Mandibular Tumours

Mandibular tumours

Mandibular defect classification

Boyd’s HCL classification

H defects are lateral and of any length including the condyle and do not cross the midline.
L defects are as above but don't involve condyle
C defects consist of the entire central segment containing the four incisors and the two canines
Combination exist i.e. angle to angle defects LCL
o- neither skin nor mucosal defect
s - skin defect
m - mucosal defect
sm - skin and mucosa

Challenges

Soft tissue Reconstruction Only

In the past, L and H defects were reconstructed with soft tissue closure
Unopposed muscle pull on unresected remnant causes swing to the resected side, leads to cross bite.
This reduces the defect size but also leads to abnormal dental wear, caries, loss of function or concave appearance on the unaffected side

Central Segment reconstruction

Anterior arch defect - greatest aesthetic and functional problem and difficult surgical challenge
Frequently results in lip and chins ptosis in which the soft tissue slides of the reconstructed arch producing eversion of the lower lip and salivary incontinence.
Mandible tends to be pulled superiorly, especially in the edentulous which is not limited by occlusion:

Unopposed masseter and pterygoid action
The C segment has 4 mouth opening muscles (digastrics and geniohyoid) attached to it. When c segment resected these muscle attachment is lost or muscle lost in ablative procedure. . The mandible is then free of its anterior muscular tethering and is pulled upward by the unopposed action of the masseter and the pterygoids.
When not possible to preserve the C segment it is occasionally feasible to reattach the submental muscles to the reconstructed mandible

Chin Degloving
Mentum soft tissuedegloving should be reattached to avoid witch’s chin deformity
Lower facial nerve paralysis
Bilateral neck dissections often result in damage the lower branches of the facial nerve on both sides and exacerbates the lip ptosis.
Soft tissue contraction
If during reconstruction the floor of mouth dead space is not adequately filled with soft tissue the resulting contracture tends to distort the new bony reconstruction or draw the soft tissue inferiorly thus resulting in inferior displacement.

Mandibular pathology

Physiology

Amoloblasts – secrete enamel
Odontoblast – secrete dentin
Cementoblasts – secrete cementum
Fibroblast – periodontal membrane
Neural crest forms nearly all components of teeth - dentin, pulp, periodontal ligament and cementum, except enamel (develops from ectoderm)
Enamel
acellular (96% mineral), tapers off at the cementoenamel junction
dependant on underlying dentin for support
Dentin
70% mineral
Occupied by odontoblasts which secrete matrix and also mediate sensation
Pulp
Odontoblasts to make dentin
Nutrition
Sensation
Cementum
Calcified connective tissue covering the anatomic root
Anchors the periodontal ligament to the root of the tooth
Continuous cementum deposition maintains length of the tooth as compensation for occlusal wear
May be acellular or contain cementoblasts

Symptoms and signs

1)Swelling (fibrous dysplasia, cherubim, cysts and cancer)

2)pain (osteoradionecrosis, osteomyelitis and invasive cancer)

3)Numbness (neoplastic invasion of the V3)

4)Loosening of teeth (weakness of the socket by disease processes)

5)Oral mucosal involvement (mandibular sarcomas breaking out, mucosal carcinomas breaking in, osteoraionecrosis causing inflammation breakdown and bone exposure

Tumours of the mandible

Classification(Kramer)

1)Odontogenic

Cysts
Epithelial
radicular (periapical) cyst(55%)
dentigerous cyst (24%)
residual cyst (20%)
keratocyst (5%)
Benign Tumors
Epithelial
ameloblastoma (11%)
calcifying epithelial odontogenic tumor
adenomatoid odontogenic tumor
Mesenchymal
myxoma (3%)
benign cementoblastoma
odontogenic fibroma
Mixed
ameloblastic fibroma
ameloblastic fibroodontoma
odontoma
Malignant Tumors
Epithelial
malignant ameloblastoma
Mesenchymal
ameloblastic sarcoma

2)Nonodontogenic

Cysts
Epithelial
fissural median mandibular cyst
Nonepithelial
traumatic bone cyst
aneurysmal bone cyst
Benign Tumors
Fibrous dysplasia
cherubism
giant cell granuloma
osteoma
Malignant
Primary
osteosarcoma
chondrosarcoma
central mucoepidermoid carcinoma
Burkitt’s lymphoma
Secondary
metastatic carcinoma
SCC

Odontogenic tumors radiographic features

Radiolucent Lesions

ameloblastoma
ameloblastic fibroma
odontogenic fibroma
odontogenic myxoma
squamous odontogenic tumor
clear cell odontogenic tumor

Radiolucent with or without Radiopacity Lesions

adenomatoid odontogenic tumor
calcifying epithelial odontogenic tumor

Radiopaque with or without Radiolucency Lesions

odontoma
ameloblastic fibro-odontoma
ameloblastic odontoma

Odontogenic Cysts

Radicular cysts (apical cyst)

