Characteristics of Tumours (18) Flashcards
Cancer
Uncontrolled growth of cells, can invade and spread to distance sites of body
Tumour/neoplasm
Lesion resulting from autonomous growth/abnormal growth of cells that persists in the absence of the initiating stimulus/abnormal swelling
Histogenesis
Differentiation of cells into specialised tissues and organs during growth from undifferentiated cells (3 primary germ layer)
Carcinoma
Epithelial cells
Sarcoma
Connective tissues
Lymphoma/leukaemia
Lymphoid/haematopoietic organs
Common and fatal cancers
Lung, breast/prostate, colon and rectum
Characterising tumours (DRLM)
Differentiation, rate of growth, local invasion, metastasis
Differentation
The extent that neoplastic cells resemble the normal parenchymal cells (morphologically and functionally)
Benign tumours and differentation
Well-differentiated, mitoses are rare
Anaplasia
Neoplasms comprised of poor-differentiated cells (malignant)
Differentiation - morphological changes
- Pleomorphism
- Abnormal nuclear morphology
- Mitoses
- Loss of polarity
Abnormal nuclear morphology
Too large (nuclear:cytoplasmic 1:1), irregular shape, chromatin distribution (coarsely clumped, along cell membrane), hyper chromatism (dark colour) abnormally large nucleoli
Differentiation - mitoses
Atypical, bizarre mitotic figure - tripolar, quadripolar, multipolar spindles
Differentiation - loss of polarity
Orientation of cells disturbed, disorganised growth
Well differentiated grade
Low grade/grade 1
Moderately differentiated grade
Intermediate/grade 2
Poorly differentiated grade
High grade/grade 3
Stage
A measure of prognostication/therapeutic decisions
Bronchogenic carcinoma secretes
Corticotropin, parathyroid-like hormone, insulin, glucagon
Local invasion - cancer
Infiltration, invasion, destruction
Local invasion - benign
Cohesive expansile masses, localised to origin of site, no capacity to infiltrate/invade/metastasise
Benign tumours - encapsulation
Rim of fibrous tissue, ECM deposited by stromal cells activated by hypoxia from pressure of tumour, tissue plane - discrete, moveable, easily palpable, easily excised
Metastasis
Spread of tumour to sites physically discontinuous with primary tumour
Pathways of metastasis
Direct seeding, lymphatic (most common), haematogenous (veins more easily penetrated)
Sentinel nodes
First node in a regional lymphatic bin that receives lymph flow from primary tumour, frozen during surgery can guide surgeon to appropriate therapy
How are sentinel nodes identified?
Injection of radio labelled tracers/coloured dyes
Regional nodes
Effective barriers to further tumour dissemination, drainage of tumour cell debris and antigens induces reactive changes in nodes
Stroma
Connective tissue framework that neoplastic cells are embedded in
What does a stroma provide?
Mechanical support, intercellular signalling, nutrition
Desmoplastic reaction
Fibrous stroma formation due to induction of connective tissue fibroblast proliferation by growth factors from tumour cells
Stroma contains
Cancer-associated fibroblasts, myofibroblasts, blood vessels, lymphocytic infiltrate
Clinical complications of tumours - compression
Displacement of adjacent tissues, benign
Clinical complications of tumours - destruction
Invasion, rapidly fatal if vital structures invaded, mucosal surfaces (ulceration)
Clinical complications of tumours - metabolic
Paraneoplastic (ACTH/ADH in small cell lung cancer), cachexia (interfere protein metabolism), Warburg effect (energy by high rate glycolysis with fermentation of lactic acid), neuropathies, myopathies, venous thrombosis
