Neoplasia 1 Flashcards
1
Q
tumour
A
- neoplastic lesions which are benign or malignant
2
Q
neoplasia
A
- new growth where growth/proliferation of cells is uncontrolled
- includes both cancerous (malignant) and benign lesions
- begins in a single cell
- adult stem cells, progenitor cells, or transit amplifying cells
- generally involves mutations affecting the cell cycle, cell proliferation, characteristics, and behaviour
- eg protoncogenes, TSGs
- can be mutations to apoptotic and DNA repair pathways
- involves acqusition of other features that enable progression:
- ability to dissociate, allowing for metastasis
- motility to move through tissues (metastasis)
- release of factors such as VGEF (angiogenesis)
3
Q
oncology
A
- study of neoplastic lesions and cancer
- surgical or medical specialty relates to management of patients with cancers and malignancies
4
Q
benign
A
- proliferate slowly
- generally do not cause major disease
5
Q
dysplasia
A
- abnormality of development
- alteration in size, shape, and organization of cells
- congenital dysplasias are not premalignant
- epithelial dysplasias are premalignant
6
Q
premalignant
A
- cells that are not yet malignant but have a reasonable chance of becoming malignant
- they are non-invasive precursors of malignancy
- if dx and tx they can prevent malignancy from developing
- this is largely relevant to carcinomas (cancers arising in the epithelium), the most common type of cancer
7
Q
intraepithelial neoplasia
A
- eptihelial dysplasia
- many invasive carcinomas thought to arise as a result of progression and invasion of these premalignant epithelial lesions
- can be graded:
- mild/mod/severe, or grades 1-3:
- grade 1 - less likely to progress to invasive malignancy
- grade 3 - severe, more likely
- implications for tx
- mild/mod/severe, or grades 1-3:
8
Q
carcinoma in situ
A
- severe or Grade 3 dysplasia
- cells show significant cytological atypia and appear malignant
- cells are still in-situ and have not invaded through the BM into the underlying stroma
- more likely to progress
9
Q
malignant
A
- rapidly, aggressively, and uncontrolalby proliferating cells
- can invade and destroy other tissue
- can metastasize
10
Q
cancer
A
- common term for malignant leisions:
- can invade and metastasize
- malignant generally the type which causes death
- benign is far less common
11
Q
uncertain malignant potential
A
- only seen in certain organs eg ovary
- difficult to determine histologically whether they are malignant or benign
- particular features that overlap
- some may be low-grade maligancies, others benign
- difficult to predict behavour
- few metastasize
12
Q
anaplasia
A
- extreme of poorly differentiated cells
- difficult to tell which cell lineage they are from
13
Q
metastasis
A
- spread of cancer cells throughout the body
- occurs via:
- lymphatic route
- haematogenous route (blood)
- transcoelemic route (peritoneal, pericardial, pleural cavities)
14
Q
What are the differences between benign and malignant neoplastic lesions?
A
natural history, potential complications, morphology
- benign lesions proliferate slowly and generally do not cause major disease
- malignant lesions proliferate rapidly, aggresively, and uncontrollably
- they can invade and destroy tissue, and metastasize to other tissues
- there are some highly aggressive and less aggressive malignancies
- there are lesions in the middle of this continuum that are not defined as either benign or malignant = borderline
15
Q
What macroscopic and microscopic features distinguish beningn and malignant lesions? What are the exceptions?
A
Benign
- locally expansile, slow growth, often well cicumscribed (+/- encapsulated)
- well differentiated cells
- appear similar to mature, fully-differentiated cells
- unable to metastasize
- rarely life-threatening (depending on site)
Malignant
- locally invasive, rapid destructive growth, often poorly circumscribed
- induce desmoplasia in stroma as they invade
- release of cytokines and growth factors (TGFb) from malignant cells induce surrounding fibroblasts to proliferate, ++ECM within and around the tumour cells
- sometimes necrosis if outgrows glood supply, some apoptosis
- variable differentiation: well, moderate, poor, anaplastic
- potential to metastize
- lymphatic, haematogenous, transcoelomic (pleural, peritoneal, pericardial cavities)
Exceptions:
uncertain malignant potential/borderline
- only certain organs eg ovary
- features overlap between benign and malignant
- few metastasize
16
Q
What are the common routes of metastases?
