Intro to Neoplasia Flashcards
Define tumor
Classically defined as swelling but often used interchangeably with neoplasia
DOES NOT MEAN CANCER
Define neoplasia
Abnormal “new growth”
An abnormal mass of tissue, the growth of which exceeds and is uncoordinated with that of the normal tissues and persists in the same excessive manner after cessation of the stimuli which evoked the change
DOES NOT MEAN CANCER
Define dysplasia
Disorderly proliferation
Define anaplasia
Lack of differentiation (cells don’t match their surroundings)
How can you classify a tumor?
Based on its:
- Cell of origin (epithelial, mesenchymal, CNS, lymphoid)
- Differentiation (well, moderately, poorly)
- Behavoir (benign/malignant)
What are examples of tumors classified by their cell of origin?
- carcinoma= epithelial (most common)
- sarcoma= mesenchymal (rare)
- lymphoma, leukemia= hematolymphoid
- melanoma= melanocytic
- glioma/schwanoma= CNS
- carcinosarcoma= mixed
What characteristic is necessary to classify a cancer as invasive?
Cancer needs to break through the basal lamina below the epithelial cells
What is an adenocarcinoma?
A cancer of glands (epithelial)
What are features of epithelial cell origin cancers?
- typically arise from ectoderm or endoderm germ layers
- benign or malignant
- further classified based on architecture (papillary/bumpy, villous/flat with projections, sessile/flat and deep, cystic)
Contrast a carcinoma and sarcoma
Carcinoma= epithelial origin
Sarcoma= mesenchymal/connective tissue origin
What cells are in the mesenchyme and can become cancerous? What is the nomenclature of benign versus malignant mesenchymal cancers?
Fibroblasts, adipocytes, smooth/skeletal muscle, bone, cartilage, blood
Benign= -oma
Malignant= -sarcoma
E.g. Osteoma versus osteosarcoma
What are the categories of hematolymphoid origin cancers and examples of each?
- Lymphoid (cancer resembles lymphocyte; lymphoma)
- Myeloid (cancer arises from granulocyte/RBC/platelet progenitor cells; myeloid leukemia)
- Histiocytic (proliferative lesions of macrophages and DCs; histiocytoses)
What is a “blast”?
A lymphoblast/lymphocyte progenitor cell
What are characteristics of melanocyte origin tumors?
- Neural crest origin
- May be benign (nevus; defined structure) or malignant (melanoma; varrigated/irregular border)
What are characteristics of a benign tumor?
- “-oma”
- usually resemble normal tissue
- slow growth rate
- non-invasive growth, encapsulated
- do not metastasize
What are characteristics of a malignant tumor?
- cariconmas or sarcomas
- variable morphology (normal to extremely different)
- variable growth rate
- invasive growth pattern (nonencapsulated/irregular shape)
- capable of metastasizing (except basal cell carcinoma and gliomas)
What 4 criteria are used to determine a benign versus malignant tumor?
- differentiation and anaplasia (extent to which tumor cells morphologically and functionally resemble the normal tissue counterpart)
- rate of growth
- local invasion
- metastasis
What are the histological features assoicated with malignancy?
- cellular/nuclear pleomorphism
- coarsely clumped chromatin
- hyperchromatic nuclei
- high nuclear to cytoplasmic (N/C) ratio
- large nucleoli
- atypical, bizarre mitoses (bi/tripolar)
- loss of tissue polarity (loss of apical/basal layers)
- tumor giant cells
**these features contribute to the cancer GRADE
What are the two ways tumor giant cells can form?
- Cell doesn’t undergo cytokinesis
- Cells fuse together
Define mixed tumor
A tumor with multiple morphological components (e.g. epithelial and mesenchymal)
Define teratoma
Composed of tissue derived from multiple germ layers- totipotent cells
**predominately benign tumors
Define hamartoma
A tumor-like condition;
- mass of disorganized, mature tissue which is specific to the site of development (surrounded by normal tissue)
- represent anomalous development (correct cell structure and location, just weird organization/arrangement)
- e.g. lung hamartoma
Define choriostoma
A tumor like condition;
- ectopic tissue in a foreign location
- e.g. gastric heterotopia= gastric mucosa in the large intestine
**Normal tissue orientation/arrangement in a weird place
Contrast in situ and invasive tumors
In situ= above basil lamina
Invasive= infiltration of the basil lamina (local is potentially curable while metastatic is unlikely to be cured)
How do tumors invade the ECM? (steps)
- Loss of E-cadherin function (cell-cell adhesion)
- inactivation of E-cadherin
- activation of beta catenin
- SNAIL/TWIST transcription factors
- Degradation of basement membrane (matrix metalloproteinases/MMPs)
- Change in attachment of tumor cells
- Migration
Where are common sites of metastases?
- lymph nodes
- lungs
- liver (commonly from colon)
- bone/vertebra
- brain (commonly from lung)
Describe the common hematogenous metastatic spread
**common pathway for sarcoma spread (veins>arteries)
- portal -> liver
- vena cava -> lung
- paravertebral plexus -> vertebral mets
Describe the common lymphatic metastatic spread
- most common pathway for carcinoma spread (rarer with sarcomas)
- lymph node involvement is predictable based on drainage (sentinel node= first LN to drain the tumor)
Describe the TNM staging system
TNM=
- tumor size
- nodal involvement
- metastasis
*each cancer type has its own classification system
_**STAGE IS NOT GRADE_ (management of cancer is determined by stage; I, II, III, IV)
What is the common host response to cancer?
- local effects
- compression of vital structures; pituitary
- ulceration (bleeding, infection)
- cachexia (weight loss)
- cytokine release rather than reduced food intake **TNF
- hematologic abnormalities
- anemia
- hypercoagulability
What is the physical effect of cancer?
**paraneoplastic syndromes in 10% of patients;
- Cushing’s (ACTH)
- Hypercalcemia (PHrP, TGFa, TNF, IL1)
- Nonbacterial thrombotic endocarditis (hypercoagulability)
- Carcinoid syndrome (serotonin, bradykinin)
