Neoplasia Part 1 Flashcards
What is a neoplasia? Neoplasm? Oncology?
- Neoplasia-> The process of tumor formation.
- Neoplasm: “New growth” - “composed of cells originally derived from normal tissues that have undergone heritable genetic changes that allows them to become unresponsive to normal growth controls and expand beyond their normal anatomic boundary”
- Oncology: Study of tumors or neoplasms.
What are the components of neoplasms? What effects the stroma and how?
Components of Neoplasms:
• Paranchyma
• Stroma ( connective tissue/ blood vessels that support the neoplasticism cells. Some tumors induce desmoplasia (development of collagen- rich fiberous connective tissue stroma))
- Some things tumor produces will effect the stroma and vice versa. Cytokines in stroma can modify biological effects/ response of tumor.
• Breast cancer can cause a lot of desmoplasia ( tumor may be very hard, a lot of fibrosis) malignant epithelial tumor indication sometimes
What are the preneoplastic changes? Why is mitotic division very important to the neoplasticity of a cell? What happens if you take out the inciting agent that induce the preneoplastic change?
Preneoplastic changes:
Hyperplasia, metaplasia, dysplasia
Hypertrophy can be considered preneoplastic change.
• Mitotic division is very important to the neoplasticity of a cell. If the cell is rapidly dividing, their is more chance of DNA damage and if they are allowed to replicate, eventually they can aquire the ability to proliferate outside the growth capacity.
If you can take out inciting agent that is inducing this preneoplastic changes than things should be fine, but it is not always.
What is hyperplasia? What can occur in a mammary gland? What does insitu mean? What should you do if you have a neoplasm in situ?
Hyperplasia: excess of cell growth.
Normal mammary duct-> hormonal changes can cause intraductal hyperplasia-> which will with chronigincity cause intraductural hyperplasia with atypical-> later it can become intraductal carcinoma in situ -> invasive ductal cancer
In situ- means still confined to basement membrane and has not infiltrated adjacent tissues.
• If you do something right away, there is a high chance you can prevent worsening.
What is metaplasia? What is the tissue usually changed to?
- metaplasia -> reversible change in which one adult cell type is replaced by another of the same germ line. Usually specialized epithelium is replaced by less specialized epithelium.
- Metaplasia is often but not always an adaptive response.
What occurs with a carcinoma in situ?
- entire thickness of the epithelium is replaced by dysplastic cells.
- This occurs a lot in cats.
- Cats will develop dermal keratosis from sunbathing, chronic irritation of the skin with dysplasia. The layers of epidermis becomes a bunch of disorganized cell, and eventually can become squamous cell carcinoma.
- White cats/ white areas more prone.
What are the malignant and benign tumors of each of these Mesenchymal tissues?
- Fat
- Fibrous connective tissue
- Cartilage
- Bone
- Blood vessel
- Lymphatic Vessel
- Synovium
- Mesothelium
- Meninges
- Ovary
- Lymphoid tissue
- Bone marrow
- Connective tissue
- Smooth Muscle
- Skeletal Muscle
What are the names of the malignant and benign tumors of epithelial origin?
- Squamous epithelial cell
- Adenexal cells
- Melanocyte
- Transitional epithelium
- Uterine columnar epithelium
- Lining of glands/ ducts
- Hepatocyte
- Renal tubular cell
- sertoli cell
- germ cell ( testicle)
- stromal cell ( ovary)
- Germ cell (ovary)
What are the names of malignant and benign tumors of nervous tissue?
- astrocyte
- oligodendrocyte
- microglial
- schwann cell
- Neural cells (PNS)
- Neural Cells (CNS)
What are the names of mixed tumors of the mammary gland, testicle, and ovary?
What are the diffences between benign and malignant tumors in the following categories?
- Differentiation
- Growth rate
- Local invasion
- Metastisis
Differentiation
Benign: Well differentiated morphologic features and function. Structure similar to tissue of origin, little or no anaplasia.
Malignant: Poorly differentiated, morphologic features and function. Tissue of origin sometimes unclear. Variable degrees of anaplasia
Growth Rate
Benign: Slow, progressive, expansion, rare mitotic figures, notmal mitotic figures, little necrosis.