Most common cyst of jaw (55% of cysts)
Response to apical inflammation
may have sinus tract to oral mucosa or even skin

Radiographic features

Pulpless nonvital tooth
Small well defined periapical lucency

Treatment

Extraction, root canal
Low recurrence rate

Dentigerous cyst

25%of odontogenic cyst
Peak incidence in 2nd and 3rd decades
Fluid between reduced enamel epithelium and tooth crown
Surrounds unerrupted second and thirdmolars. Cysts have epithelial lining and vary from 2cm to expansible mass
May cause displacement of teeth and facial asymmetry
Can be locally destructive

Radiographic features

well-demarcated radiolucent lesion attached at an acute angle to the cervical area of an unerupted tooth

Treatment and prognosis

Enucleation or marsupialization.
6% recur
Possible malignant transformation – 20% of ameloblastomas arise from these cysts, also SCC and mucoepidermoid tumor

Keratocysts

5% of all jaw cyst
third most common odontogenic cyst and belongs in the differential diagnoses of any radiolucency of the jaws.
Affect all ages with peak in 2nd 3rd decade
M>F
50 % around third molar and ascending ramus
different from other cysts; they are aggressive and can be difficult to remove. OKCs can grow quite rapidly, and recurrences are frequent - grow in a multilocular bosselated fashion with daughter cysts that extend into the surrounding bone.
cysts are formed with a stratified squamous epithelium
5% have basal cell nevus syndrome, also known as Gorlin syndrome
hypertelorism, midface hypoplasia, relative frontal bossing and prognathism, mental retardation, multiple basal cell carcinomas, calcification of the falx cerebri, bifid ribs, palmar pitting (the pits later develop into basal cell carcinoma), and multiple OKCs.
Multiple OKCs are diagnostic for basal cell nevus syndrome until proven otherwise.
autosomal dominant inheritance and high penetration

Radiographic features

Mimics many cysts
Multiloculated with scalloped radiopaque borders
Marked cortical thinning and root resorption

Treatment

Enucleation with curettage for small cyst
aggressive and can be difficult to remove
60% recurrence with incomplete excision

Residual cysts

Incidence and features

Any odontogenic cyst that persists in bone after tooth is removed
20 % of odontogenic cysts

Clinical

Static or slowly enlarging asymptomatic or painful with inflammation

Etiology

From epithelial remnant of periapical granuloma (root abscess)

Radiol

Well circumscribed cyst in endentulous area

Treatment

Enucleation with low recurrence rate

Non-odontogenic Cysts

Fissural: median mandibular cyst

Rare; nonaggressive
thought to be derived from epithelium entrapped in the lines of fusion of the body process that forms the jaw and face
Cysts are line with stratified squamous epithelium and respiratory epithelium.
Midline symphyseal
Controversial from trapped epithelial remnants of mandibular arch fusion vs. peri odontal cyst
Nucleation; uncertain of prognosis due to rarity of lesion

Traumatic bone cyst

Features and incidence

Empty or fluid filled cavity associated with jaw trauma(50%)

Location

Mostly anterior mandible but also molar area

Clinical Presentation

Size extremely variable aymptomatic and found on routine associated with labial or buccal expansion teeth remaining vital

Etiology

Trauma with intramedullary hematoma

Radiographic

Smooth radiolucency with scalloped borders extending roots

Treatment and Prognosis

May resolve spontaneously curettage with possible bone grafting of low recurrence rate.

Aneurysmal bone cyst

Incidence

Rare in mandible benign expansile lytic lesion

Location

Body of mandible

Clinical presentation

Pain and swelling growth rate variable

Etiology

Possibly traumatic origin with localized alteration in hemodynamics or persistent connection between damaged vessels and hematoma possibly AV fistula
Expansile eccentric cyst with thin cortices; soap bubble or honeycomb appearance
Large vascular sinusoids (no bruit)

Radiographic

Multilocular radiolucency with cortical expansion

Treatment

Curettage or excision.
Recurrence rare

Odontogenic epithelial tumours

Ameloblastoma

may develop from any of the epithelial elements (e.g. dentigerous cyst, enamel organ, peridontal membranes)
benign but locally invasive
most common odontogenic tumor (11%)
peak incidence 4th – 5th decade
Propensity for rapid disfiguring growth and late recurrence

Location

80% in mandible, 20% in maxilla
Most commonly in molar area
Often associated with unerupted third molar

Clinical features

Slow growing painless swelling with or without a soft tissue mass
Size range from1-16 cm
Large lesions can cause facial asymmetry or displaced teeth and malocclusion
Can expand bone erode through it or produce pathological fracture

