Oncogenic osteomalacia caused by phosphaturic mesenchymal tumours in the proximal and shaft of the tibia: a case report.

Oncogenic osteomalacia is caused by a small mesenchymal tumour characterised by phosphaturia, hypophosphatemia, decreased serum vitamin D3 level, and osteomalacia. Phosphaturic mesenchymal tumour of the mixed connective tissue type (PMTMCT) is the commonest subtype and usually involves a single site. We report a case of PMTMCT involving the left proximal and shaft of the tibia in a 42-year-old man.