Malignant: Rapid growth, frequent mitotic figures, abnormal mitotic figures, necrosis if poor blood supply.
Local Invasion
Benign: No invasion, cohesisve and expansile growth. Capsule often present
Malignant: Local infiltrative growth, capsule often absent or incomplete
Metastisis
Benign: No metastisis
Malignant: Metastasis sometimes present.
What are undifferentiated tumors?
- undifferentiated tumors
- Mixed tumors (multiple cell types derived from a single or multiple germ cell layer - pluripotential or totipotential.
What are teratomas? Is it a mixed tumor? Where can they be seen? Are they benign or malignant?
• Teratomas - usually in horses/ young animals
◦ Usually is incidental finding.
◦ You can find teeth, hair, cartilage ect in this mass within the testicle. They arise from totipotent germ cells.
◦ Occasionally you can find it in the ovaries of mares.
What is a nephroblastoma? Is it a mixed tumor?
Where can they be seen? Are they benign or malignant?
Nephroblastoma - more common renal tumor in pigs.
Benign tumor
• usually found in younger animals, normally in the slaughter house this is found.
• Mixed tumor because it has an epithelial component that form tubules, which give the appearance of fronds and look like primitive glomeruli.
• You can see nephroblastomas also in children.
• Can also be seen in chickens
These tumors arrise from totipotent cells.
Can also be considered mixed types
• German Shepard may develop tumor in the thoracolumbar area in spinal cord and they are thinking it is a nephroblastoma.
• Present with neuro signs, ataxia, ect.
What is the biology of tumor growth, benign vs. malignant?
a) Differentiation/ anaplasia b) Rate of growth c) Local invasion ( expansile / infiltrative growth) d) Presence or absence of metastasis
A.) differentiation/ anaplasia: benign tumors are usually well differentiated , and you can tell cell of origin. Malignant normally are anaplastic and its usually undifferentiated)
B.) Rate of growth- Slow growth (usually benign)
• rapid growth ( usually rapid growth)
C.) local invasion (expansile/ infiltration growth)
• benign tumors grow by expansion ( producing compression of adjacent tissue) Malignant tumors are infiltrative growth. They grow into the tissue. Hard to get good margins some time)
D.) Presence or absence of metastasis
• 2 degree growth, benign never Mets, malignant Mets.
What is differentiattion/ anaplasia?
a) Differentiation/ Anaplasia
“ Refers to the extend to which parenchymal cells resemble the correspondent normal parenchymal cells, both morphologically & functionally
“ Benign tumors are well -differentiated
“ Malignant neoplasms can be well - differentiated or undifferentiated (the latter are said to be “anaplastic”).
What is anaplasia usually characterized by?
- pleomorphism- different shape
- abnormal nuclear morphology
- high mitotic rate
- loss polarity (disorganization)
Does anaplasia represent reverse differentiation of mature normal cells?
The truth is that in most cancers anaplasia does not represent reverse differentiation of mature normal cells; anaplastic cells arise from less differentiated stem cell- like (totipotent cells) present in tissues.
What is this black arrow indicating about the cells of this muscle tissue?
- Pleomorphic- varying shapes
- Black arrow shows rhabdomyosarcoma,
- nuclei of some cells very large, variation of cytoplasm quantity, ect.
What are the main mechanisms that regulate tissue growth? What cells are not very mitotic? Which are highly mitotic?
- Rate of cell proliferation (fraction of cells in the replicative pool !cells undergoing mitotic activity)
- Rate of programed cell death (apoptosis)
- hemapoeitic tissues are highly mitotic, as well as gastric mucosa, so important to remember.
- cardiac and nervous tissue dont replicate (heart and cns dont change after birth, you got what you got)
- Mutation in important gene can lead to neoplasm.
What are permenant, quiescent/ stable, continous/ cycling labile cells?
- Permenant: no longer replication/ regenerating
- Quiescent stable cells: sometomes regeneration
- Continious cycling labile cells -> consistently regenerating/ replaced
• there are checkpoints at various segments of mitosis.
Is this tumor benign or malignant? What are some identifiers/ characteristics that let you know what it is?
