Path - Anatomy - Exam 3 Flashcards
Define agenesis
The complete absence of an organ or part of an organ
Define aplasia:
The almost complete lack of development of an organ, or part of an organ The clue is the presence of an anlarge (a rudiment that indicates where the organ is supposed to be).
Sometimes the word is used to indicate that there is a lack of any multiplying cells in an organ, i.e. aplastic anemia.
Define hypoplasia:
The lack of development of an organ to a full or mature size.
Define atrophy:
The acquired reduction in the size of an organ after its mature dimensions have been obtained
Applies to both a reduction in number and/or in size of component cells.
Define hypertrophy:
Reversible enlargement of an organ due to an increase in the size of component cells
Define Hyperplasia:
Reversible enlargement of an organ due to increase in the number of specialized cells
What are some of the causes of generalized atrophy?
- inadequate nutrition
- old age
- disseminated malignancy
- chronic infection
- radiation/chemotherapy using antimetabolites
- disuse – i.e. prolonged bed rest
What are some of the causes of localized atrophy?
- ischemia
- pressure
- disuse (decreased work load)
- hormonal
- immunological, i.e. pernicious anemia
- toxic and metabolic conditions
Discuss these quantitative growth abnormalities (atrophy, hypertrophy, hyperplasia) and their causes.
- atrophy
- hypertrophy
- hyperplasia
Causes:
a) Atrophy: G1
Reduced RNA and protein synthesis in G1 results in failure to grow and replicate (atrophy)
b) Hypertrophy:
i) Inhibition of DNA synthesis only, results in cell enlargement without cell division
ii) Block in mitosis results in cell enlargement without division
c) Hyperplasia: G0
Block in pathway to G0 will result in cells continuing in cell cycle to produce increased cell numbers
What could cause agenesis, aplasia or hypoplasia?
a) Hereditary – pygmies
b) environmental
c) physical, i.e. trauma, tradiation
d) chemical – thalidomide, alcohol etc
e) Microbiological, rubella, CMV, other herpes, parvo B19 etc
What are the four mechanisms of atrophy?
- Decreased anabolism
- Increased catabolism
- Reduced cell replication
- Increased apoptosis
Describe how hypertrophy and hyperplasia arise in relation to the normal cell cycle and give examples in physiological and pathological circumstances.
a) Hypertrophy:
i) Inhibition of DNA synthesis only, results in cell enlargement without cell division
ii) Block in mitosis results in cell enlargement without division
b) Hyperplasia: G0
Block in pathway to G0 will result in cells continuing in cell cycle to produce increased cell numbers
Physiological circumstances:
- female breast at puberty, pregnancy and lactation – hypertrophy and hyperplasia
- Bone marrow hyperplasia – anemia
- Lymphoid hyperplasia – infections
- Compensatory – kidney removal
Pathological:
- prostatic hypertrophy and hyperplasia
- parathyroid hyperplasia
- thyroid hyperplasia
Define metaplasia and describe pathways by which this process may occur
Reversible change from one adult cell type to another adult cell type.
NOTE: In terms of neoplasia, malignancy often preceded by metaplasia
Adaptive response
Pathways:
- Usually arises by a proliferation and transformation of immature stem cells or undifferentiated mesenchymal cells along a different pathway.
- Brought about by changed in signals
Causes:
- trauma
- chronic irritation/inflammation
- hypovitaminosis A
- Cigarette smoke
Give examples of metaplasia in various tissues and explain the significance of this process.
- Respiratory tract – squamous metaplasia
- smoking
- chronic infection
- Bladder, renal pelvis, cervix – squamous metaplasia
- chronic irritation/infection
- Stomach and oesophagus – goblet cell metaplasia
- chronic inflammation
What is a neoplasm?
- An abnormal mass/new (neo-) growth of tissue
- Growth is not co-ordinated
- Persists after removal of inciting stimulus (if any is identified)
- May have secondary changes: e.g. ulceration
Define adenoma
A benign epithelial neoplasm that forms glands OR which derives from glandular tissue
Define papilloma
A benign epithelial neoplasm characterised by the formation of finger-like projections from the epithelial surface
Define teratoma
A tumour composed of ecto, endo and/or mesoderaml tissues, usually multiple, foreign to the site of origin.
Definae hamartoma
A tumour-like malformation composed of differentiated tissues normal to the site of origin. (iris, pulmonary, renal)
NOT a neoplasm
Define blastoma
A tumour composed of embryonic cells – very primitive cells
Define choristoma
A mass of histologically normal tissue in an abnormal location
NOT a neoplasm
Define polyp
Any growth or mass protruding from a mucous surface
It may not be a neoplasm
Define tuberculoma
A tumour-like mass resulting from the enlargement of a caseous tubercle.
