title: IgG4-Related Hypertrophic Pachymeningitis at the Falx Cerebrii with Brain Parenchymal Invasion: A Case Report.
abstract: BACKGROUND
  Hypertrophic pachymeningitis has been described as a manifestation of a number of conditions, like infection and neoplasms such as dural carcinomatosis or lymphomas. IgG4-related hypertrophic pachymeningitis is a new entity identified during the past decade and most reports described pachymeningeal involvement only.
  
  
  METHODS
  We present a 58-year-old woman with isolated IgG4 hypertrophic pachymeningitis at the falx cerebrii that exhibited cerebral parenchymal invasion. She initially presented with left lower limb weakness. Magnetic resonance imaging of brain showed a contrast enhancing lesion located at the falx and that eroded into the right frontal lobe. Subsequent excisional biopsy confirmed the lesion with brain parenchyma invasion. The pathologic diagnosis was IgG4-related disease. She had no evidence of extracranial involvement.
  
  
  CONCLUSIONS
  Overall, this is an uncommon condition that may exhibit parenchymal invasion. Surgical biopsy would serve to establish a definitive diagnosis, and prompt comprehensive management of what is essentially a systemic and treatable condition.
authors.affiliation: Division of Neurosurgery, Department of Surgery, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong.
authors.forename: Lai-fung
authors.initials: LF
authors.lastname: Li
authors.affiliation: Division of Neurosurgery, Department of Surgery, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong.
authors.forename: Philip Yat-hang
authors.initials: PY
authors.lastname: Tse
authors.affiliation: Division of Neurosurgery, Department of Surgery, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong.
authors.forename: Frederick Chun-pong
authors.initials: FC
authors.lastname: Tsang
authors.affiliation: Department of Pathology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong.
authors.forename: Regina Cheuk-lam
authors.initials: RC
authors.lastname: Lo
authors.affiliation: Division of Neurosurgery, Department of Surgery, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong.
authors.forename: Wai-man
authors.initials: WM
authors.lastname: Lui
authors.affiliation: Division of Neurosurgery, Department of Surgery, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong. Electronic address: gilberto@hkucc.hku.hk.
authors.forename: Gilberto Ka-kit
authors.initials: GK
authors.lastname: Leung
mesh_terms: D001327:Autoimmune Diseases / Q000175:diagnosis* / Q000276:immunology* / Q000473:pathology; D001706:Biopsy; D005260:Female; D005625:Frontal Lobe / Q000276:immunology* / Q000473:pathology*; D006801:Humans; D006984:Hypertrophy; D007074:Immunoglobulin G / Q000097:blood*; D008581:Meningitis / Q000175:diagnosis* / Q000276:immunology* / Q000473:pathology; D008875:Middle Aged; D013116:Spinal Cord / Q000276:immunology* / Q000473:pathology*
chemical_list: D007074:Immunoglobulin G
keywords: Autoimmune; IgG4; Pachymeningitis