Neoplasia

Question 1

What risk factors can predispose to development of malignant disease or transformation of benign to malignant lesion?

Answer 1

History:

• UV exposure
• Tobacco use
• Alcohol intake

Clinical features:

• Age
• Gender

Specific to transformation:

• Type of lesion
• Location (if at high risk site e.g. at site where patient chews beetle nut)
• Degree of dysplasia?

Question 2

What is the definition of dysplasia?

Answer 2

-Abnormal growth/maturation of cells characterised by cellular/structural atypia. Progresses starting from the basal layer

Question 3

What are the degrees of dysplasia?

Answer 3

Mild: basal 1/3 affected
Moderate: basal 2/3 affected
Severe: Entire width of epithelium affected (also known as carcinoma in situ)

Question 4

What are some features of architectural/structural atypia?

Answer 4

Overall arrangement

• Drop shaped rete pegs
• Irregular stratification

Mitosis

• Increased number of mitotic figures
• Suprabasal mitosis

“Macro” cell changes:

• Loss of polarity of basal cells
• Single cell keratinisation (dyskeratosis)

Question 5

What is the normal shape of rete pegs in the palate, buccal mucosa and floor of the mouth?

Answer 5

• Palate: finger shaped
• Buccal mucosa: finger shaped but less pronounced
• Floor of mouth: flat

Question 6

What are some features of cytological dysplasia?

Answer 6

Pleomorphism (abnormal size/shape of:)

• Nucleus
• Cell
• Nuclear size generally increased

Nucleus

• Increased nuclear: cytoplasm ratio
• Increased number + size of nucleoli
• Hyperchromasia (increased staining due to more nuclear material)

-Atypical mitotic figures (cells may try to divide into 3 or 4 rather than 2)

Question 7

What premalignant lesions have low risk of malignant transformation?

Answer 7

• Chronic candidosis

- Lichen planus

Question 8

What premalignant lesions have high risk of malignant transformation?

Answer 8

• Speckled leukoplakia
• Dysplastic leukoplakia
• Oral submucous fibrosis
• Sublingual keratosis

Question 9

What premalignant lesions have very high risk of malignant transformation?

Answer 9

• Erythroplakia

- Tertiary syphilis

Question 10

Define leukoplakia

Answer 10

• Fixed White patch or plaque

- Can not be characterised clinically or pathologically as any other disease

Question 11

What are the high risk sites for leukoplakia?

Answer 11

• Buccal mucosa (including commissure region)
• Alveolar ridges
• Retromolar area
• Anterior floor of the mouth and ventral tongue
• Tongue

Question 12

What are the two main types of leukoplakia? Which has a higher proportion of dysplasia?

Answer 12

• Homogenous: solid white lesion

- Speckled leukoplakia: Intermingled white and red areas (Speckled has higher proportion of dysplasia)

Question 13

What is the percentage of leukoplakias that transform to malignant lesion?

Answer 13

0.13 - 6%

Question 14

What is oral submucous fibrosis? What causes it?

Answer 14

Betel nut chewing

• Thinning of mucosa
• Increased fibrosis in underlying CT
• Causes immobility and contraction thus limited mouth opening

Question 15

Should you get a biopsy of lichen planus?

Answer 15

Yes, baseline biopsy in case changes occur

Question 16

What is the definition of a neoplasm?

Answer 16

• Abnormal mass of tissue
• Growth exceeds and is uncoordinated with normal tissues
• Persists after removal of stimulus that evoked the chagne
• Growth is autonomous and irreversible
• Tumour refers to the swelling

Question 17

What are the two types of neoplasm? What are their characteristics?

Answer 17

Benign

• Grow slowly
• Remain localised
• Smooth, homogenous, uniform in colour
• Cells similar to tissues of origin

Malignant

• Grow rapidly
• Spread to distant sites
• Irregular, not homegnous, variable in colour
• Cells variably resemble tissue of origin, many mitoses, dysplastic features

Question 18

What is the nomenclature system for benign tumours?

Answer 18

Epithelial origin

• Surface epithelium: Add papilloma on the end (e.g. squamous cell papilloma, intraductal papilloma)
• Glandular epithelium: Add adenoma on the end (e.g. thyroid adenoma)

Connective tissue/endocrine origin:
-Suffix -oma (e.g. fibroma, osteoma, lipoma)

Question 19

What is the nomenclature system for malignant tumours?

Answer 19

Epithelial origin:

• Surface epithelium: add carcinoma on the end (e.g. squamous cell carcinoma)
• Glandular epithelium: add adenocarcinoma at the start (e.g. adenocarcinoma of thyroid)

Connective tissue origin/endocrine:
-Suffix -sarcoma (e.g. fibrosarcoma, osteosarcoma, liposarcoma, chondrosarcoma, osteochondrosarcoma)

Question 20

What tumours have the suffix -blastoma?

Answer 20

-Tumours with immature/incompletely differentiated/precurser cells (e.g. osteoblastoma)

Question 21

What are some exceptions to the classic neoplasm nomeclature system?

Answer 21

Some -oma’s are malignant

• Melanoma
• Lymphoma
• Glioma

Some -oma’s describe non-neoplastic developmental overgrowths

• Hamartoma: excess amount of normal tissue in normal situation (e.g. lymphangioma, haemangioma “birthmarks”
• Choristoma: Excess of tissue in abnormal situation (pancreatic tissue in duodenum)

Sometimes -oma is used to describe collection of blood or granulation tissue

Some malignancies have other names (leukemia (leukocytes), myeloma (plasma cells))