Odontogenic tumours ADENOMATOID ODONTOGENIC TUMOR Adenoameloblastoma Ameloblastic adenomatoid

Odontogenic tumours

ADENOMATOID ODONTOGENIC TUMOR “Adenoameloblastoma” “Ameloblastic adenomatoid tumor”

Histopathological definition WHO definition: “Tumor of odontogenic epithelium with duct like structures and with varying degrees of inductive change in C. T. The tumor may be partly cystic, in some cases solid lesion may be present as masses in the wall of large cyst. Generally believed the lesion is not a neoplasm”

The histogenesis of AOT is still uncertain and sometimes categorized as a hamartomatous lesion. The tumor is sometimes referred as Two Third's tumor because it occurs in the maxilla in about 2/3 cases, about 2/3 cases in young females, 2/3 case associated with impacted tooth, 2/3 case affected tooth is canine

PATHOGENESIS Philipsen et al theorized that the gubernaculum dentis may be implicated in the development of AOT It consists of a fibrous band (gubernacular cord) running in the bony channel (gubernacular canal) that connects the pericoronal follicular tissue of the successional tooth with the overlying gingiva, and opens on the alveolar bone crest behind the deciduous predecessor. Gubernaculum dentis contains a Remnants of dental lamina AOT may arise from these epithelial residues in close proximity to the crown of a permanent tooth, and some of them can move during tooth eruption along the gubernacular canal

CLASSIFICATION • Based on clinical & radiographic findings Central/ Intraosseous Follicular Peripheral Extrafollicular Associated with No association with crown of embedded teeth

1. Follicular (F) • Located around crown & covers part of root of impacted 2. Extrafollicuar (E) • E 1: no relation to tooth structure • E 2: interradicular, adj roots diverge • E 3: superimposed at root apex • E 4: superimposed at mid root level 3. Peripheral (P)-slight erosion of bone crest

CLINICAL FEATURES • Incidence • represents 3– 7% of all odontogenic tumors • AGE - 2 nd decade • GENDER-F: M 1. 9: 1 • LOCATION • maxilla. > mandible • Anterior region –associated with impacted canine

Clinical presentation Usually asymptomatic Slow progressive growth Displace adjacent teeth Asymmetric facial swelling Peripheral variant: sessile mass on facial gingiva, painless

RADIOGRAPHIC FEATURES • Central AOT’s: well demarcated unilocular Radiolucency with smooth corticated border In follicular type, Radiolucency associated with crown & part of root of unerupted tooth In extrafollicular type, Radiolucency found b/w, above or superimposed on roots of erupted perm teeth

In 65% radiolucencies shows discrete radiopacities formed by calcification. SNOW FLAKE APPEARANCE • Peripheral lesions: erosion of alveolar bone crest

GROSS • Roughly spherical with a well defined fibrous capsule • Cut surface: shows solid tumor mass or One or more cystic spaces • When associated with an impacted tooth attachment of the lesion will be beyond cemento enamel junction (feature to differentiate from dentigerous cyst which will be attached to CEJ)

Histopathological features AOT is composed of epithelial cells: polyhedral or spindle-shaped or ameloblast like cells , arranged to form different patterns like island, sheets, strands, whorled mass, rosettes, duct-like pattern or convoluted pattern. One of the characteristic features is duct-like or tubular arrangement of ameloblast like cells (therefore the name AOT) The ameloblast like cells have nucleus arranged at the periphery away from the central space which may contain eosinophilic material.

Amorphous eosinophilic material also may be found in the midst of cells arranged as nests. Foci of calcification also may be scattered through out the tumor. Connective tissue is scanty.

Adenomatoid odontogenic tumor Rosettes of tumor cells Eosinophilic (amyloid-like) material Polyhedral cells arranged to form nests Duct-like structures lined by ameloblast-like cells Foci of calcified material Convoluted pattern formed by tumor cells Scanty connective tissue stroma

Polyhedral cells arranged to form nests

• Within cellular areas are tubular or duct like structures - Lined by single row of columnar cells with nuclei polarized away from the lumen Duct-like structures lined by ameloblast-like cells

AOT tumour islands with calcifications

DIFFERENTIAL DIAGNOSIS Dentigerous cyst OKC COC Ameloblastoma CEOT Odontoma -

TREATMENT & PROGNOSIS • Enucleation & curettage • Good prognosis • Recurrence is rare

