What is Neoplasia?
- aka TUMOR or swelling or ONCOS
- persistent abnormal growth of tissue
- exceeds and uncoordinated with growth of surrounding normal tissues
- cells have ability to replicate in absence of growth factor controls
- offspring of new mass of cells have no useful fx
What makes tumors simlar to organs?
- they have parenchyma (fx) and stroma (support)
- they look similar to cells from originating parent organ
- they perform some of fxs that parent organ perform
What makes tumors different from organs?
- Do not contribute to homeostsis
- grow rapidly than surrounding tissue
- some beingn tumors and all malignant tumors never cease to grow
- most tumors show some derangement of histologic architecture
What are the characteristics of a benign tumor?
- BENIGN - --- OMA , adenoma, chondroma "good tumor"
- 1. cell resembes normal cells and tumor architecture resembles that of parent organ
- 2. are usually spherical and compbress surrounding tissue
- 3. grow slowly
- d. never metastasize outside the parent tissue
Are all benign tumors good?
Not necessarily. some can still be very dangerous --> "MALIGNANT BY LOCATION"
- 1. pituitary adenomas - crush normal putuitary gland an optic nerves
- 2. carniopharyngiomas - destroy the hypothalamus
- 3. meningiomas - compress the brain
What are the characteristics of malignant tumors?
- MALIGNANT --carcinomal (epithelial origin) or --sarcoma (mesynchymal) Grow rapidly vs benign
- differ morphologically and functionally
- tumor architecture less organized than parent
- tumors are locally invasive/destructive (grow into surrounding tissue)
- tumor will metastasize to site remote from origin (EXCEPT basal cell carcinoma and gliomas)
- resemblance to parent cells determine tumor's aggresiveness
I-V Tumor gradings (by pathologist)
- grade I = well (similar) differentiated -> normal
- grade II = not so well differntiated
- grade III = worse than grade II --> anaplastic
- grade IV = poor - differentiated --> anaplastic (no recognizability0
- grade V = not differentiated --> anaplastic (no resemblance)
Tumor stages: (by oncologist) based on tumor SPREAD
- Stage I: Tumor is < 1 cm diamter WITHOUT metastases
- Stage II: Tumor is > 1 cm diameter but WITH metastases to REGIONAL lymph nodes
- Stage III: Tumor has infiltrated a deep tissue structure WITH DISTANT metastases
CLINICAL STAGING by TNM system
N- Lymph Nodes
- T (1-3)
- T1 - tumor < 1cm
- T2 - tumor > 1cm
- T3 - tumor invades non-resectable structure
- N (0-2)
- N0 - no tumor in regional lymph nodes
- N1 - tumor is in a nearby lymph node
- N2 - tumor is in a distant/far lymph node
- M (0-1)
- M0 - no distant metastases
- M1 - distant metastases
What is the microscopic appearance and histologic diagnosis of malignancy?
- Big Nucleus (more dna) : less cytoplasm ratio
- wrinkled edges
- Numerous, bizarre mitosis lasting longer than normal tissue
- various sizes of cells w/ loss of orientation to one another
- Possibly a mitotic figure? seen in center of malignant neoplasm
What are the means of Malignant Tumor invasion?
- 1. Local infiltration: intra epithelial spread - early cancers replaced by layer of malignant tumor that DOES NOT PENETRATE Basement Membrane
- eg Carcinoma in situ
- 2. Metastatic spread: transfer of malignant cells from one place to a non connected site.
- -->1st penetrates BM then also through surrounding Extracellular environment
- --> then via Lymphatics (if epithelial origin aka Carcinoma)
- --> then via Blood Vessels (if mesenchymal origin aka Sarcoma)
What are the 3 classes of carcinogenic agents?
- physical agents (e.g. radiation, asbestos...)
- oncogenic viruses
Chemical carcinogen characteristics:
- 1. diverse in structure: synthetic or natural
- 2. derect-relating (no chemical conversion) or Indirect reacting (nee metabolic conversion)
- 3. they are highly reactive electrophils that react with electron rich atoms in DNA - mutagens
- 4. they might need promoters to help express carcinogenicity
What is chemical carcinogenesis the probable result of?
- 1. initiation - irreversible, usually not detectable
- 2. promotion - action of the 2nd agents that without, they have little cancerous acitivity
What are some of the most potent chemical carcinogens that are INDIRECT?
- 1.polycyclic H-carbons - coal, tar origins - eg smoke
- 2. aromatic amines and AZO dyes - aniline dye and rubber industry exposure --> bladder and liver tumors
- 3. nitrosamines - nitrates, food preservatives convert to nitrosamines, blamed for certain liver cancer
- 4. metals - like nickel, chromium, cobalt from occupational setting
- 5. saccharines and cyclamates - artifiicial sweeteners if used in extremely large doses
What are the physical carcinogens?
- 1. Radiation - (uv, xray, radionuclides)
- has mutagenic effects --> chromosome breakage, translocation and point mutations.
- eg SUN
- can be cheimical and physical (inhalation) is associated with malignant mesothelioma
What are the viral etiologies of cancer?
- 1. RNA Retrovirus --> T cell leukemia and lymphoma
- 2. DNA HPV --> carcinoma of the cervix
- 3. DNA Hep B --> Hepatocellular carcinoma
- 4. DNA Epstein-Barr Vbirus --> lymphoma and naso pharyngeal carcinoma
What are some of the symptoms caused by malignant tumors?
- fever (common in Hodgkins)
- hematologic syndromes (
- endocrine syndromes
- neurologic syndromes (SC, and peripheral nerves)
- ---> subacute motor nueropathy lower motor weakness presents without sensory (ALS, etc)
- ---> sensor motor peripheral neuroapthy - distal weakness and sensory loss (dg changes in dorsal root ganglia)