A middle-aged man presented with bone pain at multiple sites due to tumour-induced osteomalacia. The underlying occult phosphaturic mesenchymal tumour was identified by octreotide scan 5 years after presentation and confirmed by computed tomography. Tumour resection resulted in normalisation of blood chemistry and bone densitometry. Clinico-radiologico-pathological correlation and ultrastructural studies of the tumour threw light on the pathogenesis and pathophysiology of this rare disease.