Neoplasia Flashcards
What is neoplasia?
A lesion resulting from autonomous or relatively autonomous abnormal growth of cells which persists after initialising stimulus removed
What makes a neoplasm malignant?
The ability to invade and metastasise. Potentially lethal with abnormal characteristics
What is a benign neoplasm?
A neoplasm that does not have the ability to invade and metastasise
4 main distinguishing features of neoplasms
Differentiation, rate of growth, local invasion, metastasis
What is differentiation in relation to neoplasms?
The extent to which neoplastic tissues resemble their tissue of origin.
Features of well differentiated neoplasms?
Looks close to tissue of origin, little or no anaplasia, can be malignant but more frequently benign
Features of poorly differentiated neoplasms?
Little resemblance to tissue of origin. Nuclear pleomorphism; abnormal nuclear features e.g. high nuclear:cytoplasm ratio, clumped chromatin, prominent nucleoli; increased mitotic activity; tumour giant cells; necrosis
Features of undifferentiated/anaplastic neoplasms?
Cannot be identified by morphology alone, may need special stains/techniques to diagnose
What is the difference between grade and stage of neoplasms?
Grade = how differentiated the tumour is (1= well differentiated, 3 = poor)
Stage = extent of spread of tumour (lower the better)
What is dysplasia?
Confined neoplastic change - features of malignancy but confined within basement membrane
What is carcinoma in situ?
Dysplastic changes that cover the full thickness of epithelium but without invasion - basement membrane not penetrated
Why are mitosis and necrosis associated with tumour rate of growth?
Malignant neoplasms are fast growing, benign are slow growing. Mitosis is a sign that lots of cells are dividing rapidly while necrosis is a sign that the tumour is growing so fast the blood supply can’t keep up
Local invasion - benign tumours
Cohesive and expansile masses, localised, don’t metastasise, usually slow growing and may be encapsulated
Local invasion - malignant tumours
Invasive, penetrate organ walls, tissues, epithelial surfaces, most reliable way of distinguishing malignant tumour next to metastases
Benign tumour of glandular/secretory epithelium
Adenoma (prefix with name of glandular tissue of origin e.g. colonic adenoma)
Naming of benign tumours
Suffix -oma
Benign tumour of non-glandular/surface epithelium
Papilloma (prefix with cell type of origin e.g. squamous cell papilloma)
Naming of benign mesenchymal tumours
Suffix -oma (preceded by tissue or cell of origin e.g. osteoma for benign tumour of bone, leiomyoma for benign tumour of smooth muscle)
Naming of malignant epithelial tumours
Carcinoma
If from glandular epithelium, called adenocarcinoma
If from non-glandular epithelium, carcinoma prefixed with cell of origin e.g. squamous cell carcinoma
Malignant tumour of glandular epithelium
(Epithelium source) adenocarcinoma e.g. colonic adenocarcinoma, breast adenocarcinoma
Malignant tumour of non-glandular surface epithelium
(Cell type) carcinoma e.g. Basal cell carcinoma, squamous cell carcinoma
Naming of malignant mesenchymal tumours
Sarcoma prefixed with tissue or cell of origin e.g. rhabdomyosarcoma (malignant skeletal muscle tumour) or angiosarcoma (malignant blood vessel tumour)
What is a teratoma?
Tumour of germ cell origin containing cells representing all three germ layers. Can be benign or malignant
What is a precursor cell tumour?
Tumour with histological resemblance to embryological tissue in which they arise e.g. retinoblastoma, hepatoblastoma. Often occur in young patients