NOT a neoplasm
Define mycetoma
A chronic disease due to infection by various fungus or actinomycetes affecting the foot, hands, legs or internal organs.
NOT a neoplasm.
Define anaplasia
A condition of cells in which they have poor cellular differentiation, losing the morphological characteristics of mature cells and their orientation with respect to each other and to endothelial cells.
Define pleomorphism
Pleomorphism is a term used in histology and cytopathology to describe variability in the size, shape and staining of cells and/or their nuclei. It is a feature characteristic of malignant neoplasms, and dysplasia.
Define metastasis
The development of secondary malignant growths at a distance from a primary site of cancer.
What does carcinoma refer to?
Malignant epithelial
What is cancer?
Malignant neoplasm
A tumour having the properties of anaplasia, invasiveness and metastasis.
What does sarcoma refer to?
Malignant mesenchymal
Define dysplasia
The enlargement of an organ or tissue by the proliferation of cells of an abnormal type, as a developmental disorder or an early stage in the development of cancer.
What factors are used to classify neoplasms?
- Behavioural
- Histogenetic
- Descriptive
- Site of origin
- Embryological – ecto, endo or mesodermal
- Aetiological – usually not known
- Molecular – emerging. I.e. HER 2, BRAF ALK positive
What is the difference between benign and malignant?
Benign – remains localized
Malignant – not localized. Can be primary or secondary
What is the difference between hyperplasia, dysplasia and neoplasia?
In hyperplasia, there is an increase in the number of cells in an organ or tissue that appear normal under a microscope. In dysplasia, the cells look abnormal under a microscope but are not cancer. Hyperplasia and dysplasia may or may not become cancer.
Neoplasia is the development of a tumor, which means cell division is not being controlled.
What are the key macroscopic features of benign tumors (vs malignant)?
- may have a capsule and be circumscribed
- no invasion
- uniform, less haemorrhagic
- rarely necrotic
- grows slower
What are the key microscopic features of benign tumors (vs malignant)?
- well differentiated
- low nucleus: cytoplasm ratio
- usually not pleomorphic (variability in size and shape of cells) (but exceptions)
- low mitotic rate
- no invasion (exceptions)
- no metastasis
What are the key macroscopic features of malignant tumors (vs benign)?
- tends not to have a capsule and may not be circumscribed
- invasion
- necrosis common
- haemorrhage common
- grows faster
What are the key macroscopic features of malignant tumors?
- variable differentiation
- high nucleos: cytoplasm ratio
- pleomorphism
- hyperchromasia
- variable mitotic rate, abnormal mitosis
- necrosis
- invasion
- vascular invasion
- reaction to invasion (desmoplasia – growth of fibrous or CT)
What are the four key features that differentiate benign and malignant tumors?
- Differentiation – benign is well
- Rate of growth – benign is slow
- Local invasion – none for benign
- Metastases – no for benign
What is differentiation and what are the different types of differentiation?
The extent to which neoplastic cells resemble comparable normal cells morphologically and functionally
a) well differentiated – tumor cells resemble mature normal cells (benign)
b) Intermediate – moderately differentiated
c) Poorly differentiated/undifferentiated – poor or no resemblance
d) Anaplasia – extreme lack of differentiation
What factors does tumor grade depend on?
High grade (poor, undifferentiated) vs low
- differentiation
- nuclear pleomorphism
- mitotic rate
- vascular proliferation
- necrosis
- others, i.e. proliferation index
What are some of the biochemical markers of cancers?
- HER2 – breast, stomach
- BRAF – melanoma, colon, rectum, thyroid
- EGFR – lung
- KRAS – colon, rectum, pancreas
- ASLK positive – lung
- Oestrogen and progesterone receptors – breast
Allows for target therapy
What are pre-cancerous lesions?
Premalignant lesions are morphologically atypical tissue which appears abnormal under microscopic examination, and in which cancer is more likely to occur than in its apparently normal counterpart.
- Either dysplasia or benign tumor.
- Confined to the epithelium
- Morphological expression of disturbance of growth regulation
- Individual cells similar to malignant cells
- Pre-neoplastic lesion
- Low vs high grade
- Carcinoma in situ – very severe dysplasia
How pre-cancerous lesions progress to malignancy?
