Flashcards in Intro to Neoplasia Deck (20):
An abnormal mass of tissue, the growth of which exceeds and is uncoordinated with that of normal tissues and persists in the same excessive manner after cessation of the stimuli that envoked the change.
Used interchangeably with tumor.
Both DO NOT equal cancer.
Describe the differences between benign and malignant tumors.
Benign: usually resemble normal tissue, slow growth rate, non-invasive, encapsulated; do not metastasize
Malignant: vary from resembling normal tissue to extremely different, variable growth rate, usually invasive, capable of metastasizing. -carcinoma or -sarcoma.
arise from ecto- or endoderm
squamous, glandular/ductal, respiratory and transitional epithelium, liver cells, and basal cells of skin/adnexa
arise from mesoderm
fibroblasts, adipocytes, smooth/skeletal muscle, bone, cartilage, blood vessels
Lymphoma, leukemias, plasmacytoma, pseudolymphoma, malignant tumors
neural crest origin
Benign mixed tumors
Epithelial and mesenchymal components
Commonly in parotid gland
Composed of tissue derived from multiple germ layers -- totipotent cells
Mass of disorganized, mature tissue which is specific to the site of development
Ectopic tissue in a foreign location
Extent to which tumor cells morphologically and functionally resemble the normal tissue counterpart
Well-differentiated: resembles normal tissue
Poorly-differentiated: primitive, vague resemblance
Anaplastic: complete lack of differentiation
Benign tumors are well-differentiated; malignant tumors vary from well- to poorly-differentiated/anaplastic
What are some characteristic features of anaplasia?
High N/C ratios
Coarsely clumped chromatin
Atypical, bizarre mitoses (tripolar)
Loss of polarity
Tumor giant cells
Carcinoma in situ (CIS)
Seen in proximity to invasive tumor
Malignant cells do not penetrate beyond basement membrane
Full thickness dysplasia (disordered growth)
Characteristics of dysplasia
Loss of polarity
Loss of maturation
Loss of architecture/organization
Abnormally located mitoses
Varies from mild to severe (CIS)
Mild to moderate may spontaneously resolve
1. loosening of intracellular junctions
2. attachment at different sites
Malignant tumors metastasize except for...
Basal cell carcinoma and gliomas
Pathways for metastatic spread
Hematogenous (most common for sarcoma spread)
Lymphatics (most common for carcinoma spread)
Seeding of body cavities and surfaces (peritoneal cavity)--Tumor cells displace from mass and implant and/or invade serosal surfaces
First LN to drain the tumor
TNM system for clinical stage
T= tumor size
N= nodal involvement