CALCIFYING EPITHELIAL ODONTOGENIC TUMOR • CEOT, Pindborg tumour • is a rare, aggressive, benign odontogenic tumor of epithelial origin • accounting for only about 1% of all odontogenic tumors • First described by Pindborg in 1955 • Biologic behaviour of CEOTis variable, ranging from very slight to moderately invasive

DEFINITION Locally invasive epithelial odontogenic neoplasm, characterized by the development of intraepithelial structures, probably of amyloid like nature which may become calcified and which may liberated as the cells break down. ” (WHO 1992)

PATHOGENESIS • Epithelial cells of Pindborg’s tumor are derived from stratum intermedium layer of the enamel organ in tooth development • May arises from remnants of dental lamina

CLINICAL FEATURES • AGE: 3 RD – 5 TH DECADE • No sex predilection • LOCATION: Mandible (2: 1) Premolar- Molar region The rare peripheral type - in an anterior gingiva

Clinical presentation • Present as a slow-growing asymptomatic swelling often associated with an impacted tooth. • Grows by infiltration, producing cortical expansion, tooth movement, and root resorption • In maxilla: nasal congestion, epistasis & headache.

Radiographic features • Well defined & circumscribed unilocular or multilocular radiolucency • Demonstrates a mixture of small& large multilocular radiolucency -“honey comb” or “soap bubble” in appearance • More mature lesions exhibit a mixed radiolucent & radiopaque appearance • Radio-opacities from the calcifications resemble-“driven snow” appearance

Driven snow” appearance

GROSS • Size 1 - 4 cm • Grayish white – yellow to tan pink • Cut surface shows calcified particles – “crunching sound” while cutting

Histopathology Composed of islands, sheets or strands of polyhedral epithelial cells in a fibrous stroma. Cell outlines are distinct with prominent intercellular bridges Nuclei show considerable variation with giant nuclei and pleomorphism observed , mitotic figures are rare Areas of amorphous, eosinophilic, hyalinized extracellular material may be scattered throughout. Calcifications may be noted as well as amyloid-like material that may be in the form of concentric rings called ‘Liesegang ring’ of calcification.

Calcifying epithelial odontogenic tumor Noninflamed fibrous stroma Liesegang rings of Calcification Sheets of polyhedral cells with hyperchromatic nucleus and prominent intercellular bridges Amyloid like material

Sheets of polyhedral cells with hyperchromatic nucleus and prominent intercellular bridges Amyloid like material Calcification

Epithelial cells in sheets and islands dispersed throughout the connective tissue matrix along with numerous circular ring like calcifiactions

Polygonal squamous epithelial cells exhibiting distinct intercellular bridges (black arrow) along with cellular and nuclear polymorphism (white arrows), and areas of irregular calcification and eosinophilic material.

DIFFERENTIAL DIAGNOSIS • Dentigerous cyst • Okc • Central giant cell granuloma • Coc • Ossifying fibroma

TREATMENT • Surgical curettage & enucleation • 10 – 20% is reported • Enblock resection • Recurrence is rare

SQUAMOUS ODONTOGENIC TUMOR • DEFINITION “Benign but locally infiltrative neoplasm consisting of islands of well differentiated squamous epithelium in a fibrous stroma. The epithelial islands occasionally show foci of central cystic degeneration. ” (WHO) SOT was first described by Pullon et al. (1975)

Pathogenesis SOT may develop from the rests of Malassez, gingival surface epithelium remnants of the dental lamina.

Clinical features AGE: M: F 3 RD decade 1. 4 : 1 LOCATION: Peripheral/central Mandible: Premolar – Molar region Maxilla: Incisor – Canine region Clinical presentation • Often asymptomatic • May present with symptoms of pain and tooth mobility. • swelling of the gingiva

RADIOGRAPHIC FEATURE • Triangular-shaped Unilocular radiolucency between the roots of adjacent teeth • Extensive SOTs may present a multilocular pattern. • Peripheral variant may produce some ‘saucerization’ of the underlying bone RADIOGRAPHIC D/D Occurrence between ROOTS: • Lateral Periodontal Cyst, Globulomaxillary Cyts

Histopathology • • Well differentiated squamous epithelial islands Islands varying size & shape Peripheral cells: low cuboidal / flat Epithelial islands may undergo central microcystic degeneration • Stroma is mature fibrous tissue without inflammation

• central microcystic degeneration Squamous epithelial islands mature fibrous tissue

TREATMENT • Conservative surgical treatment • Recurrence is rare