Oncogenic osteomalacia

Oncogenic osteomalacia is a condition where a small tumor causes a weakening of the bones. This happens because the tumor releases a substance called fibroblast growth factor 23 (FGF23), which stops the kidneys from absorbing enough phosphate. Phosphate is essential for strong bones, so its low levels in the blood lead to soft and weak bones, a state known as osteomalacia. In addition to bone weakening, biochemical tests show high levels of phosphate in the urine (hyperphosphaturia) and low levels in the blood (hypophosphatemia). Most tumors associated with this condition are slow-growing and benign. They are often found in the skin, muscles, bones of the extremities, or even in the paranasal sinuses. The condition is usually diagnosed when these clinical features are present and a tumor is identified through imaging studies.

People with this condition typically experience weakening of the bones, which may lead to bone pain, fractures, or muscle weakness. Laboratory tests often reveal low blood phosphate levels and high phosphate levels in the urine.

This condition is caused by a tumor that releases fibroblast growth factor 23 (FGF23). FGF23 interferes with the kidneys' ability to reabsorb phosphate, leading to low phosphate levels in the blood. While the exact reason the tumors develop is not known, most of these tumors are benign and tend to be small and slow-growing.

The primary treatment for oncogenic osteomalacia is the surgical removal of the tumor. Once the tumor is removed, symptoms including the weakening of bones typically improve.

The outlook for people with this condition is generally good if the tumor is successfully removed. Since most tumors are benign, the symptoms, including bone weakness, usually resolve after treatment. However, if the tumor is not found or removed, symptoms may continue.

Information about current research and future directions is currently limited for this condition.