This document discusses extra-axial masses, specifically meningiomas. It provides details on the typical presentation, demographics, pathology, imaging features and diagnosis of meningiomas. On imaging, meningiomas usually appear as well-circumscribed, dural-based masses that enhance strongly with CT and MRI. They typically show calcification on CT and homogenous enhancement post-contrast. The document emphasizes that meningiomas are the most common extra-axial brain tumors and often appear as convexity or parasagittal masses, with females being more commonly affected.

1. EXTRA-AXIAL MASSES
( TYPICAL MENINGIOMA )
BY:
DR. HASSAN ALQARNI
R1 RADIOLOGY RESIDENT
SAUDI BOARD

5. Top Differential Diagnoses
• Meningioma
• Dural metastasis
• Granuloma (TB, sarcoid)
• Idiopathic hypertrophic pachymeningitis
• Extramedullary hematopoiesis
• Hemangioma, dura/venous sinuses

6. •
Meningioma
Hyperostosis, cortical
irregularity, calcification
Metastases, Meningeal
Multiple > solitary lesions
Often known extracranial primary neoplasm

7. Tuberculosis
• Abnormal CXR, lab values
• Travel history to endemic areas,
immunocompromised
Hypertrophic Pachymeningitis
• localised inflammatory thickening of
the dura

8. Extramedullary Hematopoiesis
Patients with chronic anemia or marrow depletion
Multiple > solitary

9. Diagnosis :
Meningioma

10. Meningioma
• Most common extra-axial neoplasm of adults and accounts for
15% of all intracranial neoplasms, second only to gliomas in overall
prevalence.
• The peak age of presentation is 50 to 60 years. For both intracranial
(2:1) and intraspinal (4:1) meningiomas,
• Females are more commonly affected.
• Because the tumor is hormonally sensitive, it may increase in size
during pregnancy.
• Multiple tumors (up to 9% of all cases) are associated with
neurofibromatosis.

11. Pathology
• Arises from arachnoid cap cells with some probable
contribution from dural fi broblasts and pial cells.
• It is believed that intraventricular meningiomas arise
from arachnoidal cap cell rests buried within the
choroid plexus.

12. Clinical Presentation
• Most common signs/symptoms
– < 10% of all meningiomas are symptomatic
– Symptoms depend on tumor site
• Convexity/parasagittal = seizures, hemiparesis
• Basisphenoid, diaphragma sellae = visual field defects
• Cavernous sinus = cranial nerve deficit(s)
• Frontal = anosmia

13. Imaging Features
• Best diagnostic clue
– Dural-based enhancing mass → cortical buckling, trapped CSF/vessels
in "cleft" between tumor and brain
• Location
– Supratentorial (90%)
• Parasagittal/convexity (45%), sphenoid ridge (15-20%)
• Olfactory groove (5-10%), parasellar (5-10%)
• Other (5%): Intraventricular, optic nerve sheath (ONSM), pineal region
• Rare: Intraparenchymal without dural attachment
– Infratentorial (8-10%): CPA most common
– Extradural (mostly intraosseous, calvaria) > 2%
– Extracranial (head/neck)
• Most common: Paranasal sinuses
• Less common: Nasal cavity, parotid, skin
– Multiple meningiomas: Seen in 1-9% of cases

14. CT Findings
• NECT
– Sharply circumscribed smooth mass abutting dura
• Hyperdense (70-75%), isodense (25%)
– Hypodense (1-5%), fat density (rare lipoblastic subtype)
• Calcified (20-25%)
– Can be diffuse, focal, sand-like ("psammomatous")
– "Sunburst," globular, rim patterns
– Calcification correlates with slow growth in asymptomatic meningiomas
• Necrosis, cysts, hemorrhage (8-23%)
– Trapped CSF pools, cysts in adjacent brain common
– Peritumoral hypodense vasogenic edema (60%)
– Bone CT
• Hyperostosis, irregular cortex, ↑ vascular markings

15. • CECT
– > 90% enhance homogeneously, intensely
• CTA
– May be helpful prior to DSA, embolization
– Delineates arterial supply, venous drainage

17. Axial CECT in a 26-year-old pregnant woman with sudden visual
loss shows an enhancing suprasellar mass (white solid arrow).

18. Axial CECT in a patient with primary optic nerve sheath meningioma shows
marked enhancement along the left optic nerve, described as a "tram-track"
sign (black solid arrow).

19. Axial CECT shows multiple well-delineated, right-sided extraaxial
masses (white solid arrow) that were moderately hyperdense on
NECT (not shown) and enhance strongly.

20. MR Findings
• T1WI
– Typically iso- to slightly hypointense with cortex
– Necrosis, cysts, hemorrhage (8-23%)
– Look for gray matter "buckling"
• T2WI
– Variable ("sunburst" pattern may be evident)
– 8-23% of intratumoral cysts (common; can be almost microcystic),
hemorrhage (rare)
– Best sequence for
• Visualizing CSF/vascular cleft between tumor, brain (80%)
• Identifying vascular flow voids (80%)
• Predicting "hard" meningioma at surgery (hypointense)

21. • FLAIR
– Hyperintense peritumoral edema, dural tail
• DWI
– DWI, ADC maps for TM variable in appearance
– Lower ADC in MM and AM compared to TM

22. • T1WI C+
– > 95% enhance homogeneously, intensely
– Dural tail (35-80% of cases) nonspecific
• Other neoplasms (schwannoma, adenoma, metastases), nonneoplastic
dural-based masses
– En plaque: Sessile thickened enhancing dura
• MRV
– Evaluate sinus involvement
• MRS
– Elevated levels of alanine at short TE
• Triplet-like spectral pattern at 1.3-1.5 ppm (overlapping of Ala, Lac)
• Elevated Glx alfa/glutathione

28. Angiographic Findings
– "Sunburst" or radial appearance
• Dural vessels supply lesion core
• Pial vessels may be parasitized, supply periphery
– Prolonged vascular "stain"
– Venous phase vital to evaluate sinus involvement

30. Thank you