Equine Oncology

Question 1

What prognosis does an intestinal lymphosarcoma in a horse carry?

Answer 1

Very poor

Question 2

What is a common testicular tumor of horses?

Answer 2

Seminoma

Question 3

Unilaterally enlarged testicle that palpates firm and fibrous is likely affected by what tumor?

Answer 3

Seminoma

Question 4

How does a seminoma affect sperm production?

Answer 4

Decreases it

Question 5

What is a common ovarian tumor of horses?

Answer 5

Granulosa-theca cell tumor

Question 6

Unilateral benign tumor of the ovary that secretes steroids

Answer 6

Granulosa-theca cell tumor

Question 7

What do steroids produced by granulosa-theca cell tumors prevent?

Answer 7

Prevent cycling by suppressing gonadotropins

Question 8

What are ddx for aggression in mares?

Answer 8

Hypothyroidism and granulosa-theca cell tumors

Question 9

Why do granulosa-theca cell tumors cause aggression in mares?

Answer 9

Lead to incr. testosterone

Question 10

Which breed of horse is most predisposed to sarcoids?

Answer 10

Quarterhorse

Question 11

Non-malignant, non-metastatic, locally aggressive fibroblastic tumor of the dermis

Answer 11

Sarcoid

Question 12

What is the etiology of equine sarcoids?

Answer 12

Bovine papillomavirus may play a role

Question 13

How is equine sarcoids transmitted?

Answer 13

Direct contact, fomites, arthropods

Question 14

What are the three types of equine sarcoids?

Answer 14

Flat, verrucous, fibroblastic

Question 15

Slow-growing sarcoid that can be confused with a wart

Answer 15

Flat sarcoids

Question 16

Warty sarcoid that looks like a SCC or papilloma

Answer 16

Verrucous sarcoid

Question 17

Sarcoid that resembles granulation tissue or proud flesh and grows rapidly

Answer 17

Fibroblastic sarcoid

Question 18

How do you treat equine sarcoids?

Answer 18

Benign neglect for small lesions

Sx excision for larger lesions (cryo/radiation)

Question 19

Do sarcoids regress?

Answer 19

No

Question 20

What is the most common reason that sarcoids proliferate/grow?

Answer 20

Treatment/iatrogentic (messing with them makes them angry)

Question 21

What color horses are most commonly diagnosed with melanomas?

Answer 21

Gray horses

Question 22

What is a common site for equine melanoma?

Answer 22

Perineum and tail base

Question 23

What are characteristics of equine melanoma?

Answer 23

Dark pigment, slow growing, locally invasive

Question 24

Where do MCTs usually develop on a horse?

Answer 24

Dermis/subcutis on head/legs

Question 25

What tumors can be walled off by aggregates of fibrous stroma in horses?

Answer 25

MCTs

Question 26

What is the prognosis for equine MCT?

Answer 26

Excision is curative (good px)

Question 27

Are MCTs in horses malignant or benign?

Answer 27

Benign