Exam 3 - Tumors of the Canine & Feline Mammary Gland

Question 1

how many mammary glands do dogs & cats have?

Answer 1

dogs - 5 pairs

cats - 4 pairs

Question 2

what serves as lymphatic drainage for the mammary glands?

Answer 2

axillary lymph nodes & inguinal/sublumbar lymph nodes

Question 3

T/F: age at the time of spaying has a direct effect on incidence of canine mammary tumors

Answer 3

true

Question 4

incidence of mammary tumors in dogs increases with what?

Answer 4

age of the animal

Question 5

what is the common age of dog that is affected by mammary tumors?

Answer 5

10 years

Question 6

T/F: an intact female dog & a female dog that was spayed after her 2nd estrus have the same risk of developing a malignant mammary tumor

Answer 6

true - both 26%

Question 7

what are some risk factors associated with canine mammary tumors?

Answer 7

larger breed dogs

spaniels, poodles, dachshunds

obesity at 1 year of age

Question 8

what is the rule of 50 for dogs?

Answer 8

50% of mammary tumors are malignant

50% of mammary tumors are benign

50% of the malignant tumors will metastasize

Question 9

most mammary tumors in dogs are what kind?

Answer 9

carcinomas

Question 10

what are some canine mammary tumor types that provide poor histology?

Answer 10

sarcomas - hemangiosarcomas, osetosarcoma, fibrosarcoma

inflammatory carcinomas

ductal carcinomas

anaplastic carcinomas

Question 11

what canine mammary tumor type is associated with edema, bruising, ulceration, and is very painful?

Answer 11

inflammatory carcinomas

Question 12

what is the grading system used for canine mammary tumors?

Answer 12

grade 0 - in situ

grade 1 - lesions that invade the stroma but have no vessel invasion

grade 2 - vascular/lymphatic invasion and/or lymph node metastasis

grade 3 - pathologic evidence of distant metastasis

Question 13

what is tumor grade based on in canine mammary tumors?

Answer 13

histologic differentiation

Question 14

what is the typical patient presentation of mammary masses?

Answer 14

> 50% have multiple masses, and 65-70% of them are in glands 4 & 5

Question 15

what does a benign mammary mass look & feel like?

Answer 15

small, well circumscribed, & firm

Question 16

what does a malignant mammary mass look & feel like?

Answer 16

rapid growth, ill-defined, fixated to underlying tissue or skin, often ulcerated

Question 17

what clinical signs are associated with inflammatory carcinomas?

Answer 17

multiple glands are affected, extends down the limbs or up the body wall, edema, erythematous, ulcerated, very painful, & mastitis is often more localized & seen after estrus

Question 18

what tumor is this?

Answer 18

inflammatory carcinoma

Question 19

what are some components of a good physical exam for a patient presenting with mammary masses?

Answer 19

palpate each & every gland, palpate regional lymph nodes, auscult lungs carefully, rectal exam, abdominal palpation

lameness or flat bone pain

Question 20

what is the gold-standard for diagnosing a malignant mammary tumor? why not FNA?

Answer 20

histopathology is the gold standard

FNA can’t always differentiate between benign & malignant but can rule out non-neoplastic disease

Question 21

what diagnostics & staging should be used in a dog with a mammary mass?

Answer 21

chem, cbc, & ua

chest rads

coagulation panel

FNA tumor

histopath

Question 22

how is staging done in mammary tumors?

Answer 22

evaluate local lymph nodes - FNA & ultrasound

evaluate distant metastasis - ultrasound & thoracic radiographs

basic blood work - paraneoplastic syndromes & liver metastasis

Question 23

when using rads/ct for staging, in regards to tumor size, lymph node metastasis, & distant metastasis, what is the staging of canine mammary cancer?

Answer 23

stage I - <3cm, no mets anywhere

stage II - 3-5cm, no mets anywhere

stage III - >5cm, no mets anywhere

stage IV - any size, lymph node mets

stage V - any size, mets or no mets in lymph nodes & distant mets

Question 24

what are lumpectomies suitable for?

Answer 24

<0.5-1 cm masses - not for fixed tumors

Question 25

what are mammectomies suitable for?

Answer 25

tumors >1cm or larger, fixed tumors, tumors centrally located in the gland, & must remove abdominal wall fascia & skin

Question 26

what are regional mastectomies suitable for?

Answer 26

lymphatic connections between 1, 2, & 3 lymphatic connections between 3, 4, & 5 large tumors, tumors on the border of 2 glands, tumors with known poor histology, & multiple masses

Question 27

T/F: unilateral/bilateral mastectomies are shown to increase survival times in dogs

Answer 27

false

Question 28

what are unilateral/bilateral mastectomies suitable for?

Answer 28

multiple masses found throughout the mammary chains

Question 29

when should lymph node resection be considered in dogs with mammary neoplasia?

Answer 29

only remove the axillary if enlarged inguinal - remove with the 5th gland if enlarged

Question 30

when is chemotherapy utilized for dogs with mammary neoplasia?

Answer 30

doxorubicin, cytoxan, 5-fluorouracil stage IV/V, dogs with lymphatic invasion, & mitotic index > 9

Question 31

what limits radiation therapy in mammary neoplasia in dogs? what can it be used for?

Answer 31

primary location of the cancer is what's limiting palliation of bone pain

Question 32

why is OHE listed under therapy for mammary neoplasia in dogs?

Answer 32

won't change the incidence of mammary neoplasia, but it may prevent other diseases, so SPAY FIRST!!

Question 33

what is the median survival time for a mammary tumor < 3cm?

