Pathology -carcinogenesis ; Cancer Flashcards
What is carcinogenesis?
Transformation of normal to neoplastic cells through permanent mutation
What 3 things describe a neoplasm?
Autonomous, abnormal, persistent new growth
What can a neoplasm only arise from?
A nucleated cell
Can’t arise from erythrocytes but can from their precursor (erythroblasts)
What is a tumour?
Any abnormal swelling
Eg, neoplasm, inflammation, hypertrophy, hyperplasia
What do solid tumours consist of ?
Neoplastic cells and stroma
What are 2 ways tumours are classified by?
Behaviour (benign or malignant)
Histogenesis
Benign vs malignant
Invading?
Rate of growth?
Spread?
Differentiation?
Benign:
Localized (No BM invasion)
Slow growing (little mitosis figures)
Well circumcised
Exophytic (outward growth)
Encapsulated
Rare ulceration & necrosis
Close resemblance to normal tissue
Non invasive (doesn’t spread)
Malignant:
BM invading
Very fast mitosis growth (hyper dense nuclei) -stain dark
Invasive - form metastases
Endophytic - inward growth
Common necrosis & ulceration
Poorly differentiated (little resemblance to normal tissue)
How can benign structures still be pathological?
Pressure on local structures - pituitary chiasm
Obstruction
Production of hormones (prolactinoma)
Transformation —> malignant
Anxiety and stress
What is histogenesis?
Origin cell of tumour
Epithelial cells:what are they called?
Non glandular benign
Non glandular malignant
Glandular benign
Glandular malignant
Papilloma
Carcinoma
Adenoma
Adenocarcinoma
Connective tissue (sarcoma) : benign & malignant
Adipocytes
Muscle (striated)
Muscle (smooth)
Cartilage
Bone
Lipoma, liposarcoma
Rhabdomyoma, rhabdomyosarcoma
Leiomyoma, leiomyosarcoma
Chondroma, chondrosarcoma
Osteoma, osteosarcoma
Lymphoid:
What are they always?
Leukemia
Lymphoma
(Always malignant)
A basal cell carcinoma…
Never metastasize
What are:
Melanomas
Mesotheliomas
Teratoma
Melanocyte malignancy
Mesothelial malignancy-typically pleural
Cancer of all 3 embryonic germ layers
What are these 3 ?
Burkitt’s lymphoma
Kaposi sarcoma
Ewing sarcoma
B cell malignancy caused by EBV
Vascular endothelial malignancy, HIV associated
A bone malignancy
Tumours are graded based on?
Similarity to parent cell
how are the tumours graded based on similarity to parent cell?
- Well differentiated (>75% cells resemble parent)
- 10-75%
- Poorly differentiated (<10% cells resemble parent)
4 Characteristics of the neoplastic cell?
Autocrine growth stimulation - over expression of growth factor and mutation of tumour suppressor genes eg. P53 and under expression of growth inhibitors
Evasion of apoptosis
Telomerase; prevents telomeres shortening with each replication (this normally rate limits the extent of mitosis a single cell can undergo)
Sustained angiogenesis + ability to invade BM
Classes of carcinogens (cancer causing agents) & examples
Chemical - eg. Paints, dyes, rubber, soot
Viruses - EBV (burkitt’s), HPV (cervical cancer)
Ionizing + non ionizing radiation - UVB in skin cancer
Hormones, parasites, mycotoxins- eg, increased oestrogen implicated in breast cancer
MISC - eg, asbestos
Pathways of metastasis (5 steps)
- Detachment (from 1^ )
- Invasion of other tissue
- Invasion of BV
- Evasion of host defense, adherence to BV wall
- Extravasation to distant site
What are the 3 methods of spread?
Haematogenous
Lymphatic
Transcolemic
What is haematogenous spread?
Key point?
Via blood (go to bone,breast, lung, liver)
KEY POINT: 5 main metastasis to bone = BLT KP
Breast, Lung, Thyroid, Kidney, Prostate
What is lymphatic spread?
2^ formation in lymph nodes
Eg. Lymphoma (rubbery lymphadenopathy)
What is transcolemic spread?
Via exudative fluid accumulation, spread through pleural, pericardial + peritoneal effusions
