Oncogenic osteomalacia is a rare bone disorder caused by a tumor that secretes a hormone called fibroblast growth factor 23 (FGF23). This hormone causes the body to excrete too much phosphate, leading to a decrease in calcium and phosphate levels in the blood. This can cause softening of the bones, muscle weakness, and bone pain. Treatment typically involves removing the tumor and replacing the lost minerals with supplements.

The main symptom of oncogenic osteomalacia is bone pain, usually in the lower back, hips, and legs. Other symptoms may include muscle weakness, fatigue, and bone fractures. Other signs and symptoms may include:

• Loss of appetite

• Weight loss

• Nausea and vomiting

• Abdominal pain

• Bone deformities

• Softening of the bones

• Increased thirst and urination

• High levels of phosphate in the blood

• Low levels of calcium in the blood

• High levels of alkaline phosphatase in the blood

• High levels of parathyroid hormone in the blood

Oncogenic osteomalacia is caused by a tumor that secretes a hormone called fibroblast growth factor 23 (FGF23). This hormone interferes with the body's ability to absorb and use phosphorus, leading to a decrease in the amount of calcium in the bones. Other causes of oncogenic osteomalacia include certain types of cancer, such as renal cell carcinoma, and certain genetic disorders, such as hypophosphatemic rickets.

1. Vitamin D supplementation: Vitamin D supplementation is the mainstay of treatment for oncogenic osteomalacia. Vitamin D helps to increase calcium absorption from the gut and helps to restore normal calcium levels in the body.

2. Surgery: Surgery is often recommended to remove the tumor causing the oncogenic osteomalacia.

3. Bisphosphonates: Bisphosphonates are drugs that help to reduce bone loss and can be used to treat oncogenic osteomalacia.

4. Hormone therapy: Hormone therapy may be used to reduce the production of the hormone that is causing the oncogenic osteomalacia.

5. Radiation therapy: Radiation therapy may be used to shrink the tumor causing the oncogenic osteomalacia.

1. Exposure to certain chemicals, such as phthalates, which are used in plastics and other products.

2. Exposure to radiation, such as X-rays or radiation therapy.

3. Certain genetic conditions, such as multiple endocrine neoplasia type 1 (MEN1).

4. Certain medications, such as anticonvulsants, lithium, and phenytoin.

5. Certain tumors, such as those that produce fibroblast growth factor 23 (FGF23).

6. Certain endocrine disorders, such as hypoparathyroidism or hyperparathyroidism.

7. Certain metabolic disorders, such as renal tubular acidosis.

8. Certain infections, such as HIV or hepatitis C.

At this time, there is no known cure for oncogenic osteomalacia. Treatment typically involves medications to reduce the amount of phosphaturic hormone produced by the tumor, as well as medications to reduce pain and improve bone health. Additionally, surgery may be recommended to remove the tumor, if possible.