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”
What is a rhabdomyoma?
Benign neoplasm of skeletal muscle
What is a benign neoplasm of a blood vessel?
Hemangioma
What is an adenoma?
Benign neoplasm derived from glandular epithelium
What is a benign epithelial neoplasm with a cystic or fluid-filled cavity?
Cystadenoma
What is a papilloma?
Benign epithelial neoplasm producing finger-like or papillary projections
What is a carcinoma?
Malignant neoplasm arising from epithelial tissue
What is an adenocarcinoma?
Malignant neoplasm arising from glandular epithelium
What is a malignant neoplasm arising from mesenchymal tissue?
Sarcoma
What is a lymphoma?
Malignant neoplasm arising from lymphoid tissue
What is a malignant neoplasm arising from blood or bone marrow elements?
Leukemia
What are there no really benign tumors of lymphocytes or granulocytes?
Once the lymphocytes proliferate into the bloodstream, they go everywhere (metastasis)
Which four “-omas” are actually malignant?
Lymphoma
Hepatoma
Seminoma
Melanoma
Which three “carcinomas” or “sarcomas” are actually benign?
Basal cell carcinoma (skin)
Cystosarcoma phyllodes (breast)
Well-differentiated liposarcoma (skin)
What is a cancer “grade”?
A histologic parameter quantitating the degree of differentiation of the cancer cells
What is “low-grade” vs. “high-grade”?
Low-grade = well-differentiated, resemble mature normal cells of the tissue of origin High-grade = poorly differentiated, shows little resemblance to tissue of origin
What is the important of grading a tumor?
Grade predicts tumor behavior - frequency of metastasis, response to chemotherapy, etc.
What are the limitations of cancer grading?
Many tumors are of intermediate differentiation
There is sample error with small biopsies
Grading is based on subjective light microscopic interpretation
