Terminology and classification of tumors Flashcards
Clinicopathologic groups:
- preneoplastic/dysplastic lesions
- neoplasias
- tumor-like lesions
Types of neoplasias
- benign
- semimalignant (borderline)
- in situ carcinoma
- malignant
Nomenclature of tumors
benign neoplasias are usually called by tissue of origin with “-oma” at the end (lypoma)
Can be tricky because malignant tumors also can end eitj -oma (lymphoma) or tumor-like lesions (granuloma, haematoma, actinobacilloma)
Epithelial malignant tumors are usually called …
carcinoma
Mesenchymal malignant tumors are usually called …
sarcoma
What does ending -blastoma mean in case of tumor?
highly undifferentiated tumors (nephroblastoma, retinoblastoa etc)
Dysontogenic tumors - ?
individual category somewhere between neoplasias and developmental anomalies
2 big groups of dysontogenic tumors
Choristoma and Hamartoma
Choristoma
type of heterotopia. Normally differentiated tissue developed at a WRONG LOCATION
Hamarthoma
Focal malformation. Abnormally differentiated tissue at anatomically normal location.
Teratomas are kind of hamarthomas
Teratoma
…
Differentiation of neoplasias?
More differentiated tumor is, more it resembles tissue of origin, more benign characteristics it has
Benign vs. Malignant basic characteristics
- localized (capsule), slower growth, well-removable, no recurrence usually <-> faster growth, invasion into surrounding tissues
- no invasion or metastasis <-> metastasis to distant organs
- can cause compression but usually does not harm patient’s life <-> can cause death
- benign tumors are genetically “simple” and stable (less mutation and less variation in genetic structure over time)
Can types of tumors overlap?
Yes. Criteria for differentiation are:
- differentiation
- pace of growth
- local invasion
- metastasis
Can benign tumors become malignant?
Yes they can. Also there can be functional malignancy
Is it always possible to distinguish between malignant and benign tumors?
No. E.g. tumor is growing, invading the tissue but doesn’t give metastasis -> SEMIMALIGNANT TUMORS
Semimalignant tumors
Have mostly characteristics of benign tumors BUT they are locally invasive, infiltrating surrounding tissues ! also tend giving recurrence
NO metastasis
In situ carcinoma - ?
- Pre-invasive phase of an epithelial malignancy
- localized process
- proliferation will no go through basement membrane !! (won’t affect dermis)
- skin -> Bowen or multicentric in situ carcinoma
- mammary gland -> intraductal and intralobular carcinoma
- in case of mucosas - if it does not go through lamina muscularis mucosae
- important to make several slides !!
Neoangiogenesis
- Neoplasm will form new small blood vessels that will be O2 source for tumor.
- if cell proliferation rate > rate of neoangiogenesis -> hypoxia -> necrosis
Grade of differentiation
Level of cell differentiation of the tumor’s parenchyma is variable
-G1 well-differentiated
-G2 moderately differentiated
-G3 Poorly differentiated / anaplastic
(growing ability, invasion ability, prognosis of disease, therapy modality)
Anaplasia - ?
lack of differentiation. Tissue will lose original functions but can gain new ones.
Characteristics of anaplasia:
- anisocytosis, anisokaryosis, kariomegaly, increased nuclear:cytoplasmic ratio, hypo/hyper chromasia,
- prominent NUCLEOLUS,
- increased mitotic activity,
- irregular chromosomes
Anisocytosis - ?
Difference in size and shape of cells
Anisokaryosis - ?
Variation in nuclear size and shape
Karyomegaly - ?
enlargement of the nucleus (2-3x normal size)
Nuclear : cytoplasmic ratio
nuclei- cell and nuclear cytoplasm ratio 1:1 instead of 1:4/1:6
Hypo- / hyperchromasia
Lack or hyper staining of the nuclei
pre-neoplastic lesions
Genetic deformities can be already marked with molecular methods but there are no clinical signs
reversible pre-neoplastic lesions (dysplasia, metaplasia) are frequently precursors to neoplastic progression
Acquired pre-neoplasia
some chronic regenerative cell proliferation (e.g. liver cirrgosis)
Tumor-like lesions. Examples
- macroscopically look like tumors
- e.g.
- idiopathic nodular hyperplasia (liver, pancreas, spleen, adrenal gland)
- cystic mucinous hyperplasia in gall bladder
- chronic inflammatory tissue proliferation
- hyperregeneration
- follicular cyst in skin
