Odontogenic tumors ib/endodontic courses

LEARNING OBJECTIVES
At the end of the lecture student should be able to
– Enlist clinical features,
– Enlist radiological features,
–Enlist histopathological features of
Ameloblastoma
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 Slow growing with few or
no signs in early stages
 Most commonly present
with chief complaints of
swelling and facial
asymmetry.
 The swelling is typically
asymptomatic, pain is an
occasional presenting sign.

Continued growth of the
tumor & enlargement of the
involved area may eventuate
in ulceration of the mucosa
overlying the lesion.
Small lesions tend to be
discovered more often on
routine radiographic
screening examinations
Local effects include tooth
mobility, occlusal alterations,
and failure of eruption of
teeth.

 Radiographically, the
intraosseous ameloblastoma
classically is described as a
multilocular or ‘‘soap-
bubble’’radiolucency.
 Other radiographic patterns
seen are
 Smooth bordered unilocular
radiolucency,
 A unilocular lucency with a
scalloped or lobulated
border,
 A poorly delineated mixed
lucentopaque lesion

 More than half of unilocular
lesions are reported to be
associated with an impacted
tooth, and the lesion typically is
found surrounding the crown of
the impacted tooth in a
dentigerous cyst type relationship

 The mandibular third molar
is the most commonly
involved tooth.
 Unilocular lesions
associated with an impacted
tooth also tend to be found
in significantly younger
patients compared with
patients with multilocular
lesions.
 Impacted teeth -15% to 40%
of all cases.

 Cylindrical / Fusiform swelling expanding bone
 Perforation of the cortex
 Greyish white/ Greyish yellow mass
 Readily cut containing no calcifications
 Some cases solid and in some cystic spaces may be
present
 Straw colored fluid / Semi solid material may be
present

 Two main patterns of ameloblastoma are recognized
 Follicular
 Plexiform
 Other Histopathologic subtypes of ameloblastoma are
recognized:
 Acanthomatous,
 Granular cell,
 Basal cell,
 Desmoplastic,

 Clear cell,
 Keratoameloblastoma
 Papilliferous ameloblastoma
 Hemangiomatous ameloblastoma
 Mucous cell differentiation

 The histologic subtype may have prognostic
implications for recurrence.
 The follicular type of ameloblastoma had the
highest rate of recurrence at 29.5%.
 The acanthomatous type of ameloblastoma showed
only a 4.5% recurrence rate.
 The plexiform subtype showed a 16.7% recurrence
rate.
 Recurrences documented in granular cell , basal
cell,& Desmoplastic subtypes

 Darkly staining periphery composed of
tall columnar cells
 Hyperchromatic nuclei.
 A small clear vacuole can be seen between the
nucleus & the basement
membrane.
It mimic the normal embryologic
development of the tooth bud at
the stage of enamel matrix
production.

 Most commonly encountered variant
 All of the core features of ameloblastoma are typically
present.
 The follicular ameloblastoma tends to grow primarily
in islands, however, the cords & strands are less
prominently present.
 The islands of tumor in the follicular ameloblastoma
can enlarge to sufficient size that central cystic
degeneration is seen.

 The central cells are typically polyhedral to spindle
shaped. When spindle shaped, they often have
angular nuclei and poorly defined cytoplasm, with
delicate fibrillar cytoplasmic processes that contact
adjacent cells
 Produces a loosely cohesive meshwork that
closely simulates the stellate reticulum seen in the
developing enamel organ.
 This fairly common characteristic of follicular
ameloblastoma is less prominently present in
many of the other histologic subtypes.

 May closely resemble the follicular type. It tends to
grow primarily in an island-like pattern.
 It differs from the follicular ameloblastoma in the
nature of the central cells within the tumor islands.
 In the acanthomatous ameloblastoma, squamous cells
replace the stellate reticulum-like cells. The squamous
cells nearly always show a tendency to keratinization

 Parakeratin typically is seen. This effect produces a
distinctive pink color change compared with the
deeply basophilic staining maintained in the
peripheral columnar cells.
 A layer of stellate reticulum-like cells that separates
the peripheral columnar cells from the central
squamous areas often is seen.
 Central cystic change can be seen in larger tumor
islands.

 Characteristic feature is the presence of granular
cells in the central portion of the epithelial
islands, strands, and cords
 The granular cells tend to be large and have an
oval to polyhedral outline. The nucleus is
displaced to the periphery of the cells.
 Prominent coarse granules pack and distend the
cytoplasm, imparting the distinctive appearance
responsible for the name of these cells.

 The granular cells sometimes show a sharply
delineated cell border, but most often the cell
membranes are poorly demarcated, and the
cytoplasm of adjacent cells merges imperceptibly.
 The cytoplasmic granules tend to stain weakly
eosinophilic
 A thin rim of stellate reticulum-like cells that
separates the granular cells from the peripheral
columnar layer may or may not be present.

 Clinical features- Slow growing, relatively
asymptomatic swelling presents with facial
asymmetry
 Radiological features- Soap bubble multilocular
radiolucency/unilocular (dentigerous cyst type),with
cortical expansion
 Histopathological features-Vicker’s & Gorlin criteria
 Various histologic variants of Ameloblastoma

 Text book of oral pathology Shafer's, 5 & 6th
edition
 Odontogenic Tumors & Allied Lesions Reichart/
Philipsen Ist edition
 Color Atlas of Oral Diseases Cawson, R. 2nd
edition
 Oral and Maxillofacial Pathology Neville, Brad W.
2nd
 Lucas’s Pathology Of Tumor’s of the Oral Tissues
 Cawson, R. A., Bennie, W. H 5th
edition

Odontogenic tumors ib/endodontic courses

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