Asymptomatic Paget's disease of bone in a 62-year-old Nigerian man: three years post-alendronate therapy

Paget's disease is a chronic and progressive disorder of bone characterized by focal areas of excessive osteoclastic resorption accompanied by a secondary increase in the osteoblastic activity. Paget's disease of bone (PBD) is a rare endocrine disease especially among Africans and Asians. Hence the detection of a case in a middle-aged Nigerian is of interest. We present the case of a 62-year-old Nigerian man in apparent good health who was found to have a markedly elevated serum total alkaline phosphatase (ALP) of 1179 U/l (reference range, 40–115 U/l) 4 years ago during a routine medical check-up in the USA. He had no history suggestive of PDB and also had no known family history of bone disease. Examination findings were not remarkable except for a relatively large head. A repeat ALP in our centre was 902 U/l (reference range, 40–120 U/l). Cranial CT scan showed diffuse cranial vault thickening consistent with Paget's disease which was confirmed by Tc-99m hydroxymethylene diphosphonate. He was placed on 40 mg alendronate tablets daily for 6 months. The patient has remained asymptomatic and has been in continuing biochemical remission during the 3-year follow-up period. The most recent ALP result is 88 U/l (reference range, 30–132 U/l) in April 2015. LEARNING POINTS: Serum total alkaline phosphatase remains a sensitive marker of bone turnover and an isolated increase above the upper limit of normal warrants more intense scrutiny in form of investigations targeted at excluding PD. Paget's disease is very rare but can occur in the Africans as seen in this Nigerian man and most patients are asymptomatic. Asymptomatic patients can benefit from treatment if disease is active, polyostotic or the lesions are located in bones with future risk of complications such as long bones, vertebrae and skull. Bisphosphonates are still the mainstay of treatment and alendronate is a useful therapeutic option for treatment.