8 Disorders of Growth 1 and 2 Flashcards
Disorders of Growth 1 and 2
Objectives:
Definition of neoplasia
Classification of tumours
Characteristics of Benign vs Malignant tumours
Effects and complications of tumours
DEFINITIONS
“A NEOPLASM is an abnormal mass of tissue, the growth of which exceeds and is unco-ordinated with that of normal tissues, and which persists in the same excessive manner after cessation of the stimuli which evoked the change.”
- Sir Rupert Willis, 1960
DEFINITIONS
NEOPLASIA is the process by which a neoplasm is formed.
TUMOUR literally means swelling, but conventionally is used as a synonym for neoplasm
CLASSIFICATION OF CLASSIFICATIONS
behaviour: benign v. malignant naked eye appearance site; conformation histological what tissue does it resemble? how close is the resemblance? histogenesis: cell of origin aetiological: inheritance v. environmental functional
BEHAVIOUR
A benign tumour grows by expansion, displacing adjacent tissue
A malignant tumour grows by infiltration of local tissues, and spreads to other parts of the body
Primary tumour
original malignant tumour
Secondary tumours
“offspring” of a primary malignant tumour
SPREAD OF MALIGNANT TUMOURS
Local - direct invasion
Distant – metastasis
METASTASIS is a word used in two ways:
a secondary tumour
process by which secondary tumour is formed
ROUTES OF METASTASIS
lymphatics blood transcoelomic along epithelial-lined spaces within epithelium
ROUTES OF METASTASIS
METASTASIS VIA LYMPHATICS
tumour may directly invade lymphatics
tumour emboli filtered out, then grow, in lymph nodes
typical of epithelial malignancy
ROUTES OF METASTASIS
METASTASIS VIA BLOOD
tumour may invade blood vessels
emboli filtered out by capillary beds, eg liver, lung
typical of stromal malignancy and later stages of epithelial malignancy
ROUTES OF METASTASIS
TRANSCOELOMIC SPREAD peritoneal, pleural EPITHELIAL-LINED SPACES bronchiolo-alveolar carcinoma of lung WITHIN EPITHELIUM Paget's disease of nipple, vulva and anus
PARTICULAR SITES OF METASTASES
lymph nodes
liver: GIT carcinomas, GUS, bronchus, breast
lungs: sarcoma; carcinoma of thyroid, breast, kidney, bronchus, etc.
bone: carcinoma of breast, thyroid, bronchus, prostate, uterus
brain: carcinoma of bronchus
endocrines: carcinoma of bronchus often goes to adrenals
skin: malignant melanoma; clear cell carcinoma of kidney
TUMOUR TERMINOLOGY or NAMING NEOPLASMS
The names given to individual lesions depend upon
site
behaviour
histogenesis
BENIGN EPITHELIAL TUMOURS
Adenoma
Papilloma
Cystadenoma
Polyp - a mass attached to a surface, which may or may not be a neoplasm
MALIGNANT TUMOURS
Cancer - any malignant tumour
Carcinoma - a malignant tumour of epithelial tissue
Sarcoma - a malignant tumour of stromal tissue
MESENCHYMAL TUMOURS
are named according to the cell type, with a suffix
- oma if benign - sarcoma if malignant
e.g. lipoma and liposarcoma
THOSE ARE THE RULES
but THERE ARE ALSO EXCEPTIONS which are
deeply entrenched
sometimes silly
typically confusing
LEUKAEMIA
neoplastic proliferation of haemopoietic stem cells
neoplastic cells spill over into the blood stream
all regarded as
malignant
LYMPHOMA
malignant proliferation of cells of lymphoid tissue
Two types
Hodgkin’s disease
mixture of cells, including Reed-Sternberg cells
non-Hodgkin’s lymphoma
lacks the cellular mixture of Hodgkin’s disease
TERATOMA
arises from “totipotential” cells, producing tissues representing all three germ cell layers
ovary (usually benign)
testes (usually malignant)
midline (sequestered primitive cells)
PRECURSORS OF MALIGNANCY
PREMALIGNANT CONDITIONS
lesions with an increased risk of the development of invasive tumour
can be non-neoplastic or neoplastic
PREMALIGNANT CONDITIONS - EXAMPLES
NON-NEOPLASTIC chronic inflammation varicose leg ulcers can lead to skin cancer cirrhosis of the liver hepatocellular carcinoma chronic ulcerative colitis adenocarcinoma of the large intestine xeroderma pigmentosum squamous cell carcinoma of the skin
PREMALIGNANT CONDITIONS - EXAMPLES
NEOPLASTIC familial polyposis coli autosomal dominant 1000s of large intestinal adenomas carcinoma inevitable intra-epithelial neoplasia: nuclear changes of carcinoma, without breaching basement membrane - "dysplasia" or "carcinoma-in-situ" - important in uterine cervix, vulva, bronchus, etc.
