Pathology Neoplasia Flashcards
Explain the significance of glucose 6-phosphate dehydrogenase in determining clonality.
G6PD active isoform ratio is 1:1 in females
- In neoplastic growth, clonality is monoclonal so G6PD ration is disturbed
- In hyperplastic growth, ratio is preserved
What are the characteristics of neoplasia? What differentiates it from dysplasia? Hyperplasia?
Neoplasia: unregulated, irreversible, and monoclonal
- Hyperplasia is polyclonal and reversible
- both dysplasia and neoplasia have mutations but dysplasia is reversible
Clonality of B lymphocytes - light chain phenotype
- Normally light chain kappa to lambda ratio is 3:1
- Ratio is maintained in hyperplastic growth (reactive hyperplasia to infection)
- In neoplastic growth (lymphoma) ratio is disturbed - >6:1 or is inverted (kappa to lambda ratio 1:3)
Reason for lymph node enlargement
- Metastatic cancer
- Lymphoma
- Infection (reactive hyperplasia)
Carcinoma
implies epithelial origin
-generally spread lymphatically; exceptions: RCC- renal vein, HCC-hepatic vein, follicular carcinoma of thyroid, choriocarcinoma
Sarcoma
implies mesenchymal origin
-generally spread hematogenously
Cachexia
weight loss, muscle atrophy, and fatigue that occur in chronic disease (cancer, AIDS, heart failure, TB)
-mediated by TNF-a, IFN-gamma, IL-6
Leading causes of death in adults
- Cardiovascular disease
- cancer
- cerebrovascular disease
Leading causes of death in children
- accidents
- cancer
- congenital abnormalities
Most common cancer by incidence in adults
- Breast/prostate
- lung
- colorectal
Note: squamous cell and basal cell carcinoma very common!
Most common causes of cancer mortality in adults
- lung
- breast/prostate
- colorectal
Screening: Pap smear
: detects cervical squamous cell dysplasia (CIN- cervical intraepithelial neoplasia) before it becomes carcinoma
How many divisions occur before the earliest clinical symptoms of cancer arise?
30 divisions
Screening: mammography
:detect in situ breast cancer before it invades or invasive carcinoma before it becomes clinically palpable
- mammography can detect tumors as small as 1 cm, whereas palable tumors are usually at least 2 cm
Screening: PSA and DRE
:prostate specific antigen and digital rectal exam - detects prostate carcinoma before it spreads
Note:
-BPH usually occurs in the center of the prostate and may surround the urethra so clinical symptoms may appear
-prostate cancer usually occurs in the posterior peripheral zone of the prostate = asymptomatic until very large; DRE to feel posterior prostate
IHC stain- keratin positive cells
epithelium –> carcinoma
IHC Stain- vimentin positive cells
Mesenchyme –> sarcoma
IHC stain- desmin positive cells
muscle —> rhabdomyosarcoma
IHC stain- GFAP positive cells
neuroglia
IHC stain - neurofilament positive cells
neurons
IHC stain- PSA positive cells
prostatic epithelium
IHC stain- ER positive cells
breast epithelium
IHC stain- thyrogloblulin positive cells
thyroid follicular cells
IHC stain- chromogranin positive cells
neuroendocrine cells
IHC stain: S-100 positive cells
melanoma, schwannoma, and langerhans cell histocytosis
Tumor grade
: microscopic assessment of differentiation; how closely do the cells look like the tissue of origin
-usually from 1-4, where 1(low grade) is well differentiated and 4(high grade) is poorly differentiated
Tumor stage
:assessment of size and spread of cancer; based on clinical (c) or pathology (p) findings ex. cT3N1M0
T-tumor size
N- regional nodal involvement
M- distant metastasis; most important prognostic factor
