01 - skin tumors

Question 1

1. definitive diganosis of tumors is through what?

Answer 1

1. histopathology

Question 2

1-3. what are the three most common horse tumors seen by vets?

Answer 2

1. skin tumors
2. tumors of the sinuses and nasal passages
3. lymphosarcoma

Question 3

(tumors of the skin)

1. most common form of tumor in the horses
2. what are the three most common?

Answer 3

2. sarcoids, SCC, melanomas

Question 4

(tumors of the skin)

(sarcoids)

1. related to genetics and what virus?
2. can be found anywhere - usually where though?
3. often found in areas of repetitive trauma or injury

Answer 4

1. bovine papillomavirus
2. limbs and head

Question 5

(tumors of the skin)

(sarcoids)

1-4. what are the four main types?

Answer 5

1. occult (flat with no hair)
2. verrucuous (warty and small)
3. nodular
4. fibroblastic (aggressive, look like granulation tissue)

Question 6

(tumors of the skin)

(sarcoids)

1. are these metastatic?

Answer 6

1. never

Question 7

(tumors of the skin)

(sarcoids)

1. common in what three breeds?
2. generally what age?

Answer 7

1. quarter horses, appaloosas, and arabians
2. younger horses (1-6)

Question 8

(tumors of the skin)

(sarcoids)

(dx)

1. not recommended to bx - why?

Answer 8

1. trauma may turn into fibroblastic types

(however definitive dx based on histo)

Question 9

(tumors of the skin)

(sarcoids)

(tx)

1. many different treatments
2. surgical excision has high rate of recurrence (50%)
3. other txs = cryo, laser, cisplastin or 5-fluoruracil, radiation

Question 10

(tumors of the skin)

(SCC)

1. most common tumor of what location on horse?
2. what areas are predisposed?

Answer 10

1. eye and external genitalia

(also found in stomach, oral, bladder)

2. light colored areas (solar radiation)

Question 11

(tumors of the skin)

(SCC)

1. common in older horses
2. what kinds of horses predisposed?

Answer 11

2. light colored horses

Question 12

(tumors of the skin)

(SCC)

1. Cx?

Answer 12

1. depends on location

smell really bad

can often bleed/have discharge

Question 13

(tumors of the skin)

(SCC)

1. dx?

Answer 13

1. histo or cyto

Question 14

(tumors of the skin)

(SCC)

(tx)

1. many treatment available
2. sx excision best combined with adjunctive
3. local chemo with what?
4. others: cryo, radiation
5. also find that NSAIDs can help cause SCC makes COX-2 which aids in tumor growth and mets

Answer 14

3. intralesional 5-fluorouracil or cisplatin

Question 15

(tumors of the skin)

(SCC)

(prog)

1. ?

Answer 15

1. good if treated before spread/mets

bad if involve LN

Question 16

(tumors of the skin)

(melanomas)

1. cause unknown
2. mets?

Answer 16

2. usually slow growing and only local, but can become fast growing and have mets to internal organs

Question 17

(tumors of the skin)

(melanomas)

(signalment)

1. what horses get most?
2. more often malignant in gray or non-gray horses?
3. sex predilection?

Answer 17

1. older (15+) gray horses

(75% of older gray horses develop melanomas)

2. non-gray
3. no

Question 18

(tumors of the skin)

(melanomas)

1. 3 common areas?

Answer 18

1. under the tail, perineal region, external genitalia

Question 19

(tumors of the skin)

(melanomas)

1. dx?

Answer 19

1. can be based on gross appearance and common signalment

can be confirmed by cyto or histo

Question 20

(tumors of the skin)

(melanomas)

(tx)

1. often leave alone if small - but best to treat when small…
2. tx options = sx excision

cisplatin/cryotherapy

Question 21

(tumors of the skin)

(melanomas)

(prog)

1. tx recommended for small lesions before they become large, but not always recommended if small
2. gray horses with large, rapid growing and non-gray horses with melanomas should be examined closely for mets - which give a poor prog

Question 22

(tumors of the skin)

(melanomas)

(uncommon skin tumors)

Answer 22