autoimmune hepatitis ( aih ) is a chronic progressive hepatitis characterized by positive antinuclear antibody ( ana ) and hypergammaglobulinemia , portal inflammatory cell infiltration with plasmacyte dominance , and piecemeal necrosis 1 . acuteonset cases of aih account for up to 25% of all cases , some of which present as fulminant liver failure 2 . the diagnosis of aih is established by the criteria defined by the international autoimmune hepatitis group and by the exclusion of other causes 3 . however , acuteonset aih is not typical , and this diagnosis is difficult 4 , 5 , 6 . there are few reports of complications after recovery from fulminant liver failure secondary to aih . on the other hand , risk factors of actinomycosis are poor oral hygiene resulting in tooth decay , chronic lung disease , alcoholism , and other disorders resulting in reduced immunocompetence 7 . the present report describes an interesting case of an osteolytic lesion ( actinomycosis ) after recovery from fulminant liver failure induced by aih . the patient was a 77yearold woman whose chief complaints were jaundice , general fatigue , and brown urine . the patient was seeing a local doctor for chronic gastritis and was given lansoprazole 15 mg once a day , mosapride citrate hydrate 5 mg three times a day , etizolam 0.5 mg once a day , and an unknown herbal medicine , without signs of hepatic injury . on 15 may 2009 , she had general fatigue , but no laboratory dysfunction was shown . on 23 june 23 2009 , she had jaundice and brown urine , and laboratory data showed liver dysfunction . while she had eaten raw foods within the previous month , she had not eaten raw oysters . on admission , her consciousness was clear , and although yellowing of the bulbar conjunctiva was noted , no other abnormalities were identified . laboratory findings on admission ( table 1 ) included aspartate aminotransferase ( ast ) , 1735 iu / l ; alanine aminotransferase ( alt ) , 1707 iu / l ; total bilirubin ( tb ) , 7.13 mg / dl ; prothrombin time rate ( pt% , international normalized ratio [ inr ] ) , 45% , 1.5 ; hepatitis b surface antigen ( hbsag ) negative ; hepatitis c virus ( hcv ) rna negative ; antiliver / kidney microsome type 1 antibody(lkm1 ) negative , and other virus antibodies negative . furthermore , as levels of ana ( 320 ) and immunoglobulin g ( igg ) ( 1793 mg / dl ) were elevated , aih was suspected . although ast and alt levels began to improve after the injection of glycyrrhizin , tb and pt% deteriorated to 17 mg / dl and 35% , respectively . while we wanted to perform liver biopsy for the diagnosis of aih , it was deemed too dangerous due to severe liver failure , especially with regard to the abnormal pt% . however , the patient developed fulminant liver failure with stage 2 hepatic encephalopathy on the eighth clinical day , and plasma exchange was performed for 3 days . levels of ast , alt , tb , and the symptomatology of hepatic encephalopathy improved , but freshfrozen plasma ( ffp ) was transfused every day from 12th clinical day due to a lack of response in pt% . on the 19th clinical day , general fatigue and stage 2 hepatic encephalopathy developed , and plasma exchange was again performed for 3 days from the 24th clinical day . the ast and alt levels subsequently normalized , and the prednisolone dose was decreased to 20 mg / day on the 28th clinical day . the dose was decreased to 15 mg / day 1 week later , as ast and alt remained normal . on the 60th clinical day , she was discharged , and the prednisolone dose was decreased to 7.5 mg / day . at the outpatient examination on the 78th clinical day , abdominal ultrasound and helical dynamic ct scan were performed , showing a 4cm osteolytic tumor of the 10th right rib ( fig . the suspicion of metastasis was raised , but gastrointestinal endoscopy and colon endoscopy did not reveal evidence of any malignant tumor . ( b , c ) ultrasound finding of tumor in the 10th right rib is heterogeneous . ( d ) doppler ultrasound finding of tumor in the 10th right rib is hypovascular . ( e  h ) abdominal unenhanced and enhanced computed tomography ( ct ) scan findings at 78 days after first admission . ( e ) plane , ( f ) arterial phase , ( g ) equilibrium phase , and ( h ) venous phase . an increase in serum cancer antigen 125 ( ca125 ) level was noted , but gynecologic evaluation failed to detect any malignant tumor . on the 125th clinical day , the patient presented with severe pain of the right hip joint and was readmitted with suspicion of the osteonecrosis of the femoral head . however , she was subsequently diagnosed with suppurative inflammation of the hip joint due to methicillinsensitive staphylococcus aureus ( mssa ) and