Tumor-Induced Osteomalacia

What is tumor-induced osteomalacia?

Tumor-induced osteomalacia is a rare paraneoplastic syndrome that is characterized by bone pain, muscle weakness, and fractures. Affected individuals experience slow-growing lesions that form on the bone or soft tissue.

What are the symptoms of tumor-induced osteomalacia?

Characteristic symptoms include:

Fatigue
Bone pain
Muscle weakness
Fractures

What causes tumor-induced osteomalacia?

Tumors that form on the bones or soft tissue are the cause of this condition, as they produce an excess of FGF23. This protein is responsible for regulating phosphate and vitamin D, and when there is too much of it bone health is affected. This results in the characteristic symptoms.

How is tumor-induced osteomalacia diagnosed?

Doctors will begin with a clinical evaluation followed by various lab tests. Urine tests are primarily used to measure phosphate levels, among other things. A bone biopsy may also be necessary, along with imaging tests.

What are the treatments for tumor-induced osteomalacia?

The first treatment option is surgical removal of the tumors that cause symptoms. However, this is not always an option, and doctors will use phosphorus supplements in combination with calcitriol. This acts to regulate symptoms.