Dural Sinus Lesion, General

Bronwyn E. Hamilton, MD

Anne G. Osborn, MD, FACR

DIFFERENTIAL DIAGNOSIS

Common

Arachnoid Granulations, Dural Sinuses
Dural Sinus Hypoplasia-Aplasia
Thrombosis, Dural Sinus
Dural A-V Fistula

Less Common

Meningioma
Metastasis
Lymphoma
Depressed Skull Fracture
Intracranial Hypotension

Rare but Important

Dural Venous Sinus Stenosis
Thrombophlebitis
Polycythemia
Hemangioma
Leukemia
Rosai-Dorfman Disease
Extramedullary Hematopoiesis
Lipoma
Masson Vegetant Intravascular Hemangioendothelioma

ESSENTIAL INFORMATION

Key Differential Diagnosis Issues

Includes generic lesions affecting ALL dural venous sinuses
- Cavernous sinus (CS) unique because of contents, proximity to skull base
- Has diagnoses (e.g., perineural metastasis, aneurysm, schwannoma) that do not affect other sinuses
Imaging challenge: Differentiate dural sinus thrombosis (DST) from stenosis, anatomic variants
- CTV best
- MRV shows anatomical narrowing/occlusion
- T2* (GRE/SWI) shows thrombus

Helpful Clues for Common Diagnoses

Arachnoid Granulations, Dural Sinuses
- Can be large (> 1 cm), remodel calvarium
  - May narrow but not occlude sinus
- Round/ovoid, well-circumscribed
- CSF density/signal intensity
Dural Sinus Hypoplasia-Aplasia
- Seen in up to 1/3 of normal scans
  - Transverse sinus (TS) most common site
- “Flow gaps” on MRV can mimic DST
  - Confirm “flow gaps” on source data
  - No “blooming” thrombus on T2*
  - If MRV is unclear, CTV helpful
Thrombosis, Dural Sinus
- Symptoms vary with extent of thrombus, collaterals, cortical vein involvement
- NECT
  - Hyperdense clot in sinus
  - Cortical/subcortical hemorrhages (bilateral parasagittal if superior sagittal sinus or temporal lobe if vein of Labbe)
  - ± Edema (vasogenic > cytotoxic)
- CECT shows “empty delta sign”
- MR
  - Loss of normal “flow void”
  - Clot elongated, fills sinus, shows susceptibility on T2*
  - Confirm with MRV
- Chronic thrombosis difficult diagnosis
  - Progressive recanalization &/or granulation tissue forms
  - Chronic thrombus enhances, mimicking patent dural sinus
  - Dura also thickens, enhances; bizarre-appearing collaterals may mimic vascular malformation
  - May have clinical, imaging findings of intracranial hypertension (pseudotumor cerebri)
Dural A-V Fistula
- Most acquired; clinical manifestations vary
  - Pulsatile tinnitus, exophthalmos
  - Less common = progressive encephalopathy (dementia), diffuse white matter hyperintensity from chronic venous hypertension
- Imaging
  - Flow voids within wall of thrombosed dural sinus common
  - High grade lesions prone to intracranial (usually parenchymal) hemorrhage
  - Small web of vessels on collapsed MRA images may suggest diagnosis
  - DSA gold standard for diagnosis

Helpful Clues for Less Common Diagnoses

Meningioma
- Enhancing dural-based mass ± “tail”
- May invade, occlude, or compress dural sinuses
- Bony hyperostosis variable
Metastasis
- Systemic primaries may compress or invade dural sinuses
- Usually arise from calvarium with secondary dural involvement
Lymphoma
- Dural-based mass(es) common in metastatic lymphoma
Depressed Skull Fracture
- May lacerate/compress/occlude dural sinus
- ± Venous epidural hematoma (EDH)
- Venous EDH develops slowly, presents late!
Intracranial Hypotension
- Dural venous engorgement, enhancement
- Slumping midbrain, tonsillar descent, SDHs

Helpful Clues for Rare Diagnoses

Dural Venous Sinus Stenosis
- Focal short segmental narrowing on CTV, MRV, or DSA (venous phase)
- May cause intractable headaches (intracranial hypertension)
- Patients with suspected symptomatic venous outflow restriction, pressure gradient at venography may improve after stent
Thrombophlebitis
- Complication of infection (meningitis, rhinosinusitis, or mastoiditis)
- Infection spreads easily due to valveless nature of intracranial venous system
- May cause septic venous thrombosis
Polycythemia
- High hematocrit → “dense” dural sinus
Hemangioma
- Capillary/cavernous vasoformative neoplasm
- Convexity dura or venous sinus (CS most common)
- May present with mass effect or intracranial hypertension
Leukemia
- Dural-based enhancing masses
- May compress/invade dural sinuses
Rosai-Dorfman Disease
- Younger patients
- Lymphadenopathy > paranasal sinus disease
- Lymphadenopathy usually coexists if CNS disease is present
- Solitary/multiple dural-based enhancing masses
Extramedullary Hematopoiesis
- Dural-based enhancing masses
- Dural sinus compression/invasion rare
Lipoma
- Fat in dural sinus rare; CS most common
Masson Vegetant Intravascular Hemangioendothelioma
- Rare benign tumor of young patients
- Papillary endothelial hyperplasia
- Can cause stenosis, hypertension
- Can mimic meningioma