A legal battle is brewing over the death of a 34-year-old British man who was told by three doctors that he was depressed, when he really had a tennis ball-sized brain tumor.

According to the Daily Mail, Chris Buckley's story of misdiagnosis, and possible malpractice, began in December 2011, when he developed a speech problem and sought medical attention at Robert Frew Surgery in Wickford, Essex.

His attending doctor, Oluwatoyin Ogunsanya, couldn't detect any other neurological symptoms, so he concluded that Buckley had depression. Buckley was prescribed the antidepressant citalopram, along with sleeping tablets, and recommended to seek counseling. Over the following month, Buckley's speech did not improve, but two more doctors — one from the same center, another recommended by the center — still believed that he had depression.

Eventually Buckley lost the use of his left arm, at which point, he visited an emergency room where his brain tumor was discovered. He died a few months later.

How did this tragedy happen? Is it so hard to tell the difference between a brain tumor and depression?

Nearly one in four with advanced glioma, a common form of brain tumor, were diagnosed with depression in one large study of 600 patients, and Buckley's account isn't the first mainstream story to highlight an issue with misdiagnosis. In 2007, reporter Bebe Bahnsen's described in Newsweek how a doctor failed to link her depression to a brain tumor, despite discovereing the growth early on with a MRI scan.

According a review by neurosurgeons Scott Litofsky and Andrew Resnick of the University of Missouri, patients with brain tumors "may initially present with psychiatric symptoms," but "these symptoms may be indistinguishable" from those in psychiatric patients without brain tumors.

They note that other clues can help make the distinction, including:

1. Psychiatric symptoms developing after the age of 40. The incidence of brain tumors is three times higher in people aged 35-64 relative to those between the ages of 20-34.

2. "A change in the patient's symptoms from his/her usual psychiatric symptoms also is suggestive of the possibility of a brain tumor." Such was the case for Bahnsen, whose depression suddenly became worse, which led to the discovery of her tumor

3. Patients who don't respond to depression treatment or those lacking a family history of psychiatric disease. This occurred with both Buckley and Bahnsen.

Litofsky and Resnick argue that any of these unusual features warrant further investigation with neuroimaging scanners.

It is hard to say if Buckley's death could have been prevented. As Ogunsanya told the Daily Mail, 'it is a big jump to say there was negligence. It was a very unusual presentation. When each one of us saw him there were no neurological problems, no headaches, no vomiting."

The UK's General Medical Council gave conflicting verdicts for the case, although Buckley's parents are now requesting a further investigation by the National Health Service and may pursue legal action, according to The Echo.

Source: Litofsky NS, Resnick AG. The relationships between depression and brain tumors. Journal of Neuro-oncology. 2009.