8. Oral Pathology Flashcards
Histologic features of OKC
Cyst lined by thin layer of parakeratotic stratified squamous epithelium, which is usually 6-8 layers thick
Nevoid basal cell carcinoma syndrome (Gorlin syndrome)
-Multiple basal cell carcinomas
-Multiple OKCs
-Palmar and plantar pits
-Calcified falx cerebri
-Rib anomalies (bifid, missing, partially developed)
-Spina bifida
-Hypertelorism
-Enlarged head circumference due to frontal bossing
-Cleft lip and palate
Odontogenic tumors arising from odontogenic epithelium (6)
- Ameloblastoma
- Calcifying odontogenic cyst (Gorlin Cyst)
- Calcifying epithelial odontogenic tumor (CEOT)
- Adenomatoid odontogenic tumor (AOT)
- Squamous odontogenic tumor
- Clear cell odontogenic tumor
Odontogenic tumors arising from odontogenic mesenchyme (4)
- Central odontogenic fibroma
- Odontogenic myxoma
- Cementifying fibroma
- Cementoblastoma
Odontogenic tumors arising from BOTH epithelium and mesenchyme (4)
- Ameloblastic fibroma
- Ameloblastic fibro-odontoma
- Ameloblastic fibrosarcoma
- Odontoma
Ameloblastoma histological subtypes (5)
- Follicular pattern
- Plexiform pattern
- Acanthomatous pattern
- Granular cell type
- Desmoplastic type
Unicystic ameloblastoma subtypes
- Unicystic
- Intraluminal type
- Mural type
Fibro-Osseous Lesions
Disease process characterized by normal bone being replaced by fibrous tissue containing a mineralized product.
- Fibrous dysplasia
- Cemento-osseous dysplasia (COD)
MRONJ staging
Stage 0: non-exposed bone variant. Non-specific symptoms such as bone pain and unexplainable tooth pain. May have radiographic bone changes not attributable to other source.
Stage 1: exposed and necrotic bone or fistulae that probe to bone in asymptomatic patients with no evidence of infection
Stage 2: Exposed and necrotic bone or fistulae that probe to bone in symptomatic patients with evidence of infection
Stage 3: exposed and necrotic bone or fistulae that probe to bone in symptomatic patients with infection and one or more of the following:
- Exposed necrotic bone extending beyond the alveolus
- Pathologic fracture
- Extra-oral fistula
- Oral antral/oral nasal communication
- Osteolysis extending to the inferior border of the mandible or sinus floor.
Osteoradionecrosis of the jaw risk factors
- Radiation dose >60 Gy
- Primary tumor in tongue, FOM, alveolar ridge, retromolar triangle, or tonsil
- Higher stage cancer requiring ostectomy or mandibulectomy
- Periodontal disease, poor hygiene, dental extractions after radiation, alcohol use, tobacco use, and poor nutrition
Marx “3H theory” for ORN
Hypoxic-hypocellular-hypovascular tissue caused by radiation
How does HBO work?
Increases tissue oxygenation by stimulating angiogenesis. Also stimulates fibroblast proliferation and collagen formation, which leads to healing. The increased oxygen tension is bactericidal and bacteriostatic.
Marx HBO protocol for treatment of osteoradionecrosis
30 HBO dives (100% O2 breathed at 2.4 atmospheres for 90 minutes).
Re-evaluate patient after 30 dives. If improvement (decrease in exposed bone, granulation tissue formation, or re-mucosalization), patient completes full course of up to 60 total dives for full mucosal coverage.
If no improvement after initial 30 dives, patient advanced to stage II. This involves trans-oral debridement or sequestrectomy with primary mucosal repair. If healing progresses, patient completes up to 60 dives. If recurrent bone exposure, patient advanced to stage III.
Stage III, after 30 dives, patient undergoes resection to bleeding bone with primary wound closure and external fixation. Patient then dives until there is complete mucosal closure or a total of 60 accumulated dives.
HBO protocol for prevention of osteoradionecrosis
Patients that have received previous tumoricidal head and neck radiation should receive prophylactic HBO therapy prior to oral surgical procedures.
20 dives of HBO followed by 10 dives postoperatively.
4 major types of melanoma
- superficial spreading (most common, trunk + extremities)
- lentigo maligna (face + neck)
- nodular (trunk and extremities)
- acral lentiginous (rare, palms, soles, mucous membranes, nail beds. African or Asian descent. Most common ORAL form. Worse prognosis).
Breslow depth
Measure of prognosis of melanoma (most closely linked to primary tumor thickness vs. subtype).
Breslow depth greater than 1-4mm or with ulceration, sentinel lymph node biopsy is indicated.
For depths greater than 4mm, lymph node dissection should be considered.
Also dictates margin of resection:
Melanoma in-situ 0.5cm
<1mm 1cm
1.01-2.0mm 1-2cm
>2mm 2cm
How is cutaneous melanoma staged?
