8 Disorders of Growth 1 and 2 Flashcards by Michele Herbert

Disorders of Growth 1 and 2

Objectives:

Definition of neoplasia

Classification of tumours

Characteristics of Benign vs Malignant tumours

Effects and complications of tumours

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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

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DEFINITIONS

NEOPLASIA is the process by which a neoplasm is formed.

TUMOUR literally means swelling, but conventionally is used as a synonym for neoplasm

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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

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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

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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

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ROUTES OF METASTASIS

lymphatics
  blood
  transcoelomic
  along epithelial-lined spaces
  within epithelium

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ROUTES OF METASTASIS

METASTASIS VIA LYMPHATICS
tumour may directly invade lymphatics
tumour emboli filtered out, then grow, in lymph nodes
typical of epithelial malignancy

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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

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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

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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

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TUMOUR TERMINOLOGY or NAMING NEOPLASMS

The names given to individual lesions depend upon
site
behaviour
histogenesis

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BENIGN EPITHELIAL TUMOURS

Adenoma
Papilloma
Cystadenoma

Polyp - a mass attached to a surface, which may or may not be a neoplasm

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MALIGNANT TUMOURS

Cancer - any malignant tumour

Carcinoma - a malignant tumour of epithelial tissue

Sarcoma - a malignant tumour of stromal tissue

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MESENCHYMAL TUMOURS

are named according to the cell type, with a suffix

- oma    		if benign
	- sarcoma		if malignant

e.g. lipoma and liposarcoma

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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