Oropharynx and Oral Cavity Flashcards
Leukoplakia
- Hyperkeratotic (white) plaque / patch of mucosa
- Clonality and representing precursor lesion to squamous cell carcinoma
- Approximately 40% of leukoplakias exhibit keratinizing dysplasia
- Remainder are characterized by hyperkeratosis alone
- Annual malignant transformation rate is 3%
- Predicted by presence of dysplasia on biopsy; increasing duration, increasing size and nonhomogenous appearance also associated with malignant transformation
- Non-frictional / reactive exhibits a malignant transformation rate of approximately 5%
- Associated with smoking / smokeless tobacco, alcohol and areca nut (betel quid) use
- HPV associated with only a very small percentage of cases
Micro:
* Hyperkeratosis / parakeratosis
* Epithelial atrophy or hyperplasia with bulbous rete ridges
* Basal cell hyperplasia with nuclear hyperchromasia or increased nuclear cytoplasmic ratio, variable suprabasal or atypical mitoses, dyskeratosis or glassy cytoplasm, dyscohesion
* Approximately 33% of dysplasias are characterized by an inflammatory infiltrate and should not be misdiagnosed as lichen planus
* Leukoplakia without dysplasia exhibits hyperkeratosis with no histologic features of a frictional / reactive process but is otherwise less well characterized
* Often superinfection with candida
Erythroplakia
- Any lesion of the oral mucosa that presents as bright red velvety plaques –> Dilated superficial vessels
- Irregular in outline, but clearly demarcated from adjacent normal epithelium
- Surface may be nodular
- May co-exist with areas of leukoplakia
- Malignant change in erythroplakia is 17x higher than in leukoplakia
- Histologically associated with invasive carcinoma in 50% cases
Lobular capillary hemangioma
- Rapidly growing
- Often located on sites of frequent trauma like the face, lips, mucosa and fingers
- Treatment usually involves shave removal with electrodesiccation or surgical excision; may recur following treatment.
Macro:
* Bright red papule that is often pedunculated or polypoid on the skin or mucosa
* Lesion frequently ulcerates and bleeds
Rare presentations include:
* Multiple lesions with satellite formations
* May occur within a pre-existing capillary malformation, such as a port wine stain
* Skin colored nodule if present in the deep dermis, subcutaneous tissue or intravascularly
Micro:
* Frequently exophytic or polypoid, though may also be sessile
* Lobules in the dermis that contain numerous capillary sized vessels
* Lobules are separated by fibrous septa or trabeculae, especially in older lesions
* Stroma is often edematous and more mucinous in early lesions, becoming more fibrotic with time
* Epidermal collarette is commonly observed
* Cytologic features include bland endothelial cells that may be plump;
* Mitotic figures may be frequent
* Fibroblasts and pericytes are also present
* Ulceration at the surface of the lesion is common
* Granulation tissue may be present at the surface of ulcerated lesions
* Secondary mixed cell infiltrate with lymphocytes and neutrophils is common
IHC:
ERG
CD31
CD34
FLI1
Factor VIII –> Von Willebrand
SMA (stains pericytes)
Radicular Cyst
- AKA periapical cyst
- Inflammatory type odontogenic cyst associated with the root of a nonviable (necrotic) tooth
- Caused by infection of the dental pulp by caries or trauma
- Lined by nonkeratinized stratified squamous epithelium, derived from rests of Malassez
- Most common location: anterior maxilla
- Second most common location: posterior mandible
Macro:
* Surgical specimens usually consist of multiple, irregular tissue fragments
* Possible minute bone fragments
* All (nontooth) tissue should be submitted for histologic examination to definitively confirm the diagnosis
Micro:
Epithelial lining
* Lined by nonkeratinizing stratified squamous epithelium of variable thickness
* Can have limited areas of keratinization, goblet cells or scattered ciliated cells
* Rushton hyaline bodies can occur within the epithelium (not necessary for diagnosis, not specific to radicular cyst)
Fibrous capsule
* Varying thickness with acute or chronic inflammatory cells
* Plasma cells may be particularly prominent
* Foamy histiocytes may also be present
Additional features possible:
* Cholesterol clefts
* Pulse granuloma
* Bacterial colonies
* Foreign material related to prior dental treatments
* Portions of bone, tooth or tooth root
Dentigerous Cyst
- Dentigerous cyst is a developmental odontogenic cyst
- Originates from the separation of the dental follicle from around the crown of an unerupted tooth
- Shows an epithelial lining attached to the cementoenamel junction
- Second most common odontogenic cyst
- May clinically present as a missing tooth
- AKA Follicular cyst
- Excellent prognosis, almost never recurs with complete enucleation
Micro:
* Cyst lined by stratified squamous epithelium in direct continuity with enamel epithelium, which covers crown of unerupted tooth.
