A Case Report of Hypophosphatemia Leading to the Diagnosis of Mesothelioma

Hypophosphatemia can be commonly encountered as an electrolyte imbalance and is defined as a value less than 0.8 mmol/l (2.5 mg/dl). It can be an incidental finding, but it is not uncommon to see it presenting with varied symptoms. It is good to have a clear diagnostic approach to this so adequate treatment can be instated. We present a 66-year-old gentleman who presented with hypophosphatemia. Investigations confirmed renal phosphate wasting secondary to fibroblast growth factor-23 (FGF-23). Imaging showed right pleural effusion, and pleural biopsy confirmed malignant mesothelioma. This may just be an association rather than the cause of his hypophosphatemia. It does however highlight the importance of further investigations for patients with tumor-induced osteomalacia.