An unusual presentation of metastatic bone disease in a subject with Paget's disease of bone

Solid organ malignancies involving breast, prostate, and lung frequently metastasize to the skeleton. However, the occurrence of Paget's disease and metastatic bone disease in the same patient is uncommon. We report a case of a 63-year-old man who presented with back pain and a lump in the right breast. He was earlier diagnosed to have Paget's disease of bone based on characteristic skeletal radiological features,(99m)Tc methylene diphosphonate bone scan and elevated alkaline phosphatase, and treated with bisphosphonates, and his disease was in remission. Further evaluation revealed an underlying skeletal metastatic disease secondary to a breast malignancy. He underwent radical mastectomy with axillary node clearance, radiotherapy, and chemotherapy. In addition, he also received parenteral bisphosphonates for his skeletal metastatic bone disease.