Abstract 102: Case series of tumor induced osteomalacia

Tumor induced osteomalacia (TIO) is a rare paraneoplastic syndrome characterised by small mesenchymal tumors secreting phosphotonins resulting in musculoskeletal pains, proximal myopathy and pathological fractures. Aims and Objectives: To describe clinical, biochemical characteristics and outcomes among TIO patients at our institute. Results: Eight patients were included in this study (75% female). The mean age was 36.5, mean duration of illness was 5.25 years. All of them presented with musculoskeletal pains and proximal myopathy. Pathological fractures were seen in 6/8. Two of them were wheel chair bound and rest walked with support. Mean serum calcium was 8.78 mg/dl with, phosphate of 1.36 mg/dl, vitamin D of 39.41 ng/ml, PTH of 125.95 pg/dl, ALP of 353 U/L and TmP/GFR of 1.22 mg/dl. Mean pre-op FGF23 levels was 251 RU/ml (2/8 patients). Six patients underwent 68Ga DOTONAC PET CT, of which only 3 showed metabolically active lesion and underwent excision and showed improved functional status. Conclusion: Our study shows that 50% of the patients did not have localization of tumor on functional scan at presentation. This requires long term follow-up with repeated scans.