Oncogenic osteomalacia -- hypophosphataemic spectrum from "benignancy" to "malignancy"

Though case reports and case series about oncogenic osteomalacia due to benign mesenchymal tumours and much more rarely, secondary to malignant ones exist in the literature, there has not been any series reported from a single department spanning the gamut of causes from benign to malignant. We present 3 patients who were seen at the department of endocrinology of our hospital between 2010 and 2012 with hypophosphataemia and severe skeletal complications. All of them were found to have oncogenic osteomalacia otherwise known as tumour induced osteomalacia (TIO) - a paraneoplastic syndrome characterised by renal phosphate wasting and severe hypophosphataemia. The implicating tumours in our patients ranged from a subcutaneous mesenchymal tumour in the heel to a mixed connective tissue variant within the nasal cavity to metastatic prostate cancer. All our patients had protracted periods before the diagnosis was made, during which time the burden of their metabolic and skeletal pathology had increased. A timely recognition of the clinical features and biochemical findings of this rare but potentially debilitating disease is critical. Physicians should be cognizant of the presence of the disease and its localising and treatment strategies.