Tumor-induced osteomalacia (TIO) is a rare
paraneoplastic syndrome associated with
tumors secreting
fibroblast growth factor 23 that can be cured with complete surgical resection of the
tumor. However, when these
tumors are at difficult locations, less invasive modalities such as thermal ablation (TA) might be a good alternative. A 40-year-old woman was seen for a second opinion because of severe
hypophosphatemia with complaints of
fatigue,
myalgia, and
muscle weakness for which she needed IV
phosphate for 15 to 18 hours per day in addition to oral
alfacalcidol and
phosphate. Initial laboratory results revealed
hypophosphatemia (0.59 mmol/L [1.83 mg/dL]; reference range, 0.90-1.50 mmol/L [8.40-10.2 mg/dL]), increased
fibroblast growth factor 23 levels (137 RU/mL; reference range, <125 RU/mL), and a reduced
TmP-GFR (0.47 mmol/L; reference range, 0.8-1.4 mmol/L).
Gallium-positron emission tomography/computed tomography (CT) showed moderately increased uptake at thoracic vertebra (Th) 8 and mildly increased uptake at Th7, suggestive of TIO. Complete
tumor removal would have required resection of at least 1 vertebral body. Therefore, CT-guided TA was performed at Th8. No complications were observed, and in the months
after, treatment with IV
phosphate could be discontinued, indicating a satisfying result from the procedure. This extreme TIO case demonstrates that CT-guided TA can be an alternative to extensive or risky classical surgery.