Clinical Impact of Somatostatin Receptor Scintigraphy in the Management of Tumor-induced Osteomalacia

OBJECTIVE: Tumor-induced osteomalacia (TIO) is a rare condition due to phosphate wasting secondary to the release of a phosphatonin, fibroblast growth factor-23. Attempts to identify the tumor by physical examination and/or conventional imaging are sometimes unrewarding. In such cases, somatostatin receptor scintigraphy with octreotide has been successfully proposed. METHODS: Two case reports and a review of the literature allow to demonstrate the diagnostic usefulness of octreotide and the therapeutic value of somatostatin. RESULTS: Octreotide studies were positive in 79% of 24 reported TIO, including our 2 cases. In one of our patients with incomplete removal of the tumor, octreotide therapy was unable to improve hypophosphatemia, despite a decrease in fibroblast growth factor-23 levels by 30%. Similar results were achieved in most of the reported cases. Surgical procedures were effective in these cases and resulted in complete clinical and biochemical recovery. CONCLUSION: We highlight the impact of somatostatin receptor evaluation in the management of TIO.