Pathology of the GI Tract- Oral cavity and salivary glands (part 3 of 4)

Question 1

what is the odontogenic tumor we discussed?

Answer 1

keratocystic odontogenic tumor

Question 2

the keratocystic odontogenic tumors are most commonly seen in what age group?

Answer 2

most often diagnosed in patients between 10 and 40

Question 3

95% of head and neck cancers are what type?

Answer 3

squamous cell carcinomas (SCCs)

Question 4

what is the etiology of SCC in the head/neck?

Answer 4

it is multifactorial–> 1) HPV 2) tobacco and alcohol 3) Betel quid and Paan (india/asia) 4) actinic radiation and pipe smoking

Question 5

what is now the leading cause of SCC in the head/neck?

Answer 5

HPV

Question 6

what variants of HPV are associated with OPSCC?

Answer 6

HPV 16 and 18

Question 7

what is at the most risk for HPV related cancers of the head and neck?

Answer 7

white, non-smoking males age 35-55

Question 8

in the head and neck, HPV demonstrates tropism for what?

Answer 8

lymphoid-associated structure of the oropharynx, including the palatine and lingual tonsils

Question 9

what does infection of the tonsillar epithelium with HPV result in?

Answer 9

aberrant basal cell differentiation, dysplasia, carcinoma in situ, and finally invasive carcinoma

Question 10

the oncogenic potential of HPV can largely be explained by the activity of what?

Answer 10

two viral genes encoding E6 and E7

Question 11

what does HPV E7 inhibit/block?

Answer 11

p21 and RB pathways

Question 12

what does HPV E6 inactivate/inhibit?

Answer 12

p53

Question 13

what happens to the HPV genome and what does this suggest?

Answer 13

the HPV genome is integrated into the host genome, suggesting that integration of viral DNA is important for malignant transformation

Question 14

how do patients with HPV-positive SCC compare to patients with HPV-negative tumors?

Answer 14

patients with HPV-positive SCC have greater long-term survival than those with HPV negative tumors

Question 15

what are the clinical presentations associated with OPSCC?

Answer 15

non specific symptoms such as sore throat, ear ache, pain on swallowing, and weight loss; can present as a metastatic tumor in the lymph node

Question 16

how can you identify if the OPSCC is caused by HPV?

Answer 16

if there is overexpression of p16 (a cell cycle inhibitor); or if the brown staining is positive

Question 17

what is the second most common cause of classic oral SCC?

Answer 17

smoking/ tobacco

Question 18

the development of classic oral SCC is driven by what?

Answer 18

the accumulation of mutations and epigenetic changes that alter the expression and function of oncogenes and tumor suppressor genes

Question 19

several genes have been proposed as playing critical roles in SCC- what are they?

Answer 19

TP53, CDKN2A, and PIK3CA

Question 20

a number of novel and potentially targetable genetic alterations have been identified in cases of SCC, what are they?

Answer 20

NOTCH1 and FAT1

Question 21

what is the most frequently mutated gene in cases of SCC?

Answer 21

TP53

Question 22

where are the common locations for oral SCC to present?

Answer 22

ventral tongue, floor of mouth, lower lip, soft palate, gingiva (look under dentures)

Question 23

what are the classic SCCs typically preceded by?

Answer 23

the presence of premalignant lesions

Question 24

what are two examples of premalignant lesions associated with classic oral SCC?

Answer 24

erythroplakia and leukoplakia

Question 25

how is leukoplakia defined?

Answer 25

a white patch or plaque that cannot be scraped off and cannot be characterized clinically or pathologically as any other disease

Question 26

what % of leukoplakias end up to be precancerous?

Answer 26

25%

Question 27

how is erythroplakia defined?

Answer 27

a red, velvety, possibly eroded area within the oral cavity that usually remains level with or may be slightly depressed in relation to the surrounding mucosa

Question 28

which is worse, leukoplakia or erythroplakia?

Answer 28

erythroplakia- this premalignant lesions is almost always associated with severe dysplasia/ carcinoma in situ

Question 29

what are the characteristics of dysplasia?

Answer 29

pleomorphism, increased mitotic figures, loss of architectural orientation, and loss in cell uniformity

Question 30

what two histologic terms should point you directly towards SCC?

Answer 30

keratin pearls and intercellular bridges

Question 31

what is a marker for SCC?

Answer 31

p63 and cyclin D1

Question 32

what is the theory of field cancerization?

Answer 32

multiple independent primary tumors develop as the result of years of chronic exposure of the mucosa to carcinogens

Question 33

how do first primary tumors compare to second primary tumors?

Answer 33

first primary tumors have a much higher survival rate, whereas second primary tumors are the most common cause of death