benign and malignant tumours Flashcards
what is a tumour
any abnormal swelling
4 types of tumour
neoplasm
inflammation
hypertrophy
hyperplasia
define neoplasm
a lesion resulting from the autonomous or relatively autonomous abnormal growth of cells which persists after the initiating stimulus has been removed
4 features of a neoplasia
- autonomous
- abnormal
- persistent
- new growth
summary of neoplasms
Autonomous, abnormal, persistent new growths
Common
High mortality
Benign -> malignant
Tumours cells and stroma
Angiogenesis essential to growth
why study neoplasia
25% of population develop a neoplasm - not all malignant
all ages can suffer
risk increases with age
high mortality rate
account for 20% of all deaths
what is the most common cause of cancer death in males
LUNG
then prostate
then bowel
what neoplasms are usually borderline malignant
found in ovaries
either look benign but behave in a malignant way
or look malignant but behave in a benign way
most common cause of cancer death in females
LUNG
then breast
then bowel
what are the 2 components of a neoplasm structure
neoplastic cells
surrounding stroma
describe strutcure of neoplastic cells
derive from nucleated cells
usually monoclonal
growth pattern & synthetic activity related to parent cell (eg if from thyroid, will grow like thyroid, may even produce same hormone)
describe structure of stroma of neoplasm
made of connective tissue framework
gives mechanical support & nutrition
describe tumour angiogenesis
- trans formed cell
- a vascular tumour nodule
- vascularised tumour
- vascularised tumour with central necrosis
this is growth of tumour
describe angiogenesis in benign vs malignant
benign - neoplasm growth tends to keep up with blood supply
malignant - neoplasms grow faster and may grow faster than blood supply so middle of the tumour dies - central necrosis
why do we classsify neoplasms
to determine appropriate treatment
to provide prognostic info
to aid communication
what are the 2 ways to classify neoplasms
behavioural - benign/malignant
histogenetic - cell of origin
what are the 3 behavioural classifications of neoplasms
benign
borderline
malignant
describe benign neoplasms
- localised, non invasive
- slow growth rate
- low mitotic activity
- close resemblance to normal tissue
- circumscribed or encapsulated
2 examples of benign neoplasms
Fibroid
Tubulovillous adenoma
describe histology of benign neoplasm
nuclear morphometry often normal
necrosis rare
ulceration rare
growth on mucosal surfaces usually exophytic - up and outwards
why should we worry about benign neoplasms
they can still cause morbidity and mortality
through diff ways:
1. pressure on adjacent structures
2. obstruct flow
3. produce hormones
4. transform to malignant neoplasm
5. anxiety
describe malignant neoplasms
- invasive (defining feature)
- metastases (not all metastasise)
- rapid growth rate
- variable resemblance to normal tissue
- poorly defined or irregular border
describe histology of malignant neoplasms
Hyperchromatic nuclei - darker than normal
Pleomorphic nuclei - larger than normal
Increased mitotic activity
Necrosis and ulceration common
Growth on mucosal surfaces and skin
often endophytic
examples of malignant neoplasms
Prostate cancer
Squamous cell carcinoma
why worry about malignant neoplasms
cause morbidity and mortality
because of:
1. destruction of adjacent tissue
2. metastases
3. blood loss from ulcers
4. obstruct flow
5. produce hormones
6. paraneoplastic effects
7. anxiety and pain
define histogenesis
the specific cell of origin of a neoplasm
histopathologist examination required
specifies neoplasm type
what can neoplasms arise from (3)
epithelial cells
connective tissue
lymphoid/haematopoetic organs
nomenclature of neoplasms
Suffix: ‘-oma’
Prefix: depends on behavioural classification and cell type
what is a papilloma
a benign neoplasm of non-glandular non secretory epithelium
prefix with cell type of origin eg squamos cell papilloma
what is an adenoma
a benign neoplasm of glandular or secretory epithelium
prefix with cell type of origin eg thyroid adenoma, colonic adenoma
definition of carcinoma
malignant epithelial neoplasm
what are adenocarcinomas
all carcinomas of glandular epithelium
how are benign connective tissue neoplasms named
according to cell type of origin, suffixed by ‘oma’
lipoma - adipocutes
chondroma - cartilage
osteoma- bone
angloma- vascular
rhabdomyoma - striated muscle
leiomyoma - smooth muscle (common)
neuroma - nerves
how are malignant connective tissue neoplasms named
Sarcoma’ prefixed by cell type of origin:
Liposarcoma: adipose tissue
Rhabdomyosarcoma: striated muscle
Leiomyosarcoma: smooth muscle
Chrondrosarcoma: cartilage
Osteosarcoma: bone
Angiosarcoma: blood vessels
how are malignant neoplasms carcinomas and sarcomas further classified
by how closely they resemble normal tissue (degree of differentiation)
what is an anaplastic neoplasm
where the cell type of origin cannot be determined
exceptions to nomenclature rules
Not all ‘-omas’ are neoplasms
* e.g. granuloma, mycetoma, tuberculoma
Not all malignant neoplasms are carcinomas or sarcomas, e.g.:
* Melanoma: malignant neoplasm of melanocytes
* Mesothelioma: malignant neoplasm of mesothelial cells
* Lymphoma: malignant neoplasm of lymphoid cells
Embryonal tumours
Mixed tumours
APUDomas
Carcinosarcomas
what are Eponymously named neoplasms (exceptions)
- Burkitt lymphoma
• Ewing sarcoma
• Grawitz tumour
• Kaposi sarcoma
what are blastomas
neoplasms that represent embryonic toissue
what are teratomas
neoplasms containing tissues from all 3 embryological layers
these are also an exception to nomenclature rules
what are all sarcomas
malignancies of connective tissue