Radiology

Classic appearance – multilocular (soap bubble) radiolucency of posterior mandible
3 types

Unilocular (13%)
Round or ovoid appearance with no calcified or radioopaque components distinct border with slight marginal sclerosis, may have scalloped margins ; no periosteal reaction.
Often confused with odontogenic cysts
Multilocular (86%)
Honeycomb or soap bubble appearance ; marked expansion with cortical thinning and bony destruction
Peripheral (extraosseous – 1%)

Treatment

Curettage or enucleation not recommended due to 90 % recurrence
partial mandibulectomy or segmental resection with margins of normal bone recommended( recurrence rate -5% )
Radiotherapy palliative for unresectable tumours
Mets rare

Calcifying epithelial odontogenic tumours(Pindborg tumour)

Incidence /Features

Rare, locally aggressive tumour;
2% of odontogenic tumours
Bimodal incidence
Occurs in third to fourth decades

Location

Usually in Premolar and Molar area (in contrast to ameloblastoma)
Many associated with unerupted teeth

Radiology

Chief sign is cortical expansion in all directions
Radiolucent; poorly defined, noncorticated borders
Unilocular, multilocular, or “moth-eaten”
Driven-snow” appearance from multiple radiopaque foci

Treatment

Similar to ameloblastoma
Up to 14% recurrence reported

Adenomatoid odontogenic tumour

A well-circumscribed lesion derived from odontogenic epithelium that usually occurs around the crowns of unerupted anterior teeth of young patients
consists of epithelium in swirls and ductal patterns interspersed with spherical calcifications.

Incidence

Rare nonaggressive tumour
F>M 2:1
age <20

Location

anterior to canines and frequently associate with impacted or unerupted teeth
may be associated with cortical expansion

Clinical Presentation

low growing asymptomatic mandibular swelling
small 1.5 - 3 cm painless anterior tumour

Radiology

well-demarcated mixed radiolucent / opaque lesion often surrounds the crown of an impacted tooth

Treatment and prognosis

Conservative excision; low recurrence rate

Odontogenic mesenchymal tumours

Myxoma (fibromyxoma)

Locally aggressive - 3% of odontogenic tumours
primarily consisting of a mucoid ground substance with widely scattered undifferentiated spindled mesenchymal cells.
Peak incidence in second and third decades
Painless slow jaw enlargement

Location

Usuallyposterior mandible but rarely in condyle
progressive swelling with bony expansion; can cause malposition of teeth

Radiology

Margins variably demarcated
multilocular radiolucency soap bubble or honeycomb appearance

Treatment and prognosis

En bloc excision; recurrence rate - 25%

Odontogenic mixed tumours

Odontoma

Features and incidence

composed of aberrant tissue of all the dental elements likely a harmartoma
Common
All ages but mostly second decade

Location

Posterior mandible
Usually less than 1cm +/- larger

Clinical

Most are symptomatic but swelling may interfere with tooth eruption
From odontognic apparatus(i.e. Enamel, dentin and cementum)

Radiology

solid unilocular radiopaque mass surrounded by a thin radiolucent zone

Treatment

Early enucleation to prevent interference with tooth eruption
Low recurrence rate

Compound OdontomaCompound Odontoma

Malignant Epithelialodontogenictumors

Malignant ameloblastoma

Incidence and features

Rare tumour classified as an odontogenic carcinoma
Any age after first decade
Most commonly in men >50 years

Location

Generally same as ameloblastoma

Clinical Presentation

History of multiple unsuccessful treatments of benign but persistent odontogenic epithelial lesion
Pain swelling ulceration and paresthesia
Regional lymphadenopathy with mets to lung, liver vertebrae

Etiology

Arises from residual odontogenic apparatus or from transformation of an odontogenic cyst or ameloblastoma

Radiology

Poorly defined radiolucency with gross expansion and thinned cortices

Treatment

Full ontological screening, radical excision
Rare tumour thus ideal treatment difficult to define
radiorx and chemo rx are used
Poor prognosis

Non Odontogenic Benign tumors

Fibrous Dysplasia

Found in membranous facial bones of younger individuals and becomes less active with maturity

Incidence

Uncommon
First and second decades

Features

Fibro osseous lesion
Developmental derangement due to undiffentiated mesenchymal bone forming cells replacing normal lamellar by woven bone
Monostotic and polyostotic variants
Polyostotic associated with AlbrightsSyndrome

Location

Common in maxilla
Angle of mandible
Usually progressive unilateral swelling with variable facial asymmetry
Pain and decreased function with progressive deformity
Dentition can be shifted
Burns out after puberty

Radiology

Ground glass or orange peel appearance
Poorly circumscribed with diffuse borders
Pagetoid or cyst like appearance

Treatment

If required, definitive reconstruction when disease has burned out
Earlier intervention with partial resection, ,curettage or bony contouring indicated for pain and functional loss.
Rare malignant change post radio rx - thus not recommended
Prognosis generally good

Cherubism

Features and incidence

autosomal-dominant disorder of variable penetrance (100% penetrance in males)
Bilateral symmetrical maxilla and mandible swelling
Usually begins with eruption of secondary dentition (age 2-4)
stabilizes after the growth period, usually leaving some facial deformity and malocclusion.

