03/02b Neoplasia I Flashcards
What is a neoplasm?
An abnormal mass of tissue which exceeds and is uncoordinated with that of the normal tissues, and persists in the same excessive manner after the cessation of the stimuli which evoked the change.
What are the two most important fundamental features of neoplasms?
1) Unregulated growth
2) Clonal genetic defects (derived from single cells, giving rise to new cells)
What is a malignant neoplasm?
A neoplasm that can or has metastasized
What is metastasis?
Spreading to a distant, non-contiguous site
Often lymphatic (nodes), hematogenous (lung, liver, bone, brain), or in body cavities
Fatal if untreated
What are benign neoplasms?
Do not metastasize and generally do not cause the death of the patient
Danger depends on location or possible secretory products
Can malignant neoplasms be cured by surgery alone?
NO, because of their inherent risk of spreading to distant sites
How can you tell if a neoplasm is malignant BEFORE it metastasizes?
Histopathology!
What are the three major histological features that will help distinguish a benign vs. malignant neoplasm?
1) Borders
2) Growth rate
3) Anaplasia
What are the histological characteristics of benign neoplasms?
Encapsulated - pushing borders, but do not invade locally
Slow growth
Mild anaplasia - well-differentiated
What are the histological characteristics of malignant neoplasms?
Local invasion - infiltrative borders, look “stellate” or “spiculated”
Show rapid growth - many mitotic figures
Anaplasia - lack of differentiation
What is anaplasia?
“Lack of differentiation”
Do not resemble tissue of origin, unspecified
What do anaplastic cells look like? Name six features
1) High ratio of nucleus to cytoplasm (N/C ratio)
2) Nuclear hyperchromasia
3) Clumped chromatin
4) Prominent nucleoli
5) Nuclear pleiomorphism - vary in size and shape
6) Frequent and abnormal mitoses
How do you diagnose malignancy? What are the best parameters to use?
Presence of severe anaplasia
Pattern of invasiveness
Metastasis
How are tumors named?
According to the neoplastic component (not the non-neoplastic supportive stromal component)
(Cell type) + (modifier to indicate benign/malignant) + (site of origin)
How are benign tumors named?
Prefix - cell of origin
Suffix - “oma”