Neoplasia Flashcards
What risk factors can predispose to development of malignant disease or transformation of benign to malignant lesion?
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?
What is the definition of dysplasia?
-Abnormal growth/maturation of cells characterised by cellular/structural atypia. Progresses starting from the basal layer
What are the degrees of dysplasia?
Mild: basal 1/3 affected
Moderate: basal 2/3 affected
Severe: Entire width of epithelium affected (also known as carcinoma in situ)
What are some features of architectural/structural atypia?
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)
What is the normal shape of rete pegs in the palate, buccal mucosa and floor of the mouth?
- Palate: finger shaped
- Buccal mucosa: finger shaped but less pronounced
- Floor of mouth: flat
What are some features of cytological dysplasia?
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)
What premalignant lesions have low risk of malignant transformation?
- Chronic candidosis
- Lichen planus
What premalignant lesions have high risk of malignant transformation?
- Speckled leukoplakia
- Dysplastic leukoplakia
- Oral submucous fibrosis
- Sublingual keratosis
What premalignant lesions have very high risk of malignant transformation?
- Erythroplakia
- Tertiary syphilis
Define leukoplakia
- Fixed White patch or plaque
- Can not be characterised clinically or pathologically as any other disease
What are the high risk sites for leukoplakia?
- Buccal mucosa (including commissure region)
- Alveolar ridges
- Retromolar area
- Anterior floor of the mouth and ventral tongue
- Tongue
What are the two main types of leukoplakia? Which has a higher proportion of dysplasia?
- Homogenous: solid white lesion
- Speckled leukoplakia: Intermingled white and red areas (Speckled has higher proportion of dysplasia)
What is the percentage of leukoplakias that transform to malignant lesion?
0.13 - 6%
What is oral submucous fibrosis? What causes it?
Betel nut chewing
- Thinning of mucosa
- Increased fibrosis in underlying CT
- Causes immobility and contraction thus limited mouth opening
Should you get a biopsy of lichen planus?
Yes, baseline biopsy in case changes occur
What is the definition of a neoplasm?
- 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
What are the two types of neoplasm? What are their characteristics?
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
What is the nomenclature system for benign tumours?
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)
What is the nomenclature system for malignant tumours?
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)
What tumours have the suffix -blastoma?
-Tumours with immature/incompletely differentiated/precurser cells (e.g. osteoblastoma)
What are some exceptions to the classic neoplasm nomeclature system?
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))
