A 69-year-old female complained of intermittent left hip pain for the past 3 years. Biochemical tests revealed normal serum calcium and phosphorus with markedly raised alkaline phosphatase. MRI of the hip revealed extensive marrow signal abnormalities at the left pelvic bone, while CT of the thorax revealed a spiculated lung nodule at the left lower lung lobe. In order to diagnose either primary, metastatic bone tumour or Paget's disease of the bone (PDB), an open biopsy of the left iliac bone was performed. The histopathology of bone biopsy of the left iliac bone was consistent with PDB. A CT guided biopsy of the lung mass done later revealed adenocarcinoma of the lung. She had 18F-FDG PETCECT Scan for staging evaluation and result was suggestive of new bony metastases. Patient was started on IV Zoledronic acid for treatment of the PDB. In view of the stage 4 lung adenocarcinoma with bony metastases, patient was scheduled for palliative chemotherapy.