Tumour-induced osteomalacia: a diagnostic conundrum

Phosphaturic mesenchymal tumours (PMTs) are rare fibroblast growth factor-23 producing lesions presenting clinically as cases of osteomalacia. Non-specific symptoms and a varied histological appearance often lead to misdiagnosis, delayed treatment and prolonged morbidity for the patient. We report a case of a patient in his late forties presenting with generalised body ache, weakness and difficulty in walking for 3 years. Biochemical investigations revealed an increased renal phosphate wasting, with functional imaging showing a somatostatin receptor-expressing lesion in the distal epiphysis of the left tibia. A CT scan was done to precisely locate the tumour which was then resected en bloc. The patient was managed postoperatively with oral phosphate and vitamin D supplementation, which saw him recover completely at 1-year follow-up. Guidelines for diagnosis and treatment of PMTs need to be established to streamline the management of this condition.