for oral radiology of dentistry student

1. 1

2. 2

3. Nonodontogenic benign tumors of neural origin :
Neurilemoma (Schwannoma ):
Disease Mechanism:
• a tumor of neuroectodermal origin
• arising from Schwann's cells that make up the inner layer covering the
peripheral nerves
• Although rare, it is the most common intraosseous nerve tumor.
• No potential for malignant transformation

4. Clinical Features:
• grow slowly
• can occur at any age (but most commonly arise in the second and third
decades)
• occur with equal frequency in males and females
• The mandible and sacrum are the most common sites
• These lesions cause few symptoms other than those related to the location
and size of the tumor.
• The usual complaint is swelling.
• Although pain is uncommon unless the tumor encroaches on adjacent
nerves, paresthesia may arise, especially with lesions originating in the
inferior alveolar canal.
• Pain, when present, usually develops at the site of the tumor; if paresthesia
occurs, it is felt anterior to the tumor.

5. Imaging Features:
Location:
• most often involve the mandible, with less than 1 in 10 cases occurring in the maxilla.
• The tumor most often is located within an expanded inferior alveolar nerve canal
posterior to the mental foramen
Periphery:
• slow growth rate, the margins of these tumors are well defined
• usually corticated as they expand the cortical walls of the inferior alveolar canal.
• Small lesions may appear cystlike but more commonly are fusiform in shape as the tumor
expands the canal.
Internal Structure: uniformly radiolucent.
Effects on Surrounding Structures:
• enlargement of the mandibular foramen or the mental foramen.
• outer cortex of the canal is maintained
• expansion of the canal is usually localized with a definite epicenter unless the lesion is
large.
• The expanding tumor may cause root resorption of adjacent teeth

6. Differential Diagnosis:
Hemangioma
arteriovenous (A-V) fistula
malignant lesion
Treatment :
Excision
do not recur if …
A capsule usually is present, facilitating surgical removal

9. Neuroma (Amputation neuroma & traumatic neuroma )
The original nerve damage may be the result of mechanical or chemical
irritation of the nerve caused by
Fracture
orthognathic surgery
removal of a tumor or cyst
extrusion of endodontic cement
dental implants
tooth extraction
overgrowth of severed nerve fibers
abnormal proliferation of scar tissue

10. Clinical Features:
• slow-growing
• reactive hyperplasias that seldom become large, rarely exceeding 1 cm
• They may cause various symptoms, including severe pain resulting from
pressure applied as the tangled mass enlarges in its bony cavity or as the
result of external trauma.
• The patient may have reflex neuralgia, with pain referred to the eyes, face,
and head.

11. Imaging Features(relate to the extent and shape of the proliferating mass of neural tissue):
Location:
mental foramen, followed by the anterior maxilla and the posterior mandible.
Periphery:
• well-defined, corticated borders.
• in various shapes, depending on the amount of resistance to expansion
offered by the surrounding bone.
• In the mandible, the tumor usually forms in the mandibular canal.
Internal Structure: totally radiolucent.
Effects on Surrounding Structures:
expansion of the inferior alveolar nerve canal may occur

13. Neurofibroma (Neurinoma ) :
Disease Mechanism:
moderately firm
Benign
well-circumscribed
caused by proliferation of Schwann's cells in a disorderly pattern that
includes portions of nerve fibers, such as peripheral nerves, axons, and
connective tissue of the sheath of Schwann.
As neurofibromas grow, they incorporate axons. In contrast,
neurilemomas are composed entirely of Schwann's cells and grow by
displacing axons.

14. Clinical Features:
• The central lesion of a neurofibroma may be the same as the multiple
lesions that develop in von Recklinghausen's disease.
• occur at any age but usually are found in young patients.
• Neurofibromas associated with the mandibular nerve may produce
pain or paresthesia.
• Neurofibromas also may expand and perforate the cortex, causing
swelling that is hard or firm to palpation

15. Imaging Features :
Location:
mandibular canal, in the cancellous bone, and below the periosteum.
Periphery:
• As with neurilemomas, the margins of the radiolucency in neurofibromas
usually are sharply defined and may be corticated.
• despite the benign nature and slow growth of the neurofibroma, some of
these lesions have indistinct margins.
Internal Structure:
usually appear unilocular but occasionally may have a multilocular
appearance.
Effects on Surrounding Structures: A neurofibroma of the inferior dental
nerve shows a fusiform enlargement of the canal

16. Differential Diagnosis: Differentiation from other types of neural
lesions may be impossible.
Treatment:
Solitary central lesions that have been excised seldom recur.
it is wise to reexamine the area periodically because these tumors are not
encapsulated, and some undergo malignant change.

19. Neurofibromatosis(von Recklinghausen's disease):
Disease Mechanism:
• a syndrome consisting of cafe au lait spots on the skin; multiple
peripheral nerve tumors; and various other dysplastic abnormalities of
the skin, nervous system, bones, endocrine organs, and blood vessels.
• The two major classifications are:
1. neurofibromatosis 1 (NF1), a generalized form
2. NF2, a central form.

20. Clinical Features:
• one of the most common genetic diseases, occurring in 1 : 3000 births
• The peripheral nerve tumors are of two types, schwannomas and
neurofibromas.
• Some manifestations are congenital, but most appear gradually during
childhood and adult life.
• Cafe au lait spots become larger and more numerous with age; most
patients eventually have more than six spots larger than 1.5 cm in
diameter.
• Other skin lesions include freckles; soft, pedunculated, cutaneous
neurofibromas; and firm, subcutaneous neurofibromas.

21. Imaging Features:
• enlargement of the coronoid notch in either or both the horizontal and the vertical
dimensions
• an obtuse angle between the body and the ramus
• deformity of the condylar head
• lengthening of the condylar neck
• lateral bowing and thinning of the ramus, as seen in basal skull views
• Changes in mandibular morphology can continue to increase in severity through the
second decade.
• enlargement of the mandibular canal and mental and mandibular foramina
• increased incidence of branched mandibular canal.
• Erosive changes to the outer contour of the mandible and interference with normal
eruption of the molars
• Abnormal accumulations of fatty tissue within deformities of the mandible have been
observed in images produced by MDCT imaging

23. 23