Benign And Malignant Tumours Flashcards
Definition of a tumour
Any abnormal swelling e.g. neoplasm, inflammation, hypertrophy, hyperplasia
All neoplasm are tumours but not all tumours are neoplasms
Definition of a neoplasm
A lesion resulting from the AUTONOMOUS or relatively autonomous ABNORMAL growth of cells which PERSISTS after the initiating stimulus has been removed
A new and abnormal growth of tissue in a part of the body, especially as a characteristic of cancer
Summary of neoplasms
Autonomous, abnormal persist at new growths
Common
High mortality
Benign -> malignant
Tumour cells and stroma
Angiogenesis essential to growth
Behavioural classification of neoplasms
Benign
Borderline
Malignant
Behavioural characteristics of benign neoplasms
E.g. Tubulovillous adenoma
Localised (no BM invasion)
Slow growing
Well circumscribed
EXOPHYTIC (outward growth)
Rare ulceration + necrosis
Close resemblance to normal tissue
They can cause morbidity and mortality
- pressure on adjacent structures
- obstruct flow
- production of hormones
- transformation to malignant neoplasm
- anxiety
Behavioural characteristics of malignant neoplasms
E.g prostate cancers, squamous cell carcinoma
BM invading
V.fast mitotic growth - HYPERDENSE NUCLEI
Poor circumscription
ENDOPHYTIC - inward growing
Common necrosis + ulceration
Poorly differentiated
Can cause morbidity or mortality
- destruction of adjacent tissue
- pressure on structures
- metastasis
- blood loss from ulcers
- obstruction of flow
- hormone production
- paraneoplastic effects (SIADH, Cushings)
- anxiety and pain
Where may neoplasia arise from + general naming rule?
Epithelial cells
- non glandular benign = PAPILLOMA
- non glandular malignant = CARCINOMA
- glandular benign = ADENOMA
- glandular malignant = ADENOCARCINOMA
Connective tissue
- SARCOMA
Lymphoid/haematopoietic organs
- leukemia, lymphoma (always malignant)
= All neoplasm have the suffix ‘oma’
= prefix depending on behavioural classification and cell type
Benign epithelial neoplasm nomenclature
Prefix with cell type of origin
- papilloma + cell type of origin = squamous cell papilloma
- adenoma + cell type or origin = thyroid adenoma
Papilloma definition
Benign tumour of non-glandular, non-secretory epithelium
Adenoma defintion
Benign tumour of glandular or secretory epithelium
Malignant epithelium neoplasm nomenclature
Carcinoma + epithelial cell type = transitional cell carcinoma
Carcinomas of glandular epithelium = adenocarcinoma
Carcinoma defintion
Malignant tumour of epithelial cells
Benign connective tissue neoplasms nomenclature
- adipocytes
- cartilage
- bone
- vascular
- muscle, smooth
- muscle, striated
Named according to cell of origin -suffix by ‘oma’
Lipoma - adipocytes
Chondroma - cartilage
Osteomalacia - bone
Angioma - vascular
Leiomyoma - muscle, smooth
Rhabdomyoma - muscle, striated
Malignant connective tissue neoplasms
- adipose tissue
- striated muscles
- smooth muscles
- bone cartilage
- bone
- blood vessels
Sarcoma prefixed by cell type of origin
Liposarcoma - adipose tissue
Rhabdomyoscarcoma - striated muscles
Leiomyosarcoma - smooth muscles
Chondrosarcoma - bone cartilage
Osteosarcoma - bone
Angiosarcoma - blood vessels
How are carcinomas and sarcomas classified?
According to degree of differentiation - the less differentiated they are the higher the grade
Exceptions to the rule: not all ‘-omas’ are neoplasms
Granuloma,
Tuberculoma
Exceptions of the rule: Not all malignant tumours are carcinoma or sarcoma
Melanoma - malignant neoplasms of melanocytes
Mesothelioma - malignant tumour of mesothelial cells
Lymphoma - malignant neoplasm of lymphoid cells
Exceptions of the rule: eponymously named tumours
Burkitt’s lymphoma - B cell malignancy caused by EBV
Ewing’s sarcoma - bone malignancy
Grawitz tumour
Kaposi’s sarcoma - vascular endothelial malignancy HIV associated
Exclusion of neoplasm: teratoma
Neoplasm containing tissues from all 3 embryological layers
Tumours graded based on similarity to parent cell
Well differentiated (>75% cells resemble parent)
10-75%
Poorly differentiated (<10% cells resemble parent)
Characteristics of the neoplastic cell
Autocrine growth stimulation = over expression of GF and mutation of tumour suppressor genes e.g 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 carcinogenesis (cancer-causing agents)
Chemical - e.g. paints, dyes, rubber, soot
Viruses - EBV (Burkitts), HPV (cervical cancer)
Ionising + Non ionising radiation - UVB in skin cancer, ionising is lots
Hormones, parasites, mycotoxins - e.g. increased oestrogen implicated in breast cancer
Misc e.g Asbestos
Germ line vs somatic mutations
Germ line = mutated ORIGINAL GERM CELL = will pass onto next gen
Somatic = mutated MITOTIC COPY OF GERM CELL = wont pass to next gen
Pathway of metastasis
- Detachment (from 1’)
- Invasion of other tissues
- Invasion of BV
- Evasion of host defence, ADHERENCE of BV wall
- Extravasation to distant site
Methods of spread
HAEMATOGENOUS = via blood = bone, breast, lung, liver
- 5 main mets to bone = BLT KP = breast, lung, thyroid, kidney, prostate
LYMPHATIC = 2’ formation in lymph nodes e.g. lymphoma (rubbery lymphadenopathy)
TRANSCOLEMIC = via Exudative fluid accumulation, spreads through PLEURAL, PERICARDIAL + PERITONEAL EFFUSIONS
Sarcomas spread mostly
Haematogenous
Carcinomas spread mostly
Lymphatic
* exceptions =
- follicular thyroid
- chondrocarcinoma
- RCC
- HCC
Staging Tumours
Mostly TNM (Tumour - Node - Metastasis)
Different for leukemias + lymphomas and CNS cancers
E.g lymphoma = Ann Arbour
Mutation involved in colorectal cancer
FAP (familial adenomatous polyposis) = Autosomal dominant mutation APC gene, millions of colorectal adenomas
- inevitable adenocarcinoma by 35 years old
- over expression of c-MYC and point mutation in KRAS
HNPCC (lynch syndrome) = mutated MSH gene, autosomal dominant, this genes involved in DNA mismatch repair
Screening
Method of early detection (essentially 2’ prevention, making management easy)
Cancers screened for in UK = CERVICAL (cervical swab), BREAST (mammograms), COLORECTAL (faecal occult)
Heel prick test birth = sickle cell, CF, hypothyroid