Answer 33

22 months

Question 34

what is the median survival time for a mammary tumor 3-5 cm?

Answer 34

14 months

Question 35

what is the median survival time for a mammary tumor > 5cm?

Answer 35

10 months

Question 36

what is the median survival time of mammary neoplasia if the animal is positive for lymph node metastasis?

Answer 36

120 days

Question 37

what is the median survival time of mammary neoplasia if the animal is negative for lymph node metastasis?

Answer 37

> 800 days

Question 38

what is the median survival time of mammary neoplasia if the animal is positive for distant metastasis?

Answer 38

2-3 months

Question 39

what is the median survival time of inflammatory carcinoma?

Answer 39

25 days with palliative care - recur within weeks after surgery

Question 40

what is the 3rd most common tumor in the cat?

Answer 40

mammary tumors

Question 41

what cats are predisposed to getting mammary tumors?

Answer 41

10-12 year olds, intact females

Question 42

T/F: exogenous hormones increase risk of feline mammary tumors

Answer 42

true

Question 43

how does early spaying protect a cat from getting mammary tumors?

Answer 43

OHE before 6 months of age - decreases risk by 91% OHE before 1 year of age - decreases risk by 86%

Question 44

what is the rule of 80 for feline mammary tumors?

Answer 44

> 80% are malignant > 80% will metastasize sarcomas & inflammatory carcinomas are rare while squamous cell

Question 45

what condition can look like a tumor, occur in young cats after a silent estrus, or occur in any cat after exogenous progestin administration?

Answer 45

fibroepithelial hyperplasia

Question 46

what condition is seen in this cat?

Answer 46

fibroepithelial hyperplasia

Question 47

what is fibroepithelial hyperplasia?

Answer 47

condition that occurs in young cats after a silent estrus 1 or more glands, often bilateral, can become very large, erythematous, ulcerated, & edematous

Question 48

why do an FNA on a suspected feline mammary tumor?

Answer 48

rule out mastitis or foreign body first - assume it's malignant

Question 49

what should be used for diagnostics & staging in feline mammary tumors?

Answer 49

cbc, chem, ua chest rads, abdominal ultrasound

Question 50

when using rads/ct for staging, in regards to tumor size, lymph node metastasis, & distant metastasis, what is the staging of feline mammary cancer?

Answer 50

stage I - <2cm, no mets anywhere stage II - 2-3cm, no mets anywhere stage III - 0-3cm, regional lymph nodes affected stage IV - any size, mets or no mets in lymph nodes & distant mets

Question 51

what therapy is recommended for feline mammary cancer?

Answer 51

surgery - for invasive tumors with early metastasis staged unilateral mastectomies regardless of tumor size OHE may help - good for fibroepithelial hyperplasia

Question 52

why is chemo used for therapy of feline mammary cancer?

Answer 52

gross disease - short lived response to doxorubicin +/- cyclophosphamide microscopic disease - adjuvant to surgery, overall increase in survival time

Question 53

what is the prognosis of mammary tumors in cats?

Answer 53

guarded to poor in all cats - tumors can recur with conservative surgery

Question 54

what is the median survival time of a feline mammary tumor that is > 3cm?

Answer 54

4-12 months

Question 55

what is the median survival time of a feline mammary tumor that is 2-3 cm?

Answer 55

15-24 months

Question 56

what is the median survival time of a feline mammary tumor that is < 3cm?

Answer 56

~ 3 years

Question 57

what is the median survival time of feline mammary cancer using a staged bilateral mastectomy?

Answer 57

> 900 days

Question 58

what is the median survival time of feline mammary cancer using a unilateral mastectomy?

Answer 58

~ 350 days

Question 59

what is the median survival time of feline mammary cancer using a regional mastectomy?

Answer 59

> 400 days

Question 60

what are transmissible venereal tumors?

Answer 60

naturally occurring horizontally transmitted tumor of dogs that has a worldwide distribution with coital transmission being common

Question 61

where can TVT be located?

Answer 61

external genitalia, nasal cavity, oral cavity, subcutaneous tissues, & eyes

Question 62

what is a risk factor of TVT?

Answer 62

immunosuppression

Question 63

what is the latency period of TVT?

Answer 63

1-2 months

Question 64

what is the suspected origin of TVT?

Answer 64

histiocytic origin

Question 65

T/F: up to 17% of TVT can metastasize

Answer 65

true

Question 66

how are TVTs transmitted?

Answer 66

directly from dog to dog allograft cellular mode of transmission - constant karyotype of 59 chromosomes normal dogs have 78 chromosomes

Question 67

what are the clinical signs of TVT?

Answer 67

common in intact sexually active male dogs living in an endemic area discomfort/bleeding from genitalia male dogs - glans penis female dogs - caudal vagina or vestibule

Question 68

how are TVTs staged?

Answer 68

local lymph node aspirates good physical exam - especially of the face cbc, chem, ua

Question 69

how are TVTs diagnosed?

Answer 69

FNA, biopsy look for round to oval nuclei, abundant pale cytoplasm, 1-2 nuclei, discrete clear vacuoles in cytoplasm

Question 70

what tumor type is seen on this cytology?

Answer 70

TVT

Question 71

what tumor is this?

Answer 71

TVT

Question 72

what are the treatment options for TVT?

Answer 72

chemotherapy radiation therapy surgery

Question 73

T/F: benign canine mammary tumors in situ & hyperplastic mammary tissues all have high estrogen receptors & progesterone receptors

Answer 73

true - steroid receptors decrease with malignancy