Oncogenic osteomalacia, you say? better start looking then - a case report

ABSTRACT

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.