was treated by an orthopedist . her hip joint pain improved by the 146th clinical day , and a biopsy of the liver and the 10th right rib tumor was performed . examination of the liver specimen showed that the portal tract was infiltrated with inflammatory cells ( including plasma cells ) , the parenchymal architecture had been partially disrupted , and surviving hepatocytes had formed glandlike rosettes . examination of the 10th right rib specimen showed infiltration of lymphocytes and plasma cells , fibrosis , and the druse ( arrow ) with abscess formation ( fig . liver biopsy finding : the portal tract is infiltrated with inflammatory cells , including plasma cells . the parenchymal architecture is partially disrupted . surviving hepatocytes form glandlike rosettes ( arrow ) . right rib tumor biopsy finding : infiltration of lymphocytes and plasma cells and fibrosis are seen . druse ( arrow ) with abscess formation is seen . in conclusion , during recovery from fulminant liver failure induced by acute onset aih , the patient was diagnosed with actinomycosis of the 10th right rib . this patient had been treated with amoxicillin . however , due to the development of amoxicillin allergy , the treatment was discontinued immediately , and treatment with levofloxacin hydrate was initiated . on admission , the present patient was suspected of having acuteonset aih , because ana was 320 , eight times the normal value , and igg was 1793 mg / dl , 1.1 times the normal value . however , since she had a history of taking various medicines , the possibility of druginduced hepatic injury could not be excluded . as the patient scored < 2 points on the diagnostic criteria scale for acute druginduced hepatic injury established by digestive disease week  japan ( ddwj ) 8 , we believed that druginduced hepatic injury seemed unlikely . according to her clinical course and the international diagnostic criteria for aih 1 , she was finally diagnosed with recovery from fulminant liver failure induced by acuteonset aih , likely type 1 aih . a nationwide survey of patients with fulminant hepatitis and lateonset hepatic failure in japan revealed that outcomes were especially poor in aih patients ( the survival rate was 17.1% without liver transplantation ) 9 . as this patient was older than 75 years and repeatedly developed stage 2 hepatic encephalopathy , we believed that she had poor prognosis . although this patient might have benefitted from corticosteroids and plasma exchange at the early stage of fulminant aih , there is a little evidence for the efficacy of these treatments 6 , 10 . although this patient recovered from fulminant liver failure due to aih , she developed suppurative inflammation of the hip joint due to mssa and developed a right rib tumor due to actinomyces . actinomycosis occurs in the cervicofacial ( 6070% ) , abdominal ( 2040% ) , and thoracic ( 920% ) areas . risk factors of actinomycosis are poor oral hygiene resulting in tooth decay , chronic lung disease , alcoholism , and other disorders resulting in reduced immunocompetence 7 . in the present case , immunosuppression due to corticosteroids might have contributed to the development of the right rib actinomycosis . however , the frequency of actinomycosis development secondary to the use of corticosteroid is unclear . actinomyces are part of the normal oral flora and colonize the human digestive tract 7 , 13 , 14 . although the aspiration of saliva containing actinomyces is considered to be responsible for cases of pulmonary actinomycosis , the right rib actinomycosis in this patient might have occurred via hematogenous spread , as there was no invasion from the right lung . this immunocompromised patient might have also developed hip infection due to hematogenous spread of mssa . the diagnosis of thoracic actinomycosis is difficult , and the differential diagnosis includes pulmonary malignancy 7 , 13 , 14 . thus , the diagnosis of actinomycosis depends on growth of the bacteria in culture and the discovery of sulfur granules in the pathologic specimen . in this patient , when treating patients with fulminant liver failure due to aih , the possibility of such rare occurrences should be kept in mind . in conclusion , this report described an interesting case of an osteolytic lesion secondary to actinomycosis after fulminant liver failure induced by aih .
key clinical messagethis report highlights an interesting case of an osteolytic lesion ( actinomycosis ) after fulminant liver failure induced by autoimmune hepatitis ( aih ) . when treating patients with fulminant liver failure due to aih using immunosuppressive drugs , such as steroids , the possibility of such rare occurrences should be kept in mind .