An unidentified 32-year-old California woman, who was diagnosed with cervical cancer, underwent a PET/CT fusion scan in November 2012 so that doctors could check to see if her cancer had spread.
The imaging from the sophisticated scan, which includes a shot of a radioactive tracer, showed bright areas in her pelvic area lymph nodes, leading doctors to believe the cancer had spread there, reports Live Science.
The mom of four underwent extensive surgery to remove her pelvic lymph nodes, uterus, cervix and fallopian tubes, noted the New York Daily News.
However, it was not until after her surgery that doctors discovered via microscope that the "cancer" in the woman's pelvic lymph nodes was actually tattoo ink.
The patient had several tattoos on her legs.
Dr. Ramez Eskander, of the University of California, Irvine Medical Center, treated the woman and co-authored a report about the incident in the medical journal Obstetrics and Gynecology this week.
"Those lymph nodes that were lighting up brightly on the PET scan were doing so because of the tattoo pigment that was in the lymph nodes," Eskander said.
"Findings of possible metastatic disease on PET scans can certainly change management. We want to make sure that people understand that these false positives could potentially arise in patients that have tattoos," Eskander added.
A small amount of cancer was found in one of the woman's pelvic lymph nodes, but those cancer cells didn't show up on the scan.
The patient didn't experience any post-operative complications and has not had a rebound of the cancer, according to Eskander.