Neoplasia Flashcards
Neoplasm
An abnormal mass of tissue, whose uncoordinated and excessive growth exceeds that of normal tissues and persists after the cessation of the initial stimulus.
Are tumors autonomous?
Yes, but they depend on the host for nutrition.
Characteristics of Benign Tumors
Cohesive, slow/limited growth, well circumscribed, lobulated, encapsulated, mobile.
How can benign tumors be lethal?
If they’re in very sensitive areas like the heart (atrial myxoma) or the brain (meningioma).
Characteristics of malignant tumors
Aggressive and limitless growth, invasion/destruction of adjacent structures, poorly demarcated. Infiltrating borders.
How are neoplasms named?
Named for the tissue they are becoming, or for the tissue from which they are derived.
Leiomyoma, and cancerous equivalent
Smooth muscle benign tumor. Leiomyosarcoma.
Adenoma and cancerous equivalent
Glandular epithelium benign tumor, adenocarcinoma.
Hamartoma
Disorganized growth of indigenous tissue. Ex: disorganized bile ducts in the liver
Choristoma
Normal architecture in the wrong location, happens during development. Ex: heterotopic pancreas in the stomach.
Parenchyma vs Stroma
P: The tumor. S: supporting cells and connective tissue.
Hyperplasia
Increase in the number of cells.
Metaplasia
Replacement of one mature cell type with another. Ex: Columnar to squamous in the lungs of smokers.
Dysplasia
Loss of cell uniformity and orientation. Generally with epithelium, where the cells grow in number. First sign on way to malignant neoplasm.
Desmoplasia
A collagenous fibrosis reaction to invasion.
Anaplasia
Complete lack of differentiation. Certainly a malignancy.
Grading of Neoplasms
Assigning a level of differentiation. Grade predicts future behavior.
Criteria for determining grade
Uniformity, nuclei, mitoses, architecture
What is abnormal about cancer cell nuclei?
They are enlarged and elongated, hyperchromatic, increased nucleus to cytoplasm ratio. Prominent nucleoli.
What is abnormal about cancer cell uniformity?
Pleomorphism: large variation in size and shape.
What is abnormal about cancer cell mitoses?
Higher number relative to healthy cells. Atypical shapes of mitotic cells. Sometimes tripolar.
What is abnormal about cancer cell architecture?
Loss of polarity and luminar orientation.
Clinically detectable rate of tumor growth vs rate that’s incompatible with life
10^9 (30 doublings) vs 10^12 (40 doublings)
Rate of tumor growth dependent on…
Doubling time, growth fraction (% of neoplastic cells dividing), rate of cell loss. Growth fraction most important.
Susceptibility to chemotherapy determined by…
Growth Fraction.
How does surgery affect growth fraction?
Increases it! Increasing susceptibility to chemo.
What is easier to resect, benign or malignant growth?
Benign, good borders. Malignant tumors have terrible borders and cause a desmoplastic response if they have infiltrated surrounding tissue, increasing collagen and fibrous tissue.
Carcinoma in situ
Dysplasia that involves that entire thickness of epithelium. Seen generally in the cervix, the thin squamous cells at the top are replaced by rounded cells all the way through.
Metastasis
Remote tumor deposits, a keystone feature of malignant tumors. Correlates with tumor grade
3 means of metastasis
Lymphatic spread- carcinomas spread through regional lymph nodes. Hematogenous spread- through vessels, generally to liver and lungs. By both carcinomas and sarcomas. Seeding of cavities- pleura and peritoneum, carcinomas.
Tumor Staging
T (Size of primary tumor, 0-4), N (number/location of regional nodes), M (metastases, number sites). More important for prognosis than grading.
Paraneoplastic syndrome
A comorbidity of cancer, unrelated to the tumor’s location.
Trousseau Syndrome
Causes venous thrombosis and a hypercoagulable state. Found with cancers like pancreatic carcinoma.
What tumor suppressor is lost leading to polyp formation?
APC
When is p53 lost? What is the consequence?
Usually late stage, causes development of full blown carcinoma.
Things associated with invasion and metastasis
Loss of cadherins, ecm degradation by metalloproteases, increased attachment and migration, angiogenesis.
Causes of skin cancer:
UVB exposure causes pyrimidine dimers.
Cause of melanoma vs non-melanoma skin cancer
Intensity of light in melanoma, total exposure in non-melanoma.
Cervical Squamous Cell Carcinoma caused by…?
HPV
Cribiform
A gland within a gland