Location

Entire body and ramus with sparing of condoles
Extends into alveolar process

Clinical presentation

Painless rapid early growth
Alveolar involvement causes shedding of deciduous teeth
Delayed eruption and malocclusion
maxillary fullness produces retraction of the lower eyelids increasing scleral show causing “cherubic Appearance”

Radiographic features

Bilateral well defined multilocular expansile radiolucenices
Becomes ground glass at end of growth
Cortical thinning or absence

Treatment

Generally resolves with age
Treatment individualized on amount of regression or deformity
Good prognosis if limited to mandible

Giant cell granuloma

Incidence and features

Uncommon
3-5% of benign jaw tumours
Neoplastic like reactive proliferation - locally aggressive
Multinucleated giant cells on histology
Younger age groups

Location

Typically symphyseal and bicuspid regions

Clinical

Intermittent variable growth
Pain may be dominant symptom

Radiology

Unilocualted or multiloculated well circumscribed

Treatment

Curettage of excision
Recurrence rare with complete excision

Osteoma

exophytic nodular growth of dense cortical bone on or within the mandible or maxilla in locations other than those occupied by exostoses.
benign skeletal neoplasm of unknown etiology that is composed of osteoid and woven bone.
hamartomatous proliferation
restricted to the craniofacial skeleton located either superficially or intraosseously
classic presentation is that of focal bone pain at the site of the tumor. The condition worsens at night and increases with activity, and it is dramatically relieved with small doses of aspirin.
often associated with Gardner syndrome

Treatment

surgically reducing osteoma to the level of the surrounding bone

Gardners Syndrome

Autosomal dominant with multiple osteomas, epidermal cysts, colon polyposis and pigmented lip macules

Location

Commonly lingual surface of mandibular body
Attached to cortical bone by a stalk

Treatment and prognosis

Usually not required
If symptomatic , local excision is sufficient with no risk of recurrence

Non odontogenic Malignant (Primary)

Burkitts Lymphoma

Features and incidence

Poorly differentiated B cell lymphoma
Most common childhood malignancy in east Africa
Mean age 7-9 yrs
Rare in north America with mean age 11-12 yrs
Fastest growing neoplasm

Location

80% of tumours found in all four jaw quadrants
Jaw less commonly involved in north American cases

Clinical presentation

Enlarges very rapidly shifting and exfoliating the teeth
Associated with adrenal , kidney and gonadal masses
Lymphadenopathy rare

Aetiolgy

Related to EBV

Genetic association

Link to malaria

Treatment and Prognosis

Chemotherapy

50 % relapse rate

Poorer prognosis if gonadal involvement

Non odontogenic malignant(secondary)

Squamous cell Carcinoma

Features and Incidence

30 % of head and neck cancers
M:F 2:1
Increasing female incidence due to smoking

Morphology

exophytic (best prog)
Ulcerative
Mixed

Histological variants

Basiloid (worst variant)
Verrucous - 5% of oral SCCs (better prognosis)

Location

Commonly arises in mucosa of posterior alveolar ridge, but can spread from any part of the oral cavity including the lips
35 -50 % have bone invasion histologically and radiographically at the time of diagnosis
Spread is through occlusal surface (gingiva and tooth socket) since the periosteum is considered an effective barrier to tumor spread
May extend along inferior alveolar nerve
10 %of oral sccs arise at alveolar ridge

Clinical

May present as an incidental finding or as advanced disease
Present with non healing ulcer, pain, loose tooth, poorly fitting dentures, difficulty with mastication or numbness in the inferior alveolar region
Weight loss common

Risk factors

Smoking 6x risk
Betel chewing increased risk when combined with tobacco
Alcohol 6x risk
Alcohol plus tobacco 15x risk
Malnutrition, iron, vitamin a and C deficiencies
Solar exposure - lips
Viral
Poor dentition
Genetic

Treatment

Initial screening

Hx and Ex

CXR and LFT

Ct for nodal and distant disease

MRI useful for soft tissue and perineural involvement

Bone scan if bone pain

Pan endoscopy

Consultation

H and N team
Oncologist
Nutritionalist

Modalities of treatment

Surgery
Radiotherapy
Chemotherapy
50 % reduction in cure rate with nodal involvement
Prognosis generally poor