Introduction: Tumor induced osteomalacia (TIO) is a rare paraneoplastic syndrome characterized by an excess of Fibroblast Growth Factor (FGF)-23 leading to chronic hypophosphatemia and hyperphosphaturia. The diagnosis is challenging, therefore, treatment is often delayed.
Case Description: We present a case of R.U., a 36 year old female who was referred to our section due to multiple bone pains. Three years ago, she presented with pain on ambulation which later on progressed to multiple bone pains and generalized muscle weakness. She was initially managed as a case of multiple metastasis from an unknown primary due to the whole body scan showing multiple radiotracer uptake in the mandibular, rib, shoulders, thoracic, pelvic area. However, her workup for malignancy and multiple myeloma were negative. Pertinent findings included a persistently low phosphorus (0.5?0.7 mmol/l NV (0.81?1.45), normal calcium, elevated alkaline phosphatase. The Fractional Tubular Reabsorption of Phosphorus (TmP/GFR) revealed low for her age (0.589 NV (0.95?1.42)) signifying a phosphorus renal wasting condition. TIO was considered due to the biochemical and clinical profile of the patient. Since tumors take up octreotide, a technetium-99?m octreotide scintigraphy was done and revealed uptake in the right acetabular area. MRI of the pelvis showed a 2 cm tumor growth in the same area consistent with the octreotide scan. The definitive management of this condition consists of wide excision of the tumor. However, when surgical management is not feasible, medical management consists of phosphorus and calcitriol tablets.
Conclusion: The diagnosis of TIO always be included in patients presenting with bone pain and persistently low phosphorus. Early identification and excision of tumor could prevent severe disability and death.
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