b) w/c 13-Jan-14 Tumour/Repro Flashcards
Definition of Neoplasia (3 things)
- Uncontrolled proliferation of cells
- Proliferation continues in absence of the inciting cause
- Neoplastic cells original from a single cell that has undegone mutation
Gross Characteristics of benign tumours
Growth by expansion, low/moderate growth rate, well demarcated from surrounding tissue, smooth, surrounding connective tissue, homogenous cut surface (cystic in glandular)
Microscopic characteristics of benign tumours
Often similar to tissue of origin, well organised, surrounding connective tissue capsule, generally no haemorrhage or necrosis
How do malignant tumours grow?
Growth by invasion of adjacent tissue.
Usually not encapsulated, usually not mobile on palpation.
Difference between haemangioma and haemangiosarcoma?
Haemangioma: Benign tumour of endothelial origin
Haemangiosarcoma: Malignant tumour of endothelial origin
What are benign tumours of epithelial origin known as?
Surface epithelia: Skin- Papilloma
Glandular epithelia: Adenoma
e.g. skin epithial benign: Squamous papilloma
What are malignant tumours of epithelial origin known as?
Malignant tumour of epithelial origin: Carcinoma
Malignant tumour of glandular epithelia: Adenocarcinoma
e.g. mammary adenocarcinoma
What are skeletal muscle tumours known as? (Benign and Malignant)
Both mesenchymal origin
Benign: Rhabdomyoma
Malignant: Rhabdomyosarcoma
What is a Chondrosarcoma?
A mesenchymal malignant tumour of the cartilage (c.f. with chondroma which is BENIGN)
What is the origin of Lymphomas?
Round cell tumours of lymphoid system. Normally malignant therefore should be LYMPHOSARCOMA
What is the ‘proper’ name for Sarcoids?
Low grade fibrosarcomas commonly seen in skin of horses. Caused by bovine papillomavirus infection.
4 types of metastasis
- Lymphatic
- Vascular
- Trans-cavity
- Local
Lymphatic metastasis is typical of _____
Carcinoma. Therefore check drainage lymph nodes
epithelial origin
Vascular metasistasis is typical of _______
Sarcoma
mesenchymal origin
Example of tumour that spreads by trans-cavity metastasis
Mesothelioma (RARE)
Ovarian Carcinoma
Pancrastic Carcinoma
All have close association with omentum. Poor prognosis
How does Fibrosarcoma spread?
Local metastasis therefore reoccur at site of excision
Are mammary adenocarcinomas more metastatic in cats or dogs?
Much more metastatic in cats.Advice unilateral mastectomy as the minimum
Adenocarcinoma= Malignant, Glandular epithelium
How does immunohistochemistry help in tumour diagnosis?
Some poorly differentiated tumours cannon be identifed on morphological grounds alone.
Immunohistochemistry for intermediate filaments or cell surface markets assist identification.
Cytokeratin- epithelial marker for carcinom
Which immunohistochemistry market can be used to help identify a sarcoma tumour?
Mesenchymal market Vimentin
How are t and b cell lymphomas differentiated? Why would be want to do this?
Different prognosis depending on type.
T cell marker is CD3
B cell marker is CD79a
When does tumour grading by immunohistochemistry become more difficult?
As tumour becomes more poorly differentiated (high grade) they loose expression of expected tissue markers.
e.g. Cytokeratin (carcinoma), Vimentin (Sarcoma)
Normally necrotic and cavitated areas should not be sent off to the pathologist. The exception is___
Bone tumours where a sample from the area of maximal bone lysis is most helpful e.g. osteosarcoma or osteoma (mesenchymal origin)
When fixing specimens for delivery, it is important to:
Not put more than 2 cm in (not adequately fixed)
Neutral buffered formalin
Indelible labels
Which type of neoplasm is chemotherapy indicated for?
Disseminated disease e.g. Lymphoma. If removal possible = surgery
What is adjuvant therapy?
Following removal of a tumour e.g. splenic haemangiosarcoma or amputation of osteosarcoma then chemotherapy is given to slow growth of metastatic disease (used for highly malignant tumours)
LET WOUND HEAL FIRST!! DIVING WOUND CELLS
What is neo-adjuvant therapy?
To shrink size of tumour prior to surgery
Why are cytotoxic drugs most useful in the early stages of disease?
Most chemotherapy drugs work when tumour cells are diving most rapidly i.e. start of disease.
The cell kill hypothesis states that tumour cells follow ___ kinetics
First order kinetics i.e. a given dose of cytotoxic drug will kill a fixed percentage of the tumour population e.g. 90% of population
Why is the maximum tolerated dose stated in mg/m2?
Maximum tolerated dose tends to correlate better with body surface area rather than body weight.
Animals <10kg = dose at mg/kg basis
What is metronomic chemotherapy?
Continuous low dose of cytotoxic drug given combined with a NSAID.
Slow growth by inhibiting angiogenesis and immunomoduatory effects (decreasing circulating T-cells)
Will not remove tumour but will slow growth/ stable disease
Which tumours are a) resistant to chemo b) susceptible to chemo?
Relatively resistant: Pancrreatic/Renal carcinomo
Sensitive: Lymphoma
What is the significant of P-glycoprotein (Pgp) in anti-cancer therapy?
MDR1 gene (multi drug resistant gene) leads to increased Pgp expression which pumps cytotoxic drugs out of the cell This MDR1 gene can be activated by glucocorticoids
Which normal body systems are most affected by anti-cancer therapy?
Systems which have rapidly dividing cells e.g. Bone marrow (Myelosuppression), Gastrointestinal toxicity, Hair growth
Significance of Drug extravasation in anti-cancer therapy
Many of IV chemotherapy drugs are irritant if extravated e.g. vincristine, vinblastine, doxorubicin)
Always use catheter and use saline to check patency of vein
What are the effects of myelosuppression on the haemtopoietic system?
