Exam 3 (Lecture 17) - Neoplasia 1 Flashcards
What is oncology?
The clinical field of studying neoplasms.
What is a neoplasm?
“New growth”
An ABNORMAL MASS of tissue, the growth of which is uncoordinated with that of the normal tissues and persists in an excessive manner after the cessation of the stimuli which evoked the change.
What is a tumor?
“A swelling”
What is a benign neoplasia?
1) A neoplasm that’s unlikely to cause harm
2) DOES NOT invade surrounding tissue
3) DOES NOT spread to other anatomic locations
What are the key features of neoplasia?
1) Excessive growth (vs. hyperplasia)
2) Lack of responsiveness to normal growth controls
3) Independent of causal stimulus
4) Heritable from cell to cell (mutation)
What is neoplastic transformation?
The process whereby a cell becomes neoplastic = “transformed” cell.
- Becomes autonomous
- Not subject to normal growth controls
- Free of normal structural and functional constraints (however; may outgrow its blood supply)
What are preneoplastic changes?
Changes preceding tumor emergence.
Tumor development is a step-wise process; increases the likelihood for progression to neoplasia in the affected tissue.
What is a malignant neoplasia?
1) A neoplasm LIKELY to cause harm
2) INVADES locally
3) SPREADS by metastasis (“change of places”)
- THE TERM CANCER ALWAYS MEANS MALIGNANT!!!!
What does cancer mean?
Malignant neoplasm
What is a carcinoma?
Neoplasm of epithelial origin; malignant
What is a sarcoma?
Neoplasm of mesenchymal origin; malignant
What is metastasis?
Distant spread of neoplasm (AKA “mets”)
- Primary site
- Secondary site = metastasis
What are mesenchymal tumors?
1) Tumors that arise from cells of embryonic mesodermal origin.
2) These tumors are generally composed of spindle cells arranged in streams and bundles or round cells arranged in solid sheets.
3) Benign tumors originating from mesenchymal cells are usually named by adding the suffix -oma to the name of the cell of origin.
- Ex: Fibroma = A benign tumor of fibroblast origin
What are hematopoietic tumors?
1) Round cells of the hematopoietic system (cells in bone marrow and blood vessels); also mesenchymal.
2) Tumors arising from these cells are called sarcomas.
- Ex: Lymphosarcoma = A malignant tumor of lymphocytes
3) Malignancies arising from circulating blood cells or their precursors are termed leukemias (“white blood”)
What are epithelial tumors?
1) Tumors that arise from all three germ layers (endoderm, mesoderm, and ectoderm).
2) The terms adenoma, papilloma, and polyp refer to benign epithelial tumors.
3) Adenoma =Denotes either a tumor arising from glandular epithelium with characteristic acini and duct (benign).
4) ALL malignant tumors of epithelial origin are termed carcinomas (“cancers”).
What are the tumor types?
1) Mass
2) Neoplastic
What are the types of mass tumors?
1) Abscess
2) Granuloma
3) Hyperplasia
What are the types of neoplastic tumors?
1) Round Cell
- Lymphoma
- Mast cell tumors
- Plasma cell tumors
2) Epithelial
- Adenoma
- Carcinoma
3) Mesenchymal
- “bump” -oma
- Sarcoma
What is a hamartoma?
Disorganized, mature tissue in a normal anatomic location.
What is a choristoma?
Normal, mature tissue at an ectopic site.
- Ex: Dermoid
What are benign and malignant tumors of connective tissue/fibroblasts called?
Benign = fibroma
Malignant = fibrosarcoma
What are benign and malignant tumors of fat/adipocytes called?
Benign = lipoma
Malignant = liposarcoma
What are benign and malignant tumors of cartilage/chondrocytes called?
Benign = chondroma
Malignant = chondrosarcoma
What are benign and malignant tumors of bone/osteoblasts called?
Benign = osteoma
Malignant = osteosarcoma
What are benign and malignant tumors of blood vessels/vascular endothelium called?
Benign = hemangioma
Malignant = hemangiosarcoma
What are benign and malignant tumors of lymphatic vessels/lymphatic endothelium called?
Benign = lymphangioma
Malignant = lymphangiosarcoma
What are benign and malignant tumors of synovium/synovial lining cells called?
Benign = synovial myxoma
Malignant = synovial histiocytic sarcoma
What are benign and malignant tumors of mesothelium/mesothelial cells called?
Benign = ?
Malignant = mesothelioma
What are benign and malignant tumors of meninges/meningeal lining cells called?
Benign = meningioma
Malignant = malignant meningioma
What are benign and malignant tumors of ovary/modified mesothelium called?
Benign = adenoma
Malignant = adenocarcinoma
Describe benign tumors.
Often encapsulated (separated from normal tissues by fibrous connective tissue).
Generally grow in an expansile way, compressing adjacent tissue.
Describe malignant tumors.
Often unencapsulated or grow through the tumor capsule.
Invading or infiltrating the surrounding tissues as they grow.
Alterations in cell adhesion, motility, and protease production allow tumor cells to leave the tumor mass and
penetrate surrounding tissue.
Must become completely independent of local growth regulatory controls and acquire an independent blood supply to invade tissues and ultimately metastasize.
How is tumor behavior assessed?
Cytologic, gross, and microscopic features.
Cytology = Criteria of malignancy
Histology = Is there presence of lymphatics? Is the tumor well demarcated or invasive?
Morphologic diagnosis for tumors:
Organ: Cell of origin, benign/malignant, metastatic (?)
Ex in oral cavity: Squamous cell carcinoma
Describe the gross appearance of neoplasms in regards to color.
The color can resemble that of the parent tissue.
Can also be:
- Black = melanocytic origin
- Dark red = hemorrhage; highly vascular
- Pale = new growth; necrosis; calcification
Describe the consistency of neoplasms.
Connective tissue = Firm
- EXCEPT myxoma/myxosarcoma
Bone = Hard
Edema = Soft
Friable = Reduced blood supply
What is the two stage theory of carcinogenesis?
1) Initiators likely cause mutations of specific genes
2) Promoters often act by causing proliferation or selection of transformed clones
*Some chemicals are “complete carcinogens” (ie cause the mutations/proliferation)
Is initiation genetic? Is it reversible?
Genetic; irreversible
Is promotion genetic? Is it reversible?
Nongenetic; reversible
Is progression genetic? Is it reversible?
Can be either; can also be either; depends on situation
What is latency in regard to tumor growth?
The time before a tumor is clinically detectable.
- Smallest detectable mass is 1 cm diameter (about 109 cells)
- Once they’re clinically detectable, they only need 10 subsequent doubling cycles are required to convert
a 1g tumor into a 1kg tumor.
What is proliferation in regard to tumor growth?
Failure to enter the G0 (non replicative) phase of the cell cycle.
Failure of arrest at checkpoints in the cell cycle.
