When doctors diagnosed a 60-year-old patient suffering from abdominal pain with cancer, she questioned the diagnosis—and her skepticism might've saved her life, W. Robert Graham, a retired physician who later treated the patient, writes for MedPage Today.

Cheat sheets: Evidence-based medicine 101

She rejected life-threatening diagnosis

The patient, a refugee from El Salvador, first came to the ED with abdominal pain.

A team of doctors and medical students attended to the woman, and a CT scan of her abdomen showed a "mass" in her liver. A biopsy of the mass was sent to pathology, where residents and an "expert pathologist" found abnormal cells in the biopsy, according to Graham.

But while the CT scan and the biopsy indicated cancer, a blood test for liver cancer called an alpha-fetoprotein (AFP) test showed the patients AFP was not elevated, suggesting she did not have liver cancer. But since the team detected liver cancer cells in the biopsy, "they assumed she had cancer" and told the woman she would need chemotherapy, Graham writes.

When she heard the news, the patient, who was from the countryside, disagreed. "She told the doctors that she didn't have cancer," Graham writes.

However, the medical team stood by their diagnosis and told her that if she left the hospital without being treated, she would die. In response, "She told them she wanted to leave," Graham writes. "She said that she would take her chances."

A year later, a new diagnosis proved her right

A year later, the woman returned to the ED complaining of abdominal pain and weight loss. That's when she saw Graham. When he reviewed her records, he learned about her previous ED visit. But when he looked at the CT scan that she'd undergone, "what [he] saw surprised [him]:" The mass did not look like cancer, Graham writes. "It was a mass that was primarily a cyst."

Graham reviewed the woman's records further and saw that she had no risk factors for liver cancer. She "did not have chronic hepatitis, and she did not abuse alcohol. Therefore, there was no reason why she would have primary liver cancer," he writes.

The woman's records and her cyst reminded Graham of a different diagnosis, amebiasis, which occurs when amoebas, parasites found in contaminated water, get inside the body. The amoebas can travel from the intestine to the liver and create a cyst.

A test of the patient's stool confirmed she had amebiasis, which could've resulted from drinking from ponds and streams in the countryside. With the proper treatment, the woman's condition improved.

The woman was right, Graham writes, she "never had cancer." In fact, if she had undergone chemotherapy at the doctors' recommendation, "she probably would have died," Graham writes. He explains, "Treating a patient with chemo when they have a serious underlying infection would likely cause that infection to kill." However, "had she died in that manner, the doctors would have said that she died from liver cancer," Graham writes. "No one would have known the truth."

Why errors like this aren't unheard of

This was not the first time Graham witnessed a diagnostic error that stemmed in part by findings from imaging or other medical technology. Errors like these, Graham contends, "happen because doctors and the public are led to believe that the CT scan or MRI give definitive answers all the time." However, he writes, "Sometimes they give those answers, sometimes they don't."

Graham adds that issues like this are fueled in part by "threats of lawsuits" that affect the culture of medicine. For instance, a radiologist could be sued if they miss a cancer diagnosis that shows up on a scan, which makes radiologists more likely to "over-call a mass seen on CT," he writes.

Further, the summary of findings of the CT scan introduced a bias into the diagnostic process, Graham argues. When the tissue for the biopsy was sent to the pathology department, the summary of the case said the mass was "consistent with hepatocellular carcinoma." This could have caused the pathologist to assume she was looking for liver cancer.

The fact that the patient "had the strength to stand against the doctors is remarkable," Graham writes (Graham, MedPage Today, 2/24).