally diagnosed in December 2010, he Googled pancreatic tumor. "The stories weren't good. None of them had good outcomes."
With a wife and two adult daughters, aged 28 and 30, he said he thought, "O.K. How many months do I have to live? It was tough, especially during the holiday season."
Dr. Luke Schoeniger, an associate professor of surgery and oncology at Rochester, performed the operation to remove the tumor. Follow-up CT scans have shown no recurrence of the cancer.
Most pancreatic cancers carry a death sentence because they are usually so advanced before they are detected, according to Poligone.
It took six weeks to recover from surgery, but Williams began taking short walks and feeling better.
"Now when I get up in the morning, I appreciate I don't have the rash," he said. Nor the cancer, thanks to his diligent dermatologist.
"Dr. Poligone's persistence to solve my case saved my life," said Williams, who has been lucky enough to see his daughter Rebecca get married this year and give him a grandson.
His doctor is thrilled with the outcome of Williams' mystery rash.
"This is the reason we all want to go to medical school -- to get to do this," said Poligone. "It's really a great feeling to have done some good."