Neoplasia 1 Lecture Flashcards
(44 cards)
Define neoplasia
New growth
- Tumor is an abnormal mass of tissue, the growth of which is virtually autonomus and exceeds that of normal tissues –> persists after cessation of the stimuli that initiated its change
All tumors have two components?
Parenchyma (proliferating neoplastic cells) Supporting stroma (connective tissue and blood vessels
Benign tumors?
End with “oma”
- has the same characteristics as its’ parent
Adenomas
Benign epithelial tumors arising in glands or forming grandular patterns
Cystadenomas
Adenomas producing large cystic masses, typically in ovaries
Papillomas
Epithelial tumors forming microscopic or macroscopic finger-like projections
Polyp
A tumor projecting from the mucosa into the lumen of a hollow viscus
- Macroscopically visible projections above a mucosal surface
Malignant Tumors
Cancerous tumors
- Mesenchymal tissues - sarcomas (fleshy because of little stroma) or epithelial- carcinomas
Malgnant tumors classification
With glandular growth patterns - adenocarcinoma
- Recognizable characteristics of cells found than so named - squamous cell carcinoma
- Not recognizable- poorly differentiated or undifferentiated - carcinoma
- Sometimes mixed tumors (tumor of salivary gland origin
Characteristics of neoplasms
Distinction between benign and malignant tumors is based on the appearance (morphology) and ultimately on behavior (clinical course)
Define differentitation
Extent to which tumor cells resemble comparable normal cells
- Benign tumors are well differentiated (look like a normal cell)
- Malignant neoplasms are in general less well differentiated than benign
Anaplashia
Lack of differentiation (hallmark of malignant cells)
Features of Anaplasia
Nuclear and cellular pleomorphism Hyperchromatism Nuclear-cytoplasmic ratio Abundant mitoses Tumor giant cells Loss of polarity
Nuclear and cellular pleomorphism
Wide variation in the shape and size of cells and nucleus
Hyperchromatism
Darkly stained nuclei that frequently contain prominent nucleoli
- Much larger than normal cells
Nuclear-cytoplasmic ratio
1:1 instead of 1:4 or 1:6, reflecting enlargement of nuclei
Abundant mitoses
Reflect proliferative activity, mitotic figures may be abnormal
- All different versions of mitosis
Tumor giant cells
Contain a single large polyploid nucleus or multiple nuclei
Loss of polarity
Poorly differentiated, anaplastic tumors also demonstrate a total disarray of tissue architecture
- Lost differentiation
Define dysplasia
Disorderly but non-neoplastic growth (mild degrees of dysplasia, but do now always leading to cancer and are often reversible when the inciting cause is removed
- Usually in the epithelial, involve the entire thickness (can be considered a preinvasive neoplasm –> carcinoma in situ)
- Forerunner in may cases of invasive carcinoma
Rate of growth
Malignant tumors grow more rapidly than benign tumors
- Some cancers grow slowly for years and then enter a phase of rapid growth
- Growth of cancers arising from hormone sensitive tissues… May be affected by variations in hormone levels associated with pregnancy and menopause
Rapidly growing malignant tumors often contain
Central areas of ischemic necrosis because the tumor blood supply falls to keep pace with the oxygen need of the expanding mass of cells
Local invasion of benign tumors
Grow as cohesive expansile masses that develop a rim of condensed connective tissue or capsule at the periphery (do not invade, they are encapsulated)
- Surgical enucleation: plane of cleavage between the capsule and the surrounding tissues
Local invasion of malignant tumors
Invasive, infiltrating, and destroying normal tissue surrounding them
- Lack a well-defined capsule and plane of cleaving, making enucleation difficult or impossible
- Surgical treatment of such tumors requires removal of a considerable margin of healthy uninvolved tissue
