Maxillary tumour-induced osteomalacia

Tumour-induced osteomalacia (TIO) is a rare paraneoplastic form of renal phosphate wasting that results in severe hypophosphatemia, defective vitamin D metabolism, and osteomalacia. In the case reported here, maxillary TIO was not diagnosed for 6 years, although initial complaints were reported when the patient was 12 years old. Meanwhile she suffered from profound growth limitation, pain, weakness, and spontaneous multiple bone fractures, culminating in complete loss of ambulatory ability and severe limitation in daily activities. At age 18 years, she finally received an accurate diagnosis and definitive treatment was administered. She underwent a partial maxillectomy with complete removal of the tumour, resulting in a full cure. Shortly afterwards the patient regained the ability to walk, no longer needing the wheelchair to which she had been confined. This definitive diagnosis was based on three modalities: (1) fibroblast growth factor 23 analysis (high levels of the secreted hormone were found on the left side of the maxilla in the facial vein and pterygoid plexus, pinpointing the tumour location), (2) octreotide scan, and (3) 68Ga-DOTA-NOC-PET/CT. TIO removal via partial maxillectomy led to a complete reversal of this patient's health condition, restoring her ability to walk and function. The importance of prompt employment of these diagnostic modalities and the high level of clinical suspicion required in such cases are clear.