This document discusses meningioma, a benign tumor that arises from meningothelial cells of the arachnoid membrane. It can occur in locations other than the skull base, such as the orbit, nasal cavity, paranasal sinuses, and soft tissues. Meningiomas are classified by their WHO grade, from grade I-IV, with higher grades indicating a higher rate of recurrence and more aggressive behavior requiring radiation therapy. Common subtypes include syncytial, fibroblastic, transitional, psammomatous, secretory, microcystic, angioblastic, atypical, clear cell, choroid, anaplastic, and rhabdoid meningiomas.

1. Meningioma
Dr. Naila Awal

2. • Benign tumor
• Arise- Meningothelial cells of arachnoid
• Site-
other than skull base
• Orbit
• Nasal cavity
• Paranasal sinuses
• Skull bone
• Soft tissue of glabella

3. Morphology
Gross-
• Rounded/ oval shaped
• Sometimes they grow in diffuse sheet like pattern
• bosselated /polypoid
• Usually encapsulated.
• Calcification
C/S-
• Firm
• Fibrous to gritty, whorling pattern
• May contain psammoma bodies.

4. Types
• WHO grade-I/IV –
Low rate of recurrence.
• WHO grade-II/IV-
High rate of recurrence
More aggressive
Need RT
• WHO grade-III/IV-
High chance of recurrence

5. WHO grade-I/IV
• Syncytial/ Meningothelial-
Whorl cluster
Meningothelial cell

6. Fibroblastic type
Elongated cell
With abundant
fibroblast

7. Transitional type
Meningothelial &
fibroblastic picture
Courtesy-pathology web

8. Psammomatous meningioma
• Psammoma body is formed from calcification
of syncitial nest of meningothelial cell.
Courtesy-pathology web

9. Secretory meningioma
• Presence of small round cytoplasmic
Inclusion
Courtesy-pathology outline

10. Microcystic meningioma
• Loose spongy appearance

11. Angioblastic meningioma
• Blood vessels are separated by closely packed cell
with ill defined cytoplasm and oval or fusiform nuclei.
• Highly vascular neoplasm

12. WHO grade-II/IV
• Atypical meningioma
Mitosis- 4 or 4+ /10hpf
Features- at least 3 atypical features should be present
Hypercellularity
Small cell with N:C ratio
Prominant nucleoli
Paternless growth
Necrosis

13. Clear cell meningioma
• Very unusual.
• Glycogen rich.

14. Choroid meningioma
Chordoma-like growth of
tumor cells in a
myxoid matrix.
Courtasy-frontalcortex

15. WHO grade-III/IV
• Anaplastic meningioma
Mitosis->20/10hpf

16. Papillary meningioma
Pleomorphic cell arranged around
fibrovascular core.
mitosis

17. Rhabdoid meningioma
Sheets of rhabdoid cells with eccentric nuclei,
prominent hyaline eosinophilic cytoplasm
containing intermediate filaments.