A
lymphatic spread
- spread to local lymph nodes via lymphatic vessels
- travel to other lymphatics
- can enter venous system via thoracic duct (haematogenous spread)
haematogenous (blood-borne) spread
- access blood via capillaries, into the venous system
- can spread to lungs, brain, bones
transcoelomic spread
- spread along body cavities (pleural, peritoneal, pericardial)
- commonly associated with excess fluid production from serousal capillaries
- ascities, pleural effusion
17
Q
What are the common sites of metastases?
A
- liver
- brain [melanoma]
- lungs
- bone [prostate]
- within organ
18
Q
What is glandular differentiation?
A
- differentiation from glandular cells of the epithelial cell line
- prefix is adeno-
- tumour cells that form glands or lumina, contain or secrete mucin
19
Q
What is squamous differentiation?
A
- refers to stratified squamous differentiation, not simple
- intracellular bridges form spikes of tissue between cells
- keratinization can be internal swirls rather than just on the surface
20
Q
What is smooth muscle cell differentiation?
A
- tumour cells that differentiate from a smooth muscle (mesenchymal) cell line
- they appear like smooth muscle cells
- elongated nuclei with rounded ends
- cells are elongated
- prefix is leiomyo
21
Q
How are cancers named?
A
- Prefix refers to line of differentiation or cell linage:
- Adeno = glandular
- squamous cell
- leiomyo = smooth muscle
- osteo = osteoid forming
- Suffix refers to:
- benign -oma
- malginant:
- -carcinoma if epithelial
- -sarcoma if mesenchymal
-
there are many exceptions
- eg seminoma - malignant testicular tumour from germ cells; lymphoma - malignant lymphatic neoplasias
- examples:
- adenoma = benign glandular lesion
- adenocarcinoma = malignant glandular epithelial lesion
- leoimyoma = benign smooth muscle lesion
- leiomyosarcoma = malignant smooth muscle mesenchymal lesion
22
Q
What is the degree of differentiation, and how is this determined?
A
- determined histologically
- neoplastic lesions are generally classified as well, moderate or poorly differentiated, or anaplastic
- well:
- closelet resemble mature cells (less cytologic atypia, less mitotic activity)
- less architectural disorganization
- poorly:
- poorly resemble mature cells (more cytologic atypia, more mitotic activity +/- atypical mitoses)
- more architectural disorganization
- anaplastic:
- extremely poorly differentiated cells
- cannot tell lineage of origin
- well:
- differentitiation in malignant tumours is referred to as its grade
- benign are typically well differentiatied
- malignant can be any
25
Q
What is the role of dysplasia/intraepithelial neoplasia in carcinogenesis?
A
eg in gut
- normal layer of simple columnar epithelial cells with small uniform nuclei
- 1 stem cell or progenerate cell starts to mutate and proliferate out of control
- see more mitotic figutes
- nuclei become larger and more pleiomorphic
- nuclear changes progess and become more severe
- architectural disorganization occurs and eventually the lesion invades the BM
- apical cells now seen in the adjacent stroma
- cells must release enzymes such as matrix metalloproteinases to break down the BM collagen
26
Q
What are the morphological features of dysplasia/intraepithelial neoplasia in carcinogenesis?
A
- enlarged pleoimorphic nuclei
- disorganised cells
- increased proliferation
- incomplete cellular maturation
28
Q
What are the original hallmarks of cancer?
A
- sustaining proliferative signalling
- evading growth suppressors
- activating invasion and metastasis
- enabling replicative immortality
- inducing angiogenesis
- resisiting ceal death
29
Q
What are the histopathological features of neoplastic cells?
A
- cytological atypia:
- larger, pleomorphic nuclei
- coarser nuclear chromatin (clumping rather than fine distribution)
- hyperchromatic nuclei (stain darker with H due to additional DNA, chromosomes)
- larger, more prominent nucleoli (more active)
- more mitotic activity, abnormal mitotic features
- architectural disorganization
30
Q
neoplastic cells
A
enlarged nuclei, prominent nucleoli, nuclear pleomorphism
31
Q
What do the arrows indicate?
A
mitotic figures; these cells are neoplastic and hyperchromatic
32
Q
What is desmoplasmic stroma?
A
- only seen in invasive malignant tumours
- stroma is abnormal
- between tumour cells, not just around them
- highly cellular (lymphocytes, macrophages, fibroblasts)
- induced by desmoplasia, the release of cytokines and growth factors from cancer cells that promote fibroblast activity
33
Q
What type of necrosis is associated with cancerous cells (if present)?
A
- typically not coagulative
- see pynknotic (condensed) or karreorhectic (fragmented) nuclei