- lesions are first localized, often asymptomatic
- penetrate the basement membranes/capsules
- movement through extracellular matrix
- penetrate vascular channels (most cells don’t survive journey)
- exit to new tissue
- survival and growth as metastasis evoking angiogenesis
How can cancer spread?
- local direct invasion
- lymphatic dissemination
- haematogenous dissemination
- spread across cavities
- intraepithelial spread
- others – implantation, fine needle aspiration tract
What is the aetiology of neoplasms?
- genetic
- chemical
- hormonal
- radiation
- microbial organisms
- chronic diseases (i.e. ulcers)
- immune system disorders
What are the genetic predispositions of cancer?
a) autosomal dominant inherited cancer syndromes
b) Defective DNA repair syndromes and resulting DNA instability (lynch)
c) Familial cancers (breast, colon etc)
What are the non hereditary predisposing factors of cancer?
- Non neoplastic:
- chronic atrophic gastritis
- solar keratosis of the skin
- ulcerative colitis
- Barrett disease - Neoplastic:
- benign neoplasms
- dysplasia
What are some carcinogenic agents?
a) chemical
b) radiation
i) UV – squamous and basal cell carcinoma melanoma
ii) ionizing radiation
c) oncogenic viruses and other microbes
- HepB – liver cancer
- EBV – Burkitt’s lymphoma, nasopgaryngeal carcinoma
- HPV - carcinoma of cervix
- H. pylori – gastric carcinoma and lymphoma
Provide a scheme of cancer staging and tumour grading.
TNM cancer staging (site dependant): - T: tumor - size - extent of spread - N: Nodal status - number - groups - size etc - M: Metastasis Eg. T3N1M0
Clinical staging: I, II, III, IV
Provide an overview of the epidemiology of cancer in WA.
5 leading primary tumor sites for cancer mortality:
- lung (M+F)
- colorectal (M)
breast (F) - prostate (M)
colorectal (F) - Melanoma (M)
Pancreas (F) - Unknown primary
What are some of the effects of all neoplasms?
- local/pressure effects
- abnormal functional activity
- obstruction of vessels, tubes and ducts
- bleeding, secondary infection by ulceration
- rupture of blood vessels
- pain
- raised intracranial pressure
Benign tumors are rarely responsible for death directly.
Malignant can also:
- metastasize
- replace/destroy native tissue/organs by crowding or invasion
- cachexia (wasting)
- paraneoplastic syndromes
- psychological effects
- effects of therapy
What are the Bradford Hill Considerations of data?
- strength of association
- consistency of the observation (reproducibility)
- specificity to a disease
- temporality (cause before disease)
- gradient (dose-response)
- plausibility (biology)
- coherence (with natural history of disease)
- experimentation (with significance)
- analogy (similar known causes)
How can carcinogens in cigarette smoke cause cancer?
- metabolic activation by ‘DNA adduct’
- Direct DNA damage
What is an example of a gene mutation found in tobacco-induced cancer?
- P53 mutation*
- LRAS
- PTEN
How does smoking increase cardio vascular disease risks?
A. development of atherosclerotic changes
- chronic inflammation
- lipid abnormalities
- endothelial dysfunction
B. induction of hypercoagulable state
What are common examples of occupational exposure to chemical and physical agents?
- carbon monoxide
- asbestos
- lead
- UV radiation
How does asbestos cause disease?
- direct interaction with cells
- reactive oxygen species – macrophages attempt to digest it
- chronic inflammation
What are some asbestos related diseases?
- Asbestosis (fibrosis)
- Mesothelioma
- Adenocarcinoma – massive risk increase with smoking
What are some of the consequences of lead poisoning?
a) Acute
- GIT pain (colic)
- demyelination neutopathy (weakness)
b) Chronic
- decreased IQ
- cognitive decline
- renal dysfunction
- anemia
- hypertension
What are some gaseous air pollutants and what can they lead to
- ozone
- sulfur dioxide
- nitrogen dioxide
Can lead to:
- production of free radicals
- airway reactivity
- lung inflammation
Why can carbon monoxide be a problem?
- Hb has 200x greater affinity for CO than O2
- CNS ischemia
What are some of the consequences of UV radiation?
- sunburn
- collagen damage
- carcinoma/melanoma
What is hyperthermia and what are the consequences?
Core 41-42 degrees
Consequences:
- confusion
- cardiac and respiratory dysfunction
- vasodilation
- oedema
- clotting
- acidosis
- denaturation of cell proteins
What is hypothermia and what are the consequences?
Core 35 degrees
Consequences:
- confusion
- loss of shiver response
- diuresis
- cardiac arrhythmia
- pulmonary oedema
What are some examples of physical environmental agents that cause disease?