* No inflammation in cyst wall.
Odontogenic keratocyst
- Intraosseous origin, maxilla or mandible
- Cystic strips of nonneoplastic, nondysplastic epithelium with a fibrous cyst wall
- Epithelial lining composed of parakeratinized stratified squamous epithelium with a hyperchromatic basal cell layer
- Lesion is intraosseous (within maxilla or mandible)
- May extend beyond bone borders into maxillary sinus, nasal floor or submucosa to mimic a peripheral lesion)
- Treatment is surgical
- With surgical enucleation, risk of recurrence is 20 - 30%
Micro:
* Uniform epithelial lining 6 - 8 cells thick lacking rete ridges
* May have artifactual clefting between epithelium and underlying fibroconnective tissue
* Epithelium is characterized by palisaded hyperchromatic basal cell layer composed of cuboidal to columnar cells
* May have areas of budding growth from the basal cells
* Luminal surface has wavy (corrugated) parakeratotic epithelial cells
* Lumen may contain keratinaceous debris
Molecular:
* Sonic hedgehog pathway alterations are common, specifically PTCH1 inactivating mutations
* BRAFV600E
* Multiple tumours seen in Naevoid Basal Cell Carcinoma syndrome/Gorlin Syndrome
Calcifying epithelial odontogenic tumor
- Also known as Pindborg tumor
- No sex predilection
- Wide age range (4 - 90 years old)
- Average age of 40 years
- Clear subtype appears to arise in a slightly older patient population and shows a female predominance
- 11% are peripheral
- 60% are associated with unerupted tooth, often mandibular molar
- ~60% are in the mandible
Micro:
* Sheets, nests or cords of polyhedral cells often with nuclear pleomorphism
* Mitotic figures are rare or absent
* Nuclei may be hyperchromatic, angular or crinkled
* Distinct cell borders often with prominent intercellular bridges (prickles)
* Amorphous, congophilic eosinophilic amyloid
* Amyloid may calcify, forming masses or Liesegang rings (round basophilic calcifications with concentric laminations)
* Pseudoglandular structures and cystic spaces have been described
IHC
Cytokeratins, CK5/6,
p63, p40
Amyloid highlighted by Congo red with apple green birefringence
Clear cell subtype has varying amounts of PAS positive, diastase labile accumulation
Calcifying odontogenic cyst
- Calcifying odontogenic cysts are located most commonly in the anterior regions of jaws
- Microscopically calcifying odontogenic cysts contain an ameloblastoma-like epithelial lining containing ghost cells that may calcify
- Calcifying odontogenic cysts are associated with β catenin (CTNNB1) mutations
- Treated by enucleation and curettage
Adenomatoid odontogenic tumor
- Benign, rare tumor of odontogenic origin
- Most common in the anterior region of the jaws in young female patients associated with impacted teeth
- Anterior maxilla is the most affected (66.6%)
- ~42% of cases are associated with impacted maxillary canines
Macro:
* Thick fibrous capsule
* Small calcifications give cut surface a gritty
Micro:
* Epithelium may appear nodular, trabecular, cribriform and form duct-like structures
* Cells may be spindly, cuboidal or columnar with the nuclei palisading away from the lumen
* Dystrophic calcification
* Lesion is enclosed in a thick capsule
* Calcifications may be seen
Odontoma
- Mixed epithelial and mesenchymal tumor-like malformation (hamartoma) composed of dental hard and soft tissues.
