Neoplasia I Flashcards
Define neoplasia
New tissue growth which is unregulated and monoclonal
Define tumors
Abnormal growths of tissue; benign or malignant neoplasm can be implied
Define benign neoplasms
Tumors that remain localized and do not metastasize, but may still produce deleterious effects
Malignant tumors
Referred to as “cancers,” invade locally and have the potential to metastasize.
Two components of neoplasms
Parenchyma and stroma
Define parenchyma
Neoplastic cells; determines biological behavior. Name of tumor is derived from this
Define stroma
The supporting structures including connective tissue and blood vessels. Plays and important role in the growth of the neoplasm
Define differentiation
The extent to which parenchymal tumor cells resemble their normal tissue counterpart
Define anaplasia
“Backward differentiation” - loss of the structural and functional differentiation of the cells from which a neoplasm is derived
Pleomorphism
Variation in the size and shape of cells. Anaplastic neoplasms generally display marked pleomorphism
N:C ratio
Nuclear-to-cytoplasmic ratio - normal cells have 1:4 or 1:6 N:C ratios, but this may approach 1:1 in malignant cells
Define dysplasia
Disorderly architecture and altered cytology of cells, principally found in the epithelium.
Do dysplastic growths penetrate the basement membrane?
NO.
What may be found in dysplastic growths?
Pleomorphism, hyperchromatic nuclei, high N:C ratios, disorderly maturation, mitoses above basal layer
Is dysplasia reversible?
It can be, particularly if factors contributing to this change are removed (e.g., tobacco smoke)
Carcinoma in-situ
When dysplastic cells involve the entire thickness of an epithelial surface
Define metastasis
Secondary implants of a malignant tumor that are discontinuous with the primary tumor and may be in remote tissues
Three pathways of dissemination
Seeding, lymphatics, and blood vessels
Seeding
Within body cavities; seen in ovarian carcinoma
Lymphatic spread
More typical of carcinomas. Initial spread is to regional draining lymph nodes
Hematogenous spread
More typical of sarcomas, but also seen in carcinomas. Cell carcinoma invades nearby veins