- burns
- trauma
- electrocution
- ionizing radiation
- nutritional:
a) obesity
b) malnourishment
What is cytology and what are the 3 main areas?
Morphological study of cells by themselves
- gynaecological (pap smears)
- non- gynaecological
- fine needle aspiration (FNA)
What is a pap smear and why is it used?
- cells from transformation zone of cervix obtained via spatula or brush
- smeared onto slide, fixed and stained using papanicolaou method
- +/- liquid based technique
- diagnosis of inflammatory conditions
- candida
- trichomonas
- Diagnosis of viral infections
- HSV
- HPV
- Malignant lesions and their precursors
- CIN 3 (cervical intraepithelial neoplasia)
- squamous cell carcinoma
For non-gynaecological cytology, what specimen types can be taken?
a) Fluids
- pleural
- peritoneal
- pericardial
- CSF
- urine
b) Brushings
- bronchial
- bile duct
c) Washings
- peritoneal
- bladder
- renal pelvis
Should non-gynaecological cytology samples be fixed or unfixed?
Either
If unfixed – should be refrigerated to prevent degeneration of cells
If fixed – alcohol fixative (95% ethanol)
Why is non-gynaecological cytology done?
To diagnose: - inflammatory conditions - infections - malignancy To exclude malignancy
Example – haematuria (blood in urine) – urologist performs cystoscopy and sees tumor and takes biopsy.
What can be assessed by FNA?
Virtually any organ or mass Either direct (superficial and palpable) or under image guidance (ultrasound or CT)
How is a FNA sample produced?
- material obtained smeared on slides
- fixed and air-dried
- cell block and be made for ancillary studies
What is tissue pathology (histopathology) and what types are there?
The microscopic examination of tissue in order to study the manifestations of disease.
a) Biopsies
- skin, breast, GIT, liver, kidney, cervix, brain
b) Surgical excisions
- inflammatory/infectious/infarct
- benign neoplasm
- malignant neoplasm
/What is the lab process for specimens?
- Specimen received with request form:
- patient details
- specimen location
- clinical info
- requesting doctor - Specimen fixed in 10% neutral buffered formalin
- Examined by pathologist
- Required tissue selected and placed in cassettes
- Processed overnight then embedded in paraffin wax
- Paraffin block sectioned
- Section transferred onto slide
- H&E stain
- Examination
- Report issued
What is histopathology used to diagnose?
- inflammatory conditions
- infections
- benign neoplasms
- malignant neoplasms
In histopathology, how are microbes studied?
Fresh tissue required for organism culture and providing antibiotic sensitivities.
- bacteria: gram stain
- H. pylori: Toluidine blue
- Giardia: giemsa stain
- Fingi: silver stain
- Mycobacteria: Ziehl Neelsen
Also special stains for iron, mucin and elastin.
What are the types of malignant lesions?
- Carcinoma (epithelial tissue of skin of lining of internal organs)
- squamous cell
- adenocarcinoma
- neuroendocrine - Sarcoma (CT or other non-epithelial tissue)
- Melanoma (melanin forming cells)
- Lymphoma (lymph nodes)
What is immunohistochemistry and what is it used for?
TUMORS. Uses antibodies to detect different antigens in the tissue sections.
Used to:
- differentiate between different tumor types
- determine site of primary tumor in metastatic lesions
- measure of proliferative activity in tumors
- determine tumor response to treatment
How is a breast carcinoma diagnosed?
Triple test:
- clinical
- radiology
- histopathology
- core biopsy
- post surgical excision
For a breast carcinoma, what does histopathological assessment of the surgical excision determine?
- tumor type and grade
- invasive vs in situ
- presence/absence of lymphovascular space invasion
- adequacy of surgical excision
- lymph node status
What is immunohistochemical staining used to determine in breast carcinomas?
- oestrogen and progesterone receptors
hormone therapy: tamoxifen and aromatase - HER2 staining
therapy: herceptin
Common causes of iron deficiency:
a) blood loss
- GI
- menstrual
- other
b) inadequate intake – vegetarian
c) Inadequate absorption
- coeliac disease
- gastritis
- calcium impairs absorption
- ascorbic acid aids absorption
d) Increased requirements
- pregnancy
- children
Common causes of iron overload:
a) Hereditary
- HFE haemochromatosis (type 1)
- non-HFE haemochromatosis (type 2-5)
b) Acquired
c) Iron loading anemias
- thalassaemia major
- sideroblastic anemia
- chronic haemolytic anemia