T = THICKNESS (mm)
TX (cannot be assessed)
T0 (no evidence of primary tumor)
Tis (melanoma in situ)
T1 (melanomas 1.0mm or less)
T2 (melanomas >1.0-2.0mm
T3 (melanomas >2.0-4.0mm)
T4 (melanomas >4.0mm)
(a without ulcaration, (b) with ulceration
N = No. OF METASTATIC NODES
NX (cannot be assessed)
N0 (no regional metastases)
N1 (one node)
N2 (two-three nodes)
N3 (four or more tumor-involved nodes)
M = METASTASES
M0 (no distant metastases)
M1a (metastases to skin, muscle or non-regional lymph nodes)
M1b (metastases to lung)
M1c (metastases to CNS)
(0) if LDH normal
(1) if LDH elevated
What are the risk factors for primary mucosal melanoma?
Unlike cutaneous counterpart, no association with UV exposure.
Inhaled and ingested carcinogens (smoking, formaldehyde).
Most common form of oral mucosal melanoma
Acral lentiginou smelanoma (maxillary alveolar ridge and hard palate)
How is mucosal melanoma staged?
TNM
T:
T3 mucosal disease. Limited to mucosa and underlying soft tissue regardless of greatest dimension.
T4a moderately advanced invading deep soft tissue, cartilage, bone or overlying skin
T4b very advanced involving brain, dura, skull base, cranial nerves, masticator space, carotid artery, prevertebral space, mediastinal structures.
N:
NX cannot be assessed
N0 no regional nodes
N1 regional node metastasis
M:
M0 no distant metastases
M1 distant metastases
How is primary mucosal melanoma treated
Complete surgical resection, wide dissection of 3cm.
Lymph node dissection on patients with evident regional metastasis. Even in absence of clinically evident nodes, sentinel node biopsy is useful.
Radiation therapy used if patient is poor surgical candidate or margins are inadequate. Ill-defined indications, but usually used only in advanced or recurrent disease.
Chemotherapy offered as palliative care. No increase in 5 year survival.
Basal cell carcinoma 3 subtypes
- Nodular (most common, shiny or pearlescent papules or nodules with telangiectasias, crusting over central depression or ulceration with rolled border).
- Superficial (second most common, scaly pink-red macules on trunk/extremities, least aggressive).
- Morpheaform (rarest, indurated plaques, resemble scars, behave more aggressively)
AJCC 8th edition TNM classificaiton of cutaneous squamous cell carcinoma and other cutaneous carcinomas (BCC)
T:
TX- primary tumor cannot be assessed
Tis- carcinoma in situ
T1- 2cm or less
T2- 2-4cm
T3- >4cm and/or perineural invasion or deep invasion or minor bone erosion
T4a- gross cortical bone / marrow invasion
T4b- skull base invasion
N:
NX- regional nodes cannot be assessed
N0- no regional lymph node metastases
N1- Single ipsilateral node <3cm
N2a- single ipsilateral node 3-6cm
N2b- multiple ipsilateral nodes none >6cm
N2c- bilateral or contralateral nodes, none >6cm
N3a- lymph node >6cm
N3b- Extranodal invasion
M:
MX- distant metastases cannot be assessed
M0- no distant metastases
M1- distant metastases
Primary lymphatic drainage of the oral cavity.
What are “skip metastases”?
Upper cervical lymph nodes including:
Level 1a (submental)
Level 1b (submandibular)
Level 2 (upper jugular)
Level 3 (middle jugular)
Up to 15% of TONGUE carcinomas can have “SKIP METASTASIS” to level 4 (lower jugular) without involving levels 1, 2, 3.
What is a supraomohyoid neck dissection?
Removal of lymph node levels 1, 2, 3.
Some surgeons routinely include level 4 for tongue carcinomas due to possibility of “skip metastasis”.
How are level 2 nodes divided?
Level 2a includes nodes anterior to spinal accessory nerve CN11.
Level 2b (submuscular recess above splenius capitis and levator scapulae fascia) includes nodes posterior to CN11.
Controversy regarding removal of level 2b for clinically node negative neck in oral cavity SCC due to small percentage of level 2b involvement (6%) and dreaded complication of shoulder dysfunction and pain syndrome from dissection of CN11.
Most common malignancy in oral cavity
Squamous cell carcinoma (more than 90% of oral cavity SCC).
Other malignant tumors of the oral cavity = minor salivary gland cancers, sarcomas, mucosal melanomas, lymphoma.
Most common 3 subsites of oral cancer
- lateral border of tongue
- floor of mouth
- buccal mucosa
- retromolar trigone
Risk factors oral SCC
Tobacco (initiator)
Alcohol (promoter)
Tobacco risk 5-9 fold
Alcohol risk 3-9 fold
Combined alcohol and tobacco 100 fold increase
Some studies = poor oral hygiene, chronic mechanical trauma, vitamin A, C, E deficiency, infectious agents like Candida and syphilis.
HPV association with SCC
HPV causes >80% of oropharyngeal SCC as opposed to 3-5% of oral cavity cancers.
HPV positive tumors have improved response to radiation and improved survival compared to HPV negative tumors.
Radiographic imaging used in workup for SCC
Dental radiography (50% demineralization required for radiolucency to be discernible)
CT: shows central necrosis, extracapsular spread, bony detail. Lymph nodes >1.5 cm at levels I, II and >1cm at level III are considered metastatic. Should be oval shape, if rounded more suspicious.
