A 64-year-old woman in Portugal learned she had colon cancer after her first-ever colonoscopy. Twelve weeks later, surgeons removed the section of bowel where the tumor had been marked with tattoo ink. The ink was there. The cancer was not.
Her doctors at the Viseu Dão-Lafões Local Health Unit then did something unusual. Before accepting that the tumor had disappeared on its own, they treated the case as a possible medical error and retraced every step, ending with a DNA comparison between her original biopsy and the removed colon. The profiles matched.
