Summary

Tumour-induced osteomalacia is a paraneoplastic syndrome wherein bone is affected by a hormone from a tumour that causes renal phosphate wasting and hypophosphataemia. Here, we present the case of a 31-year-old man who has been suffering from generalised bone pains and a spine deformity that led to loss of height. Pertinent findings are low serum phosphorus, low vitamin D and decreased bone mineral density. These findings led to a diagnosis of osteomalacia. However, the finding of an oral mass raised some questions as to what role it plays in the patient's disease. It was suspected that the oral mass (fibroma) was producing a hormone that led to renal phosphate wasting, hypophosphataemia and then osteomalacia. This hypothesis was proven after surgical removal of the mass led to normalisation of the metabolic derangements and eventually led to a resolution of the bone pains.