Neoplasia Flashcards
What is neoplasia?
-new growth that is NOT under the normal control mechanisms
What is desmoplasia?
=fibrous stroma present in some cancers
What are the two basic components of all tumors (benign or malignant)?
- Neoplastic cells that constitute the tumor parenchyma
- Reactive stroma made up of connective tissue, blood vessels, and variable numbers of cells of the adaptive and innate immune system
What makes a tumor benign?
- gross and microscopic appearances are considered relatively innocent, implying that it will remain localized,
- will not spread to other sites
- is amenable to local surgical removal
What are the general rules for naming a benign tumor?
“root word” + _oma
What is a polyp?
- a tumor that projects into a lumen, usually GI tract
- usually benign
A rhabdomyoma is a:
A. Malignant tumor of smooth muscle
B. Benign tumor of fat
C. Benign tumor of skeletal muscle
D. Malignant tumor of collagen
C. Benign tumor of skeletal muscle
What are the general rules for naming a malignant tumor?
-“Root word” + carcinoma or sarcoma
What is a mixed tumor?
- a divergent differentiation of a single neoplastic clone in a tumor
- contain epithelial components scattered within a myxoid stroma that my contain cartilage or bone
What is a Hamartoma?
- A disorganized by benign-appearing masses composed of cells indigenous to the particular site
e. g. A pulmonary chondroid hamartoma contains islands of disorganized but histologically normal cartilage, bronchi, and vessels
What is a Choristoma?
- A heterotopic rest of cells
- developmental, not a metastasis
e. g. A small nodule of well-developed and normally organized pancreatic substance may be found in the submucosa of the stomach, duodenum, or small intestine
What are the common exceptions to the benign vs cancer naming conventions?
Lymphoma – malignant tumor of lymphoid cells
Hepatoma – malignant liver tumor
Neuroblastoma – malignant tumor of primitive neural tissue
Wilms tumor – malignant renal tumor
Ewing sarcoma – malignant bone tumor
What does differentiaton mean in context of tumors?
How closely the tumor resembles normal tissue
**we do not talk about differentiation in benign tumors
What is anaplasia?
- lack of differentiation in tumors
- so poorly differentiated, we can’t tell what organ it came from
What are the histological characteristics of malignant anaplasia?
Pleomorphism
Hyperchromasia
High nuclear:cytoplasmic (N:C) ratio
Prominent nucleoli
High mitotic rate, abnormal mitotic figures
Tumor giant cells
Loss of normal orientation
What is pleomorphism ?
- variability in size and shape
- range from small to tumor giant cells (variability in size)
**not to be confused with normal giant cells
What is hyperchromatism?
-A lot of DNA chromatin (very dark)
What is a papilloma?
-benign tumor with “finger-like” projections on a surface into a lumen
**don’t confuse with polyp, it is a subclass of polyps
What does Sarcoma mean?
-the tumor is derived from mesenchymal tissues
What does carcinoma mean?
-the tumor is derived from epithelial tissue
What is dysplasia? Is it reversible?
- loss of uniformity of cells, loss of normal architecture
- Usually applied to epithelial surfaces
- dysplasia is reversible, but may be a precursor to malignant transformation
What does Carcinoma in Situ mean?
-dysplastic features involving the whole thickness of the epithelium, but no invasion into deeper tissue
**not actually a carcinoma, malignancy occurs when it invades past the basement membrane
Why do benign tumors usually develop a rim of compressed fibrous tissue called a capsule?
-benign tumors grow and expand slowly
________ unequivocally marks a tumor as malignant.
-metastasis
What increases the likelyhood that a tumor is metastasizing?
- lack of differentiation
- aggressive local invasion
- rapid growth
- Large size
What is hematogenous spread of a cancer?
- metastasis via the blood vasculature
* more common in Sarcomas
Is dysplasia reversible?
Yes
What is the most common abnormality of protooncogenes in human tumors?
- point mutation in the RAS family of genes
* 15-20% of all human malignancies contain mutated versions