Lecture 8: Neoplasia

Question 1

What at the mechanisms of invasion

Answer 1

1. Impairment of cell adhesion (ex: E-Cadherin inhibition)
2. Basement membrane degradation via proteases
3. Extension into permissive tissue- cleavage of basement membrane proteins generate sites that bind to receptors on tumor cells and stimulate migration

Question 2

Describe the stages of invasion and metastasis

Answer 2

1. Transformed cells must detract from main mass, adhere and penetrate basement membrane and enter ECM
2. Intravasation: extension through endothelium- interacting with lymphoid cells and coating with platelets (form tumor emboli)
3. Extravasation: extension back through endothelium, formation of metastatic deposits and angiogenesis

Question 3

What is the preferred metastatic route for sarcomas

Answer 3

Hematogenous

Question 4

What is the 1st capillary bed the vena cava hits and what tumors is that the most common route for

Answer 4

Vena cava—> 1st capillary bed=lung
Most common route for mammary, skin, soft tissue, bone and thyroid tumors

Question 5

What is the 1st capillary bed for portal vein and what tumors is that the most common metastatic route for

Answer 5

Portal vein—> 1st capillary bed—> liver

Most common route for gastrointestinal and pancreatic tumors

Question 6

What is the most preferred metastatic route for carcinomas

Answer 6

Lymphatics due to large gaps

Question 7

What is the most common route of metastasis for mesotheliomas and reproductive tumors

Answer 7

Transcoelomic exfoliation and implantation

Question 8

What type of tumor is this and what route did it likely use. What is the giant purple clump of cells representative of

Answer 8

Mammary gland Adenocarcinoma with metastasis to lymphatic vessels

Tumor emboli formed- giant clump of purple cells

Question 9

What kind of tumor is this and what metastasis route did it use

Answer 9

Cholangiocellular carcinoma with transcoelomic exfoliation and implantation

Question 10

Where do prostatic carcinomas like to metastasize to

Answer 10

Bone

Question 11

Where do osteosarcomas like to metastasize to

Answer 11

Lung

Question 12

What the primary effects of tumors

Answer 12

1. Loss of function
2. Pain and discomfort

Question 13

What are paraneoplastic syndromes

Answer 13

Symptom complexes that can’t be directly attributed to local or distant tumors

Question 14

What types of tumors is hypercalcemia commonly associated with

Answer 14

1. Lymphoma in dogs (20-40%) and cats
2. Apocrine Adenocarcinoma of anal sac in dogs

Question 15

What are the sources of increased Ca2+

Answer 15

1. Increased Ca2+ reabsorption, decreased phosphate reabsorption: promoted by parathyroid hormone related protein (PTHrP: Adenocarcinoma of anal sac)
2. Release from bones- osteoclasts are stimulated by PTHrP
3. Increased absoprtion in the intestines

Question 16

What type of tumor is this and what is a paraneoplastic syndrome associated with it

Answer 16

Tumor: apocrine Adenocarcinoma of anal sac
Paraneoplastic syndrome: hypercalcemia- PTHrP

Question 17

What is the clinical presentation of anorexia and cachexia as a paraneoplastic syndrome

Answer 17

Anemia, weakness, fatigue, weight loss, weak immune response

Question 18

What are the common mechanisms of anorexia and cachexia as a paraneoplastic syndrome

Answer 18

1. Decreased caloric intake
2. Metabolic alterations: altered sensitivity to insulin, amino acids get directed from protein synthesis or gluconeogensis
3. Increased catabolism: exceeds synthesis of proteins- reduced muscle mass, poor wound healing, low albumin
4. Cytokine release: TNF-alpha encourages lipid breakdown

Question 19

What type of tumor is this and what secondary/ paraneoplastic syndrome can it cause

Answer 19

pituitary adenoma—> increase ACTH—> results in Cushing disease

Question 20

What tissue is this? Describe the appearance and what could have caused this

Answer 20

adrenal gland: cortical hyperplasia
Can be a result of hyperadrenocorticism due to excessive glucocorticoids

Question 21

What is wrong here? What could cause this? What disease is associated with this

Answer 21

skin showing calcinosis cutis (dystrophic calcification). Likely Cushings disease

Question 22

What paraneoplastic syndrome can a pancreatic islet cell tumor cause

Answer 22

Increased insulin production—> leading to hypoglycemia

Question 23

What is the size of a tumor where you can have favorable size, discrete margins

Answer 23

3.0cm or less

Question 24

What is the size if tumor where you have an unfavorable site or infiltrative margins

Answer 24

3 cm or more

Question 25

What surgical margin technique is used here and what kind of tumor

Answer 25

Inking- mast cell tumor

Question 26

What kind of tumor? Monomorphic or pleomorphic? What kind of growth pattern?

Answer 26

Growth pattern: sheets
Monomorphic
Tumor: MCT