title: A case of IgG4-related hepatic inflammatory pseudotumor replaced by an abscess after steroid treatment.
abstract: BACKGROUND
  Hepatic inflammatory pseudotumor (IPT) is a rare disease which often mimics a malignant tumor and is therefore often misdiagnosed and surgically resected. Recently, a concept of IgG4-related diseases (IgG4-RD) has been proposed that is becoming widely recognized and includes IgG4-related hepatic IPT. Corticosteroids are widely accepted as the standard treatment.
  
  
  METHODS
  A 72-year-old Japanese man, who had been followed for ten years after surgery and chemotherapy for treatment of hilar and lower bile duct cancers, developed intermittent fever and abdominal pain and visited this hospital. Blood examinations revealed an inflammatory reaction, worsened glucose intolerance, and an increased level of serum IgG4 (137 mg/dL). Computed tomography (CT) revealed a 5 cm-sized mass in hepatic segment 7. Because of his cancer history, not only was a benign mass suspected, but there was also the possibility of a recurrent biliary malignancy. Liver biopsy was performed and the histology met the criteria for IgG4-related IPT. Corticosteroid therapy was initiated and his symptoms quickly resolved. However, two months later, a repeat CT demonstrated that the hepatic mass had been replaced by an abscess. The abscess was initially refractory, despite tapering corticosteroid treatment, controlling diabetes by intensive insulin therapy, administration of antibiotics, and percutaneous abscess drainage. Finally, after six months, the condition resolved.
  
  
  CONCLUSIONS
  The diagnosis of hepatic IPT is sometimes difficult. To differentiate it from a malignant tumor, histological examination is necessary. Although corticosteroids are recognized as the standard therapy, unexpected and critical complications can develop in cases of IgG4-related hepatic IPT.
authors.affiliation: Division of Endoscopy, Shizuoka Cancer Center, 1007 Shimonagakubo, Nagaizumi, Suntogun, Shizuoka, 411-8777, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Shibata
authors.affiliation: Division of Endoscopy, Shizuoka Cancer Center, 1007 Shimonagakubo, Nagaizumi, Suntogun, Shizuoka, 411-8777, Japan. h.matsubayashi@scchr.jp.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Matsubayashi
authors.affiliation: Division of Interventional Radiology, Shizuoka Cancer Center, Nagaizumi, Suntogun, Shizuoka, 411-8777, Japan.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Aramaki
authors.affiliation: Division of Hepato-Biliary-Pancreatic Surgery, Shizuoka Cancer Center, Nagaizumi, Suntogun, Shizuoka, 411-8777, Japan.
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Uesaka
authors.affiliation: Division of Infectious Diseases, Shizuoka Cancer Center, Nagaizumi, Suntogun, Shizuoka, 411-8777, Japan.
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Tsutsumi
authors.affiliation: Division of Pathology, Shizuoka Cancer Center, Nagaizumi, Suntogun, Shizuoka, 411-8777, Japan.
authors.forename: Keiko
authors.initials: K
authors.lastname: Sasaki
authors.affiliation: Division of Endoscopy, Shizuoka Cancer Center, 1007 Shimonagakubo, Nagaizumi, Suntogun, Shizuoka, 411-8777, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Ono
mesh_terms: D000038:Abscess / Q000139:chemically induced* / Q000628:therapy; D000305:Adrenal Cortex Hormones / Q000009:adverse effects* / Q000627:therapeutic use; D000368:Aged; D003937:Diagnosis, Differential; D006104:Granuloma, Plasma Cell / Q000175:diagnosis* / Q000188:drug therapy* / Q000276:immunology; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood*; D008107:Liver Diseases / Q000175:diagnosis* / Q000188:drug therapy* / Q000276:immunology; D008297:Male
chemical_list: D000305:Adrenal Cortex Hormones; D007074:Immunoglobulin G
keywords: Abscess; Hepatic inflammatory pseudotumor; IgG4-related disease; Liver biopsy; Steroid