Neutropenia, Thrombocytopenia
Neutropenia is the dose limiting effect of many agents.
For neutrophil count drops below 1 x 109 Give prophylactic antibiotics e.g. TMS
When does neutrophil nadir normally occur?
nadir= low point. i.e. most likely point to get infection
Neutrophil nadir normally occurs 7days post treatment
What does platelet nadir normally occur
Maximum thrombocytopenia normally occurs 10 days post treatment
If extravastion occurs, what emergency treatment can you do?
Aspirate as much as possible away from site
For VINCRISTINE: Heat (vasodilation) + Hyaluronidase
For DOXORUBICIN: Ice (vasoconstriction)
Which chemotherapy drug should be avoided in animals with heart disease?
Doxorubicin can cause dysrhythmias during administration. Give SLOWLY.
Mast cell degranulation can occur during administration (urticaria, pruitis, shock etc due to histamine release)
Nephorotoxicity recorded in cats
What side effect does Cyclophosphamide have in dogs?
Haemorrhagic cystitis. Irritant to the to bladder lining
Can give furosamide at the same time to increase excretion time
Which chemo-therapy drug can cause ileus/constipation in the cat?
Vincristine
Which chemotherapy drug should NEVER be used in cats?
Cisplatin (causes fatal pulmonary oedema)
Mechanism of action for:
a) Vincristine
b) Doxorubicin
c) Cyclophosphamide
VINCRISTINE: Mitotic spindle inhibitor. CC specific
DOXORUBICIN: Prevent DNA and RNA synthesis. not CC specific
CYCLOPHOSPHAMIDE: alkylating agent, break DNA strand. Not CC specific
Is mammary neoplasia more common in cats or dogs?
More common in DOGS.
But when it does occur in CATS, 90% are MALIGNANT!!
What is the significance of oestrogen and progesterone receptors on malignant mammary tumours?
(feline tumours normally only progesterone receptors)
Can be used for immunohistochemistry (but not used in vet medicine)
More receptors = good prognosis as well differentiated
How does the relative risk of developing a mammary tumour change depending on time of spaying in DOGS?
and in CATS?
If spayed before first season: 0.05%
After first season: 8%
After second season: 26%
Less protective in cats. before 6 months 9%. >1 yr = no protective effect
Why would a rectal examination be useful after finding a mammary tumour?
Rectal exam may reveal enlarged sublumber lymph nodes
Which type of mammary tumour is the most aggressive and has a very poor prognosis (<30days)
Inflammatory carcinoma. (Incisional biopsy)
Don’t try operating.
Not always clear that it is a mass, more of a diffuse swelling; massive oedema, erythema, pain.
BIOPSY
Antimicrobial of choice for mastitis?
Broad spectrum, time-dependent bactericidal CEPHALOSPORIN.
Likely bacteria: E-coli
What is Galactostasis?
Accumulation and stasis of milk within mammary gland.
Warm, firm, swollen, painful but secretions NOT infected (c.f. mastitis)
Self resolving
Lactation that is not associated with pregnancy and parturition i.e. during a false pregnancy is known as
Galactorrhea
(due to increased prolactin secretion, stimulated by falling progesterone)
Doesn’t require treatment
In cats 2-4 weeks after oestrus, rapid growth of mammary tumour could be:
Mammary neoplasm, but given that it is close to oestrous probably mammary hyperplasia.
Benign condition that resolves once progesterone levels decline. Neutering prevents reoccurrence
Mastitis can be confused with what very serious neoplasm?
Inflammatory carcinoma (prognosis <30 days)
Blood suppy with the mammary glands
Cranial and Caudal ligate epigastric. Branches off internal thoracic
LN drainage of the lymph nodes
4,5 drain to inguinal LN
1,2 drain to axillary LN
3 can drain in either direction, normally to axillary
What is the normal skin margin when excising a tumour (excisional)
2-3cm.
Excise underlying abdominal wall fascia if tumour is attached to it.
Ligate branches of epigastric if encountered
Minimum recommended treatment for a) dog b) cat with mammary tumour
Cats: Unilateral mastectomy
Dogs: Excise all tumour using simplest surgery
Possibly complication of performing a regional mastectomy of the caudal two mammary glands?
Often excised together with inguinal LN. Could cause hind limb oedema (self-correcting by collateral drainage)
Ligate caudal epigastric artery
How do the prognostic factors vary between sarcomas and carcinomas in DOGS?
Sarcomas= worse prognosis
3cm 85% reoccurance (ACT QUICKLY!)
Poorly differentiated 90% mortality at 2 yr
How does the mammary tumour size in CATS determine prognosis?
> 3cm median survival <2cm: 3 yrs
Which factors are NOT PROGNOSTIC in mammary neoplasm?
Site of tumour, type of surgery in dogs, number of tumours, performing OHE at time
How long does it take to alter the BCS by 1.0?
BCS change by 1.0 in 6 weeks
When does a distance examination of a bull for a fertility visit, straight legs could indicate…
Potential problem with with joints in later life/.
Probably fine if only needs to service 1 or 2 cows.
If needs to service 10+ then BAD
What should the circumference of a bull/ram scrotum be?
Bull and Ram should both be 34cm
if 32cm - okay depending on how many needs to service.
Rams: Seasonal breeders (measure at breeding time)
Which parts of the epididymus are palpable?
Head of epididymis is not normally palpable unless diseases
Tail of epididymis is normally palpable
What should the normal testicular tone be in the breeding season?
Flexed bicep tone
What is broken penis and what is the prognosis?
Broken penis is haemtoma in the area of the sigmoid flexure.
Very poor prognosis