• Proliferative lesion, no exudate, well demarcated, likely be benign ( solid tissue, likely tumor)
What is seen in this image? What are its characteristics? Is it benign or malignant?
- proliferative lesion in mammary gland,
- malignant, ulceration and necrosis, not typical for benign.
- most benign tissues are mobile, malignant tumors are usually well attached
What is seen in this section of mammary tissue?
- Abnormal: cells are anaplastic, they have degree pleomorphism, cell nuclei enlarged, ect.
- 90% mammary tumors in cats are malignant : mammary carcinomas
- Not the case in dogs
What is occuring in this image? What is the way its appearing called? What could occur as a potential side effect or issue with this kind of neoplasm?
- Benign tumor: lipoma, common in mesentary of most horses.
- Usually pedunculated, doesnt produce any clinical problems, but dependent on location it can change if it results in clinical sings/ death.
- If lipoma twists around the peduncle, it could cause ischemic damage or necrosis of the lipoma, and this could cause issues.
- If the lipoma is large enough/ the peduncle has enough give it is possible that the peduncle may wrap around intestines and can cause volvulus.
What is seen in this image? Is it malignant or benign?
Pituitary tumor, but is benign, clearly demarcated ( round), but since location is in brain it will cause significant issues.
What is occuring in this image? Is it common? Is it benign?
- Common in dogs and cats: meningiomas, benign, well confined, proliferative lesion,
- No such thing as benign tumor in brain, due to compression it will always be problematic, just depends on growth rate prognosis.
What is the main issue with meningiomas and the damage they cause?
you can see there is no infiltration but significant compression.
• Tumor causing compression of brain/ brain stem, act quickly
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What is the idea of how cells can become malignant?
- One particular cell may undergo a bunch of alterations to allow it to become malignant
- specific clones of cells.
- Successful clones- high proliferation and decreased immune response.
- When they are successful they can metastisize.
What is seen in this subsection of feline mammary tissue?
- section of skin in mammary area. Purple/ blue areas of hypercellularity is seen. This indicates neoplasia, since they are not clearly demarcated/ boundries are blurred it is likely malignant.
- Malignant tumor of epithelial origin -> carcinoma
The image on the left is an image of the lymph node of the cat that the subsection of mammary tissue is from? Wjat can be seen with the blue arrow?
- Sample of regional lymph node was taken as well to look for metastasis.
- Arrow points to areas of lymphatic metastisis.
- 90% of tumors in cats are malignant
What is gastric carcinoma? What can be seen in tumors of this kind? Where do these tumors arise from, who is it common in? What tissue is involved in this? Ect?
- Large animals also get tumors.
- Gastric carcinoma: arrises from esophageal region of gastric mucosa. It is not uncommon in horses.
- This area is lined with stratified squamous epithelium. (Squamous cell carcinoma) Causes ulcerations, proliferatice lesions, ect)
- Infiltrative to tissue so areas of this stomach would be thickened.
What can be seen in this image?
• Peritoneal carcinomatosis ( peritoneal spreading )
What is evident in this section of gastric tissue? What is circled by this red circle?
- these areas of blue are mucous secreting neoplastic epithelial cells, characterized by bluish foamy cytoplasm, infiltrate the muscle layer of the stomach.
- The morphology is similar to goblet cells. These are the cells that became neoplastic, which infiltrated the wall of the stomach.
- This is mucinous gastric carcinoma.
In this image, is there transcoelmic spread?
yes this is transcoelimic spread ( peritoneal implantation)
Is there transcoelimic spread in this image?
- Peritoneal implantation (transcoelomic spreading -> peritoneal carcinomatosis
- Nodules attached to the mesentary.
What is occuring in this image?
• Multifocal tumor - can be primary or metastatic ( that arrised from somewhere else and then eventually made it to the liver tissue). This is a pancreatic carcinoma that spread to liver tissue
What is occuring in this image? Why?
- Umbilicated appearence of the lesion is often suggestive of carcinoma. Umbiliicated = like a naval.
- Tumor is outgrowing its blood supply so there are these central areas of necrosis, which has a crater like or naval appearence.
- There is some sarcomas that ocassionally also look like this.
