Pathology: Neoplasia Flashcards
Mixed tumors
Tumors that are monoclonal develop into widely varying cell types (i.e. teeth and hair). Pleomorphic.
Teratomas
Tumors that contain tissue from more than one germ cell layer. These often come from totipotent cells
Benign tumor differentiation
Neoplastic cells are well-differentiated and closely resemble the surrounding parenchyma
Why are malignant tumors more difficult to diagnose pathologically than benign tumors?
Malignant neoplastic cells vary greatly in differentiation and anaplasia.
Hallmarks of malignancy
Anaplastic neoplasms, hyperchromatic nucleus, mitoses (abnormal cell divisions), loss of polarity, ischemic necrosis and giant cells.
*What do you see?
Benign, well differentiated tumor in the uterus

*What do you see?
Anaplastic tumor. Note pleomorphism, hyperchromatic nuclei and giant tumor cells

*What do you see?
Anaplastic tumor. Note abnormal tripolar spindle in center cell.

What often occurs in metaplastic epithelial tissue?
Dysplasia = loss of uniformity of individual cell and architecture
When is a carcinoma considered to be invasive?
Once it breaches the basement membrane. Before that, it is an in situ carcinoma

What clinical aspect of neoplasia makes detection difficult?
By the time you find a solid tumor most of its cells are no longer in the replicative pool.
What determines the rate at which a tumor grows?
Doubling time, growth fraction (number of cells in replicative pool) and rate of cell death
Where do most tumor cells go when they leave the replicative pool?
G0 phase
What ultimately determines how fast a tumor grows.
Cell production and cell loss ratio
Why does radiation or surgery normally precede chemotherapy?
Chemotherapy drugs are effective against drugs in the cell cycle. Since many cells in the tumor are in G0, radiation and surgery debulk the tumor to try and get the cells back into replication phase.
What physiological factors can increase or decrease tumor growth over time?
Hormonal stimulation or blood supply
Why are malignant stem cells generally non responsive to current therapies?
Stem cells have a low level of cell division and express drug resistant factors.
*What do you see?
Benign breast tumor. Note connective tissue border that prevents to tumor from spreading into surrounding tissues.

*What do you see?
Malignant breast tumor. Note invasion of breast stroma, absence of capsule, fat in nests and cords of tumor cells

What are the two most reliable features that differentiate a malignant tumor from a benign tumor?
- Metastasis 2. Invasiveness
What malignant tumors do not usually metastasize?
Gliomas (glial cells in the CNS)
What three ways does cancer normally spread?
Seeding, lymphatic spread and hematogenous spread.
Where does seeding most often occur?
Peritoneal cavity
What is the most common mode of cancer spread?
Lymphatics



