FRIDAY, Dec. 22 (HealthDay News) -- Adding a new twist to the debate over the value of mistletoe as an alternative cancer treatment, British doctors are reporting the case of a patient whose consumption of an extract from the Christmas decoration led to a tumor-like growth.

An accompanying commentary suggests the case provides yet another reason to avoid using mistletoe as anything other than a holiday decoration. But an alternative medicine specialist points out that risks are inherent in conventional medicine, too.

While the plant itself is poisonous, mistletoe extracts have long been touted as an alternative cancer cure, especially in Europe and Germany. Extracts are typically given by injection and said to boost the immune system to fight tumors.

According to the National Institutes of Health (NIH), some mistletoe studies have suggested that it has value as a cancer treatment. However, the NIH -- which has launched its own study -- said the previous research has been flawed.

In the Dec. 23-30 issue of the British Medical Journal, doctors report about the case of a 61-year-old woman who reported a tumor-like mass in her abdomen after undergoing breast cancer treatment. She had previously suffered from lymphoma.

Doctors were mystified by the mass, until the patient revealed that she had been taking under-the-skin injections of a mistletoe extract as a treatment for lymphoma.

The doctors wrote that the mass appeared to be an inflammation caused by the mistletoe treatment. The report didn't say if the woman had any further problems.

In the commentary, Dr. Edzard Ernst, of the Universities of Exeter and Plymouth and a professor of complementary medicine, wrote that mistletoe produces many other side effects, including joint pain and kidney failure.

The claim that mistletoe injections have no serious risks "is therefore misleading," wrote Ernst, who added that "the costs of regular mistletoe injections are high."

Still, it's important to put the risks into context, said Dr. Adam Perlman, executive director of the Institute for Complementary and Alternative Medicine at the University of Medicine and Dentistry of New Jersey.

"I don't think the significance of this case report should be exaggerated," he said. "There is much that we do in conventional medicine that has limited evidence and potential for harm. The main issue here is less the risk of mistletoe and more the idea that the public needs to understand that 'alternative' medicine, in general, can have both potentially positive and negative consequences."

He added that the case points out that it's important for patients to be up front with doctors about alternative medications that they're taking.

More information

Learn more about mistletoe from the National Institutes of Health.