paget 's disease ( pd ) of bone is a focal , progressive disorder of accelerated bone remodeling and can lead to bone pain and several complications , including deformities , fractures , and secondary osteoarthritis . although the pathophysiology of pd is very complicated and not well known , the primary lesion is the abnormally increased and activated osteoclast in pd . bisphosphonates , which is the most potent anti - resorptive drug , have been the most effective agents available for the treatment of pd . among the bisphosphonates for osteoporosis treatment , zoledronate is a nitrogen - bound intravenous bisphosphonate with highest potency and longest administration interval . we reported a patient with pd , who had inadequate responses to therapy with pamidronate , has had a clinical remission with intravenous zoledronate . in may , 2010 , a 49-year - old woman presented with 4 year history of both buttock pain . iu / l ( reference range , 30 to 115 iu / l ) . a bone scan , which undergone at outside hospital 4 year ago , confirmed pagetic changes in the left ilium ( fig . 1 ) . and , pelvis anterior - posterior radiograph obtained at our hospital revealed a typical mosaic pattern of pd in her pubic and left ilium ( fig . her weight was 61.4 kg , height was 162 cm , and body mass index was 23.4 kg / m . range of motion at left hip was decreased due to pain , and she walked with a mild limp . although the level of alp was within reference range , pamidronate treatment was started orally for 3 months , because she had a severe pain . however , her pain intensity level increased . iu / l , and bone scan show still hot uptake in her both ilium and lumbar vertebrae ( fig . subsequently , she received intravenous zoledronate ( 5 mg ) in a single dose at august , 2010 . after this treatment , we evaluated clinical and biochemical remission and improvement in bone scan . three months after administration zoledronate , alp decreased 26 iu / l , and a severe pain and limping gait disappeared . six months after intravenous zoledronate , alp decreased 21 u / l , and bone scan showed the improvement , which means a response of zoledronate ( fig . iu / l , and bone scan showed hot uptake in both ilium and lumbar vertebrae ( fig . we report a patient with pd of bone , resistant to pamidronate treatment in whom intravenous zoledronate produced clinical remission and an improvement in the bone scan during 3 years . in united states population over 55 years , the incidence of pd is estimated to approximately 2 - 5% . however , the incidence is very low , and had not been well - known in korea . serum alp is an indicator of osteoblast activity and the primary marker for assessment of pd . however , this patient had low alp at initial presentation , which can not allow physician to suspect pd by a screening laboratory profile . bone scan can be used as a complementary method to diagnose and monitor the activity of pd . recent treatment guidelines recommend an use of bisphosphonate for pd to prevent disease progression and associated - complications , even in asymptomatic patients , especially with critical anatomic location such as skull , spine , weight - bearing bones , or the acetabular regions . oral bisphosphonate has been traditionally used for this , but compliance of oral bisphosphonate is too low , because of complex ingesting methods and gastro - esophageal irritation . therefore , annually intravenous zoledronate could be alternative optional . a clinical trial reported that a single 5 mg zoledronic acid infusion normalized alp levels in 89% of patients , compared with 58% in the control group administered oral risedronate , 30 mg / day for 60 for 2 months . although advantages of zoledronate include the convenience of a 15 minute infusion , approximately 40% of patients experienced zoledronate - associated symptoms ( flu - like illness , pyrexia , myalgia , arthralgia , bone pain ) , typically within the first 3 days after the infusion , with most symptoms resolving within 3 days after onset . this case study demonstrated that a patient with pd who had been treated unsuccessfully with oral bisphosphonates was effectively treated with a 5 mg infusion of zoledronate . the ability of zoledronate to provide a sustained remission offers many advantages for patients with pd and may lead to considerable benefits for the long term in preventing or minimizing complications .
paget 's disease ( pd ) of bone is characterized by increase of bone resorption by atypical osteoclasts , followed by rapid new bone formation resulting in a disorganized mosaic bone . 
 although the pathophysiology is not fully understood , bisphosphonate , which is a potent anti - resorptive agent for treatment of osteoporosis , have been the most effective agents available for the treatment of pd . 
 we report a case of pd of bone in a 49-year - old woman patient , who was treated with intravenous zoledronate .