IgG4-related hypertrophic pachymeningitis

Polycystic
subdural hygroma associated with immunoglobulin G4-related intracranial hypertrophic pachymeningitis: a case report. Brain MRI (gadolinium enhanced T1-wighted images) on admission. MRI revealed polycystic subdural hygroma, hematoma, and diffuse thickening of the dura mater when probed using contrast enhancement (MRI, magnetic resonance imaging)
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Dural masses:
meningiomas and their mimics. IgG4-related hypertrophic pachymeningitis with skull invasion. a Post-contrast coronal T1-weighted MR image showing linear dural thickening and enhancement overlying the left cerebral convexity. Note that the overlying calvarial bone marrow signal is abnormal. b Apparent diffusion coefficient (ADC) map showing restricted diffusion in the lesion overlying the left parietal region. c Post-contrast axial T1-weighted image of the same lesion with enhancing soft tissue seen invading the skull. d Axial fluid attenuated inversion recovery (FLAIR) image showing the lesion is predominantly hypointense due to fibrosis with foci of hyperintensity
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IgG4-related
intracranial hypertrophic pachymeningitis with skull hyperostosis: a case report. Preoperative images. A. Anteroposterior view of skull X-ray radiography shows left skull bone effacement near the vertex. B-D. Magnetic resonance image shows an area of abnormal bony marrow over left high convexity showing loss of normal fatty marrow with moderate enhancement after contrast injection (arrow). Mild subperiosteal soft tissue thickening and adjacent dura and leptomeningeal thickening and enhancement (arrowhead) are apparent. The left central and precentral sulci are filled with abnormal enhancing lesion (white arrows).
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IgG4-related hypertrophic pachymeningitis is one of the many manifestations of IgG4-related disease which represents a fibroinflammatory condition that can affect any organ. IgG4-related pachymeningitis is increasingly being recognized as the etiology of hypertrophic pachymeningitis, an entity which until recently was thought to be idiopathic.

Epidemiology

It typically older men with a mean age of presentation of 59 years.

Head and neck manifestations of IgG4 disease are more common than hypertrophic pachymeningitis. Salivary gland involvement is the most common head and neck manifestation.

Clinical presentation

Patients may be asymptomatic, but if symptomatic, they commonly present with headaches. Symptoms may be related to mechanical compression of vascular or neural structures. Patients often present with systemic manifestations of the disease.

Pathology

Meningeal biopsy reveals "storiform" fibrosis with lymphoplasmacytic infiltration of IgG4-positive plasma cells (either > 10 cells/HPF or IgG4:IgG ratio >40%) and obliterative phlebitis.

Markers

Elevated serum IgG4 level and CSF IgG4 oligoclonal bands.

Radiographic features

In addition to radiographic features of IgG4-related hypertophic pachymeningitis, which are detailed below, other associated head and neck manifestations of IgG4-related disease, such as IgG4-related-hypophysitis, lacrimal and salivary gland enlargement and inflammation, orbital pseudotumor, and perineural spread along trigeminal and other cranial nerves, may also be seen.

CT

Findings on CT can be very subtle. Plaque-like dural thickening may or may not be evident. Focal nodular thickening may mimic a meningioma.

MRI

The following signal characteristics are seen:

  • T1: isointense dural thickening 
  • T1 C+ (Gd): homogeneous enhancement
  • T2/FLAIR: markedly hypointense due to underlying fibrosis (a reasonably specific imaging finding)
  • GRE/SWI: hypointense due to underlying fibrosis
FDG-PET

FDG-PET has limited utility for detecting pachymeningitis due to avid brain uptake of FDG and inferior spatial resolution of PET compared to MRI. FDG-PET can detect systemic/multiorgan manifestations of IgG4-related disease and can be utilized to assess for treatment response.

Treatment and prognosis

IgG4-related hypertrophic pachymeningitis is responsive to high dose steroids. Additionally, immunomodulators have shown variable efficacy.

Generally there is a favorable prognosis.

Differential diagnosis

Siehe auch:
Assoziationen und Differentialdiagnosen zu IgG4-assoziierte hypertrophe Pachymeningitis:
hypertrophe
Pachymeningitis
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IgG4-assoziierte
Erkrankung
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