Oncogenic osteomalacia, or tumor-induced osteomalacia, is a rare, serious paraneoplastic syndrome. It is predominantly driven by a small, benign mesenchymal tumor. The disease is readily prompted by the clinical features such as hyperphosphaturia, hypophosphatemia, low serum vitamin D3 levels, elevated serum fibroblast growth factor 23 levels, and osteomalacia. However, the causative tumor is frequently hidden in an unusual anatomical site and often goes undetected by conventional imaging, such as computed tomography (CT), while a permanent cure of the disease will only rely on exact localization and completely removal of the tumor.