Musculoskeletal/CT/Skin Question Set 1

A 70-year-old male came for a routine health check to the outpatient department. He recently completely lost hearing in both ears and has occasional flare-ups of osteoarthritis in his hands and hips. He is a non-diabetic and hypertensive for the past 25 years. His brother recently died due to prostate cancer. His current blood pressure is 126/84 mmHg. Cholesterol levels are within normal limits. He is negative for PSA. Flexible sigmoidoscopy along with stool guaiac test are negative. Serum calcium, phosphorus concentrations and liver function test results are normal; however, ALP levels are increased by more than thrice the upper limit. Radiological tests are normal. What is the most likely diagnosis?