TIO: The bone-breaking tumor

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Physical therapy to help with his degenerative disc. Steroid injections to treat his psoriatic arthritis.

One young high school teacher went from doctor to doctor and diagnosis to diagnosis to find out why his bones were breaking but left with more pain than answers.

This is how he got back on his feet.

Two years ago, David Covington didn't think his back pain and general weakness would turn into him needing a cane at 27. He even had a hard time with household chores.

"I couldn't get the lawn mower started and it was just a pull and I wasn't strong enough to pull it on," Covington said.

Doctors did a full body scan on him and found he had several stress fractures throughout his body.

"That was kind of where I really felt that, 'Oh maybe this is something more serious than just back pain,'" he recalled.

After two orthopedists, a rheumatologist and months of treatments, Covington's condition worsened and he became so weak that he was falling.

Then an endocrinologist at Vanderbilt University said a tumor in his brain may be the culprit.

"A rare problem called TIO, which stands for tumor-induced osteomalacia, so tumors causing breakdown of bone," Dr. Reid Thompson explained.

Covington was referred to Thompson, a neurosurgeon, who at first thought it was a benign tumor.

"If you ask most neurosurgeons who specialize in brain tumors what it is that you have, they would say it's a benign tumor, nothing to worry about," Thompson said.

But a quick search about TIO changed his mind.

"We really had to do that operation, because it was a chance to actually cure him of this disease which was ravishing his body," Thompson said.

After the surgery and about a month of physical therapy, Covington felt back to normal.

"It would take about five minutes to get from my car to the front door," he said. "Now it takes about 15 seconds."

And two months after surgery, Covington was back in his classroom teaching, pain-free.

Doctors say Covington's case of TIO was even more rare because of its location. Most of those tumors are normally found in the hands, feet or nasal cavities.

MEDICAL BREAKTHROUGHS
RESEARCH SUMMARY
TOPIC: TIO - The Bone-Breaking Tumor
REPORT: MB #4681

BACKGROUND: Meningiomas are the most common brain tumors. They typically form on the membrane covering the brain and they occur more often in women than in men. The tumors are often slow-growing and as many as 90% are benign, or not cancerous. Most of the time, meningiomas cause no symptoms and require no immediate treatment, thus no need to remove them. That's why when patient David Covington came to neurosurgeon Dr. Reid Thompson at Vanderbilt University with several bone fractures and body weakness, Dr. Thompson believed David's tumor to be a meningioma and could not possibility explain his bone-breaking symptoms until he did further research. (Source: https://www.webmd.com/cancer/brain-cancer/meningioma-causes-symptoms-treatment#1)

TIO: Tumor-induced osteomalacia, or TIO, is a rare tumor that releases a growth factor that can cause breakdown of bone. The condition is characterized by bone pain, bone fractures, and muscle weakness. The tumor is caused by overproduction of fibroblast growth factor 23 (FGF23). Fibroblast Growth Factor 23 is involved in phosphate absorption, which plays an important role in bone health. TIO tumors are often located in the extremities, such as the hands or feet. However, they can be found in other locations like in David's case where it was found in his brain. They are unlikely to spread, but they may be difficult to locate on an x-ray or MRI. The diagnosis is usually confirmed by a blood test for Fibroblast Growth Factor 23. (Sources: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5633085/, https://www.ultragenyx.com/patients/tio/)

TREATMENT: Complete removal of the tumor is the most effective treatment and can cure the patient of the symptoms of TIO. If the tumor is in a location where it may be impossible to remove, medical therapy with phosphate and active vitamin D is usually successful in healing the osteomalacia and reducing symptoms. However, due to the frequent dosing regimen and side effects, compliance to treatment is often poor. Currently, new treatment options are being developed for those patients with TIO whose tumor may be inoperable. Some of the options include image-guided tumor ablation and medical treatment with the antiFGF23 monoclonal antibody KRN23 or anti FGFR medications. (Source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5633085/)