Tumour-induced or oncogenic osteomalacia (OOM) is a rare paraneoplastic syndrome characterized
by bone pain and muscle weakness. A biochemical profile consisting of normocalcaemia,
hypophosphataemia, phosphaturia, increased serum alkaline phosphatase and inappropriately
low serum levels of 1, 25-dihydroxyvitamin-D is diagnostic. OOM is usually caused by an osseous
or soft-tissue tumour of mesenchymal origin that secretes phosphaturic substances leading to
increased urinary phosphate wasting. These tumours are small and slow growing. The diagnosis
continues to be easily missed and when eventually made, localization of the tumour can be
difficult. We describe the case of a young man who presented with severe generalized pain
associated with muscle weakness. He was extensively investigated and eventually diagnosed to
have OOM 3 years after initial presentation. Specialized investigations were necessary to localize
the offending tumour.