1. NEURILEMOMA (SCHWANNOMA)
A benign encapsulated nerve sheath neoplasm composed of Schwann cells. They were first described by jose Verocay in 1908.

2. a benign neural neoplasm of Schwann cell origin
Schwann cell (neurilemma cell)……. A cell that forms the myelin sheath of a nerve fibre
During its development the cell wraps itself around the fibre.
relatively uncommon
although 25% to 48% of all cases occur in the head and neck region.
but only 1% show an intraoral origin

3. a slow-growing, encapsulated tumor that typically arises in association with a nerve trunk.
As it grows, it pushes the nerve aside

4. Usually asymptomatic
although tenderness or pain may occur in some instances.
most common in young and middle-aged adul
range from a few millimeters to several centimeters in size.
The tongue is the most common location for oral neurilemomas

5. Intraosseous examples
most common in the posterior mandible
unilocular or multilocular radiolucencies
Pain and paresthesia are not unusual

6. Histopathologic Features
usually an encapsulated tumor

7. spindle shaped cells having long twisted and wavy nuclei
two microscopic patterns in varying amounts:
(1) Antoni A and (2) Antoni B.
Antoni A tissue ………streaming fascicles of spindle shaped Schwann cells.
Antoni B tissue …… less cellular and less organized; the spindle cells are randomly arranged within a loose, myxomatous stroma.
(may represent degeneration of the cells )
Antoni B
looser areas
(blue arrows)
Antoni A
(black arrow)

8. Antoni B
Antoni A

9. consist of reduplicated basement membrane and cytoplasmic processes.
These cells often form a palisaded arrangement around central acellular ,eosinophilic areas (Verocay bodies).
consist of reduplicated basement membrane and cytoplasmic processes.
This peculiar alienation of cells of Schwann known as Verocay bodies, is not exclusive of schwannomas, and may be found in other mesenchymal tumors.

10. Verocay bodies
consist of reduplicated basement membrane and cytoplasmic processes.
axone
Typically,
neurites cannot be demonstrated within the tumor mass.
Verocay bodies.

11. S-100 protein was strongly reactive in the spindle cells

12. Treatment and Prognosis
The neurilemoma is treated by surgical excision, and the lesion should not recur.
Malignant transformation does not occur or is extremely rare.
Normal bone tissue and absence of lesion recurrence 5 years after surgery