- Subdivided into compound odontoma and complex odontoma
- The most common odontogenic tumor
- Can obstruct the path of erupting teeth
Molecular:
* Odontoma-dysphagia syndrome
* Schimmelpenning-Feuerstein-Mims syndrome
* Familial adenomatous polyposis
* Encephalocraniocutaneous lipomatosis
* Gardner syndrome
Micro:
General:
* Can have scant or occasional ghost cell formation, can cause confusion with COC (CCOT / Gorlin cyst) Calcifying cystic odontogenic tumor (CCOT)
* Dental hard tissues; dentin and enamel
* Bone is not a dental hard tissue
Compound:
* Histologically similar to the layering of normal tooth in the relation of dentin, enamel matrix and pulp
Complex:
* More disorganized or haphazard arrangement of pulpal tissues, enamel or dentin
Treatment:
* Peripheral odontomas usually treated by excision.
* Central (intraosseous) complex and compound odontomas –> enucleation and curettage
Peripheral giant cell granuloma
- Reactive gingival mass resembling pyogenic granuloma
- Pushes teeth aside
- May erode alveolar bone or involve periodontal membrane
- Arises from periodontal ligament enclosing root of tooth
- Central giant cell granuloma: similar to peripheral giant cell granuloma but multiloculated
- Usually women, 30s to 50s, although may involve children or elderly patients without teeth
Ameloblastoma
- Odontogenic epithelial neoplasm characterized by slow, expansile growth
- Classified as a benign neoplasm
- Behaves in a locally aggressive manner with a tendency to recur
- Most commonly occurs in mandible
- Multiple microscopic variants
- Broad age range, narrowed somewhat by tumor type:
- Conventional type: peak incidence in fourth to fifth decades of life
- Unicystic type: peak incidence in second to third decades of life
- Extraosseous / peripheral type: peak incidence in fifth to seventh decades of life
- ~80% cases occur in mandible
- ~20% cases occur in maxilla
Macro:
* Solid and cystic areas
* White to grey
* Little haemorrhage and no necrosis
* Cysts contain clear to yellow fluid
Micro:
* Conventional type has at least 6 histopathological patterns:
* Single patterns may predominate within a given lesion, often mixed with 1 or more patterns
* Microscopic pattern has no documented prognostic significance
* Most important prognositic feature is presence or absence of infiltration.
* Follicular: most common subtype; islands of odontogenic epithelium in fibrous connective tissue; may be cystic; classic peripheral palisading and stellate reticulum-like areas
* Plexiform: cords and sheets of anastomosing odontogenic epithelial cells; classic peripheral palisading and reverse polarity not always obvious
* Acanthomatous: squamous metaplasia and variable keratinization of stellate reticulum-like cells
* Granular cell: stellate reticulum-like cells have granular eosinophilic cytoplasm; less commonly involves cells at periphery of nests
* Basal cell / basaloid: least common histologic subtype; islands of hyperchromatic basal cells without stellate reticulum-like areas
* Desmoplastic: compressed and angular islands of epithelial tumor cells with dense moderately cellular fibrous connective tissue or collagenous stroma; the formation of metaplastic bone trabeculae is also described
Molecular:
* Recurrent somatic and activating mutations in mitogen activated protein kinase (MAPK) pathway present in ~80% ameloblastomas
* BRAF V600E (most common mutation; at least 60%)
* RAS and FGFR2
IHC:
CK19 and CK14
CK5
CD56
Calretinin
BRAF V600E (VE1)
p63 and p40
