Neurosarcoid

KEY FACTS

Terminology

• Multisystem inflammatory disease characterized by noncaseating epithelioid-cell granulomas

Imaging

• Solitary or multifocal CNS mass(es) ± abnormal CXR

  • CXR abnormal in > 90% with neurosarcoid (NS)

• Wide spectrum of MR manifestations

  • Dura-arachnoid thickening (diffuse or focal))

  • May coat pia, cranial nerves, fill internal auditory canals

  • Pituitary stalk/hypothalamus thickening

  • Can thicken, infiltrate choroid plexi

  • Can infiltrate orbital adnexa, optic nerve

  • Rare

    • –

      Small vessel vasculitis/angiitis in white matter

    • –

      Focal parenchymal mass

Top Differential Diagnoses

• Meningitis

• Meningioma

• Metastases

• Lymphocytic hypophysitis

Pathology

• Etiology remains unknown

• May infiltrate along perivascular spaces into brain

Clinical Issues

• Often indolent disease (up to 50% asymptomatic)

• CNS involved in 5% (clinical) to 27% (autopsy)

  • Most common CNS symptom: Cranial nerve deficit(s), most often facial nerve palsy

• Natural history

  • 2/3 of NS self-limited monophasic illness; remainder have chronic remitting-relapsing course

Diagnostic Checklist

• Protean manifestations make NS “great mimicker”

TERMINOLOGY

IMAGING