MRI: better for perineural invasion. Overestimates bony invasion. MRI with contrast in T1 weighted is best for tongue invasion.
PET-CT: deoxy-glucose (FDG) radiolabeled glucose molecules with radiotracer in PET scans. Any tissue with high metabolic rate lights up. Inflammation lowers specificity. Very high uptake suggestive of metastasis. Lymph nodes with standard uptake value (SUV) > 2.5 are pathological.
CXR: initial screening for distant metastasis or second primary.
Most common distant metastatic sites for SCC
lungs, liver, bones
How is oral squamous cell carcinoma classified (TNM)?
TNM
Tx: primary tumor cannot be assessed
Tis: carcinoma in situ
T1: tumor <2cm with DOI <5mm
T2: tumor <2cm with DOI 5-10mm OR tumor 2-4cm with DOI <10mm
T3: Tumor >4cm or any tumor with DOI 10-20mm
T4a: moderately advanced local disease invades adjacent structures only (cortical bone, maxillary sinus, skin of face), or extensive with bilateral tongue involvement or DOI >20mm
T4b: very advanced local disease, tumor invades masticator space, pterygoid plates, or skull base and/or encases the internal carotid artery.
Nx: regional lymph nodes cannot be assessed
N0: no regional lymph node metastasis
N1: metastasis in a single ipsilateral lymph node, <3cm
N2: a. metastasis in single ipsilateral node 3-6cm; OR b. multiple ipsilateral lymph nodes <6cm, OR c. bilateral or contralateral nodes <6cm
N3: a. metastasis in lymph node larger than 6cm or b. clinically overt extranodal extension.
M0: no distant metastasis
M1: distant metastasis
How is oral squamous cell carcinoma staged based on TNM?
Stage 0: Tis N0 M0
Stage 1: T1 N0 M0
Stage 2: T2 N0 M0
Stage 3: T3 N0 M0; T1/2/3 N1 M0
Stage 4a: T4a N0,1 M0; T1/2/3/4a N2, M0
Stage 4b: T4b any N M0
Stage 4c: Any T Any N M1
In general, early stage 1 or 2 disease defines a relatively small primary tumor (T1, T2) without any nodal involvement or distant metastasis.
Advanced stage 3 or 4 cancers include larger primary tumors (T3 or T4) with metastases to regional nodes or distant sites.
How are early stage oral SCC (Stage 1 and 2) treated?
surgery or radiation alone (survival rates comparable, but surgery preferred)
How is advanced stage oral cancer (stages 3 and 4) treated?
Surgery as initial treatment modality followed by adjuvant radiation therapy +/- chemotherapy
What are some indications for adjuvant radiation for oral SCC?
T3/T4 tumors
Positive or close <5mm margins
2 or more cervical lymph nodes containing metastatic cancer
Perineural or lymphovascular invasion
Extracapsular spread
When should adjuvant radiation be given?
within 6 weeks after surgery (poorer outcome with delayed treatment)
What are some indications for adjuvant chemotherapy?
Positive resection margins
Extracapsular spread
Improved survival outcome and locoregional control with adjuvant chemoradiation therapy with Cisplatin for these two adverse features. Chemotherapy is used to sensitize cancer cells to the effects of radiation.
Most commonly used chemotherapeutic agent for H&N cancers.
What are its side effects?
What would be used in the case of renal insufficiency?
Cisplatin. Given weekly or Q3 weeks.
Side effects include ototoxicity, nephrotoxicity, peripheral neuropathy, gastrointestinal toxicity.
Carboplatin may be used for patients with renal insufficiency.
What is an FDA approved alternative used for patients that cannot tolerate Cisplatin?
Cetuximab (monoclonal antibody targeting the endothelial growth factor receptor (EGFR).
When is a neck dissection performed for oral SCC?
- Patients with clinically negative neck with >20% chance of occult regional metastasis: Selective Neck Dissection (only nodal groups determined to be at highest risk for metastasis are removed).
- Oral tongue SCC with DOI >4mm believed to have >20% chance of regional metastasis, SND.
- Oral tongue SCC >4mm DOI within 1cm of midline, bilateral neck dissection.
SND often involves “supraomohyoid neck dissection” levels 1-3. Level 4 often included for tongue carcinomas due to skip metastasis.
Nodal positive neck (N+ neck) generally receive comprehensive neck dissection with removal of level 1-5 nodes.
How is comprehensive neck dissection classified?
Radical neck dissection (RND)
Modified radical neck dissection (MRND)
Extended neck dissection (END)
Radical neck dissection
vs.
Modified radical neck dissection
RND: Radical en bloc lymphadenectomy levels 1-5 along with SCM, IJV, CN11
MRND: same as RND, except preservation of one or more non-lymphatic structures (SCM, IJV, and/or CN11) no invaded by cancer.
- MRND type 1: CN 11 preserved
- MRND type 2: CN 11, IJV preserved
- MRND type 3: CN 11, IJV, and SCM preserved