Paget’s disease (osteitis deformans) of bone is a focal skeletal disorder that can be mono- or polyostotic. Paget's disease might be asymptomatic as with normal biomarkers, or it can be symptomatic such as bony enlargement or deformity. The diagnosis can be made by laboratory findings and specific findings in radiology or radionuclide scan, and it is sometimes confirmed by bone biopsy.
In this report, we present the case of a 37-year-old man whose initial symptoms indicated sacroiliitis, which led to the suspicion of ankylosing spondylitis. Following other diagnostic evaluations and based on imaging features and bone biopsy, active Paget’s bone disease without abnormal biochemical markers was diagnosed. The laboratory diagnosis tests were normal. Other biomarkers including procollagen type I N-terminal propeptide (PINP), serum C-telopeptide (CTx), urinary N-telopeptide (NTx), and urinary hydroxyproline, are not routinely checked.
The patient also showed a coincidence of unilateral idiopathic gynecomastia. A single dose of 5 mg of zoledronic acid intravenously was prescribed, and the patient was followed for six months. Paget's bone disease can occur without any change in biochemical markers. In such cases, the response to treatment can be
controlled by improving the clinical picture or evaluating the correct imaging findings.