A Rare Case of Tumor-Induced Osteomalacia Due to Mesenchymal Tumor at Foramen Magnum Diagnosed Preoperatively on 68Ga DOTATATE PET/CT

Abstract A 42-year-old man, a known case of FGF23-dependent hypophosphatemia, underwent 68 Ga- DOTATATE PET-CT, which showed a somatostatin receptor–expressing lesion in the left arch of foramen magnum that was correlated on MRI as a soft tissue lesion measuring 2.2 × 1.3 cm. It was excised and histopathologically confirmed as phosphaturic mesenchymal tumor. Postoperatively, patient improved clinically and recovered from hypophosphatemia completely. A distinct focal uptake in a 68 Ga- DOTATATE PET-CT in a patient with tumor-induced osteomalacia needs extensive workup and high degree of suspicion to rule out mesenchymal tumor at nonconventional location as seen in the present case.