PREMALIGNANT CONDITIONS - EXAMPLES
Cervical intra-epithelial neoplasia
- Normal
- CIN i
- CIN ii
- CIN iii
TUMOUR STAGING AND GRADING
Grading
how bad it looks
Staging
how far its got
TUMOUR GRADING
an assessment of the degree of differentiation of a tumour
correlates with how aggressive the tumour behaves
only relevant for malignant tumours
usually define 3 or 4 grades
PROBLEMS WITH TUMOUR GRADING
very subjective
poor reproducibility
appearances vary from area to area within most tumours
need different criteria for each histogenesis
only modest predictor of outcome
TUMOUR STAGING
based on three main features size of primary tumour extent of lymph node disease any blood-borne metastasis sometimes quoted as "TNM"
TUMOUR STAGING
The TNM system
T = size of tumour (T1 to T4)
N = extent of lymph node involvement (N0 to N3)
M = distant metastasis (M0 to M1)
criteria different for each tumour
better prediction of outcome than grade, for most tumours
THE EFFECTS OF TUMOURS
displacement or destruction of normal structures
excess “normal” function
paraneoplastic phenomena
EFFECTS OF BENIGN TUMOURS
EXAMPLES Mechanical pressure meningioma compressing brain ovarian cystadenoma compressing ureter Obstruction atrial myxoma leiomyoma in GIT Ulceration mucosa over gastric leiomyoma
EFFECTS OF BENIGN TUMOURS
Meningioma compressing brain MORE EXAMPLES Infarction of pedunculated tumour subserosal leiomyoma of uterus Infection bladder papilloma Rupture of cystic neoplasm mucinous cystadenoma of appendix causing pseudomyxoma peritonei Hormone production islet cell tumour of pancreas Malignant change Rupture of mucinous cystadenoma of appendix causing pseudomyxoma peritonei
EFFECTS OF MALIGNANT TUMOURS
EXAMPLES
All the physical effects of benign tumours
Tissue destruction
cancer of the cervix infiltrating ureter
cancer of the stomach infiltrating pancreas
Haemorrhage
any cancer breaching a vessel wall
EFFECTS OF MALIGNANT TUMOURS
MORE EXAMPLES Secondary infection bacterial invasion of necrotic tumour Cachexia severe weight loss increased metabolic rate tissue necrosis factor, etc
EFFECTS OF MALIGNANT TUMOURS
MORE EXAMPLES Pain Anaemia haemorrhage bone marrow replacement haemolysis Paraneoplastic syndromes
PARANEOPLASTIC SYNDROMES
Ectopic hormone production
carcinoma of bronchus may cause Cushing’s syndrome, inappropriate ADH secretion, secretion of PTH analogue
fibrosarcoma can produce hypoglycaemia
renal carcinoma can release erythropoetin
PARANEOPLASTIC SYNDROMES
Peripheral neuropathy, cerebellar degeneration, myopathy
Thrombophlebitis migrans
carcinoma of bronchus (5%) and pancreas (30%)
Acanthosis nigricans
caused by epidermal growth factor analogue
PARANEOPLASTIC SYNDROMES
Nephrotic syndrome
proteinuria, hypoalbuminaemia, generalised oedema
complexes of tumour antigen and host antibody deposited in glomerulus
Finger clubbing
Hypertrophic pulmonary osteoarthropathy
Non-bacterial thrombotic endocarditis
