a 52-year old man visited our hospital complaining of pain in the right hip and gait disturbance beginning one month prior without any traumatic injury . the patient , a policeman , spent about 45 minutes a day for a year commuting to work until the pain started . he was able to do level - ground walking until admission , but had progressive discomfort while ascending stairs and his gait disturbance developed to the degree of being limited to walking no higher than a single story . physical examination revealed no limitations to range of motion and the patient was negative for patrick 's test and signs of impingement . no local heating sense or erythema around involved side was observed , and systemic symptoms indicating infectious condition were not present . there was no specific finding in plain radiography of the hip joints , but increased uptake of the radioactive isotope was detected in the right femoral head in technetium-99 m nuclear medicine imaging . non - enhanced mri of the hip joints revealed low signal intensity on t-1 weighted images and high signal intensity on t-2 weighted images in the right femoral head , neck , marrow of the proximal metaphysis , and surrounding soft - tissue edema . in addition , about 1.5 cm - long fluid collection was observed in the iliopsoas muscle ( fig . blood cell counts , liver and renal functional tests and a serum electrolyte test revealed normal results , a white blood cell count of 8,600/l ( normal range , 4,000 - 10,000/l ) , 63% segmented neutrophils ( normal range , 40 - 80% ) , an erythrocyte sedimentation rate of 5 mm / hr ( normal range , 0 - 15 mm / hr ) , and a c - reactive protein of 0.02 mg / dl ( normal range , 0 - 0.5 mg / dl ) , excluding a uric acid of 8.1 mg / dl ( normal range , 4.0 - 7.0 mg / dl ) . since there was no evidence of bone tumor or malignancy , the patient was diagnosed with bmes . t - score was 2.3 ( bone mineral density [ bmd ] 0.770 g / cm ) in the l4 according to lumbar spine bmd using dual energy x - ray absorptiometry ( dexa ) . we planned to perform femoral head core decompression if symptoms worsen and followed up with the patient every other week concurrent with oral administration of nsaids ( aceclofenac 100 mg , twice a day ; 8 weeks ) and limited physical activity . although the hip pain and gait disturbance were improved from the 6th week after onset of symptoms , no changes were observed between mri scans taken initially and 2 months after presenting symptoms . follow - up mri presented significantly decreased signal intensity in bone marrow and soft tissues compared to the previous mri scan and fluid collection within the iliopsoas muscle decreased ( fig . the patient returned to daily activities 5 months after onset of disease without pain and no physical limitation was present . for the following 3 years , the patient made no visits to our hospital . after 3 years , however , the patient was re - admitted with newly developed left hip pain that had persisted for the previous 3 weeks without a history of trauma . the patient reported experiencing no discomfort for 3 years after remittance and no change in occupation or daily activities . no definitive abnormal findings were shown in plain radiography of the hip joints , and mri showed low signal intensity on t1-weighted images in the left femoral head , neck , and greater and lesser trochanteric area , and high signal intensity ( representing bone marrow edema on t2-weighted images . previously observed fluid collection in the right side was not found in the iliopsoas muscle ( fig . 3 ) . excluding fluid collection in the iliopsoas muscle , when compared to previous mri findings on the right side , the involved lesion area and signal intensity had similar patterns . using the dexa test , the t - score was 2.3 ( bmd 0.760 g / cm ) in the l4 and 1.2 ( bmd 0.776 g / cm ) in the left femoral neck . the patient was administered , administered nsaids ( aceclofenac 100 mg , twice a day ; 4 weeks ) and advised to avoid excessive physical activity again . his pain and gait disturbance began to improve and completely resolved 2 months after onset of symptoms . the patient was satisfied with treatment and returned to normal daily activities , and no abnormal findings were found six months after symptoms started . bone marrow edema syndrome ( bmes ) is a rare disease of unknown etiology that needs to be differentiated from other conditions among patients complaining of hip pain . according to resnick and niwayama5 ) , bmes is assumed to be associated with neurovascular problems , reflex sympathetic dystrophy , ischemic necrosis and others . although there is a controversy about progression from bmes to avascular necrosis of the femoral head among researchers , the presence of osteonecrosis when bone marrow edema is observed is known as an important factor for treatment and a predictor of disease progression . according to solomon2 ) , bone marrow edema without osteonecrosis is characterized by hypervascularity and spontaneous regression ; however , the condition associated with osteonecrosis may progress to ischemic injury with femoral head collapse and joint destruction2 ) . moreover , mri is used as a modality in confirming initial diagnosis and for follow - up as it may provide definite findings3 ) . the patient in this case report was diagnosed with bmes based on the presence of bone marrow edema without osteonecrosis . since bmes is a self - limiting condition , conservative therapy includes non - weight bearing , immobilisation of the affected area , and pain management using medications such as nsaids and opiates7 ) . in addition to analgesics , steroids , bisphosphonates and calcium channel blockers can be administered7 ) , high energy extracorporeal shock wave therapy can be used when treating severe or chronic pain6 ) , or core decompression can be performed to prevent progression to osteonecrosis if pain and dysfunction persist despite conservative therapy7 ) . despite spontaneous regression over time , the effects of conservative treatment including medications and long - term prognosis have been insufficiently investigated . although we followed a conservative treatment plan with the patient , considering surgical management only as an alternative option , symptoms improved within a relatively short period of time ( 3 months after onset of symptoms on the right side and 2 months after onset on the left side ) . niimi et al.8 ) reported a case with low bmd in the femoral neck at the time of diagnosis and spontaneous recovery . in our case report , we were unable to measure changes in bmd at the time of symptom onset and recovery because dexa was performed on the spine only at the initial onset of symptoms . low t - score on the lumbar spine ( 2.3 at l4 at the first and the second admission ) implies that previous poor bone quality may be associated with the occurrence of bmes , however , the relatively high t - score on the hip area is diminishing the relation between bone quality and the occurrence of bmes . previous studies reported cases of unilateral or simultaneous bilateral bmes . in this case report , under nearly same social and physical conditions , bmes was diagnosed at different times on each side of the hip and a similar case has not been previously reported in the domestic literature . furthermore , although bmes is a rare condition , differential diagnosis with other diseases associated with bone marrow edema is crucial , and the possibility of bmes on the opposite side of the hip at different onset times should not be ruled out .
bone marrow edema syndrome ( bmes ) is a rare condition which mainly affects the hip area . 
 the etiology and pathogenesis of bmes is still unclear . 
 pain near the affected area , regional osteoporosis , bone marrow edema ( identified using magnetic resonance imaging ) and spontaneous regression within 6 - 12 months are the main characteristics of bmes . in this case , a 52-year - old male was diagnosed with bmes of the right hip followed by spontaneous subsiding of symptoms . after 3 years , and under nearly the same social and physical conditions , he was admitted again with newly developed left hip pain and again diagnosed with bmes . 
 we report this rare case since a similar one has not been previously reported in the domestic literature and may be considered valuable for basic research relating to the pathogenesis of bmes .