Exam 2: Equine Sarcoids and Melanoma

Question 1

This spontaneous, locally invasive, fibroblastic skin tumor

is the most common tumor on the horse.

Answer 1

Sarcoids

Question 2

T/F: Sarcoids are usually metastatic tumors

Answer 2

FALSE

Question 3

What is the etiology of equine sarcoids?

Answer 3

Bovine Papilloma Virus (BPV)

Question 4

What do you expect to see on histology of a sarcoid lesion?

Answer 4

Hyperplastic/keratotic epidermis

RETE-PEG formation

Irregularly arranged fibroblasts (WHORLS)

NO invasion of underlying muscle

Question 5

This treatment for Sarcoids has a success rate of 96%

Answer 5

Chemotherapy

Question 6

Which chemotherapeutical agent is used to treat sarcoids and

hows is it given?

Answer 6

Cisplatin- 4 intratumoral injections 2 weeks apart

Question 7

What is the treatment of choice for sarcoids that are disseminated throughout the body?

Answer 7

BCG (Bacillus-Calmette-Guerrin) Immunotherapy

Question 8

What are the types of sarcoids?

Answer 8

Fibroblastic (proud-flesh like)

Verrucous (wart-like)

Occult (slightly raised)

Question 9

T/F:

Sarcoids can regress on their own if they are small enough

Answer 9

TRUE

Question 10

What are 5 differentials that should be on your list if you suspect sarcoids?

Answer 10

Exuberent granulation tissue

Fibrosarcoma

Cutaneous habronemiasis

SCC

Dermatophytosis (resembles verrucous sarcoids)

Question 11

What are the 6 ways you can treat sarcoids?

Answer 11

Spontaneous regression

Surgical excision

Cryosurgery

Radiation

Chemotherapy

BCG Immunotherapy

Question 12

___________ are tumors that arise from the malignant transformation of

normal melanocytes

Answer 12

Melanomas

Question 13

This is the SECOND most common tumor in horses

Answer 13

Melanomas

Question 14

What type of horses are melanomas most commonly seen in?

Answer 14

GRAY horses, OLD horses

Question 15

What are the types of melanomas?

Answer 15

Slow-growing

Benign

Malignant

Metastatic

Question 16

What are the most common locations to see melanomas?

Answer 16

Perineal region (most common)

Ventral tail

Lips

Question 17

T/F:

Melanomas found growing on intestines can cause colic

Answer 17

FALSE!

Melanomas DO NOT grow on intestines,

but they CAN cause colic (especially if in the perineal region and ulcerate)

Question 18

How is diagnosis of melanoma confirmed?

Answer 18

Biopsy

Question 19

What are the most common areas to see sarcoids?

Answer 19

Head, legs, ventral abdomen

Question 20

What type of surgery is indicated for a melanoma in the eyelid region?

Answer 20

Sliding Flap Technique

(with creation of Burow’s triangles)

Question 21

For surgery in the eyelid region to remove a melanoma,

the Sliding Flap Technique is used.

It is important to remember not to undermine > ______ cm;

any larger and the area with SLOUGH!

Answer 21

4 cm (2 inches)

Question 22

T/F: Melanomas in the perineal region must be surgically resected

Answer 22

FALSE! Cannot do surgery on the perineal area

Question 23

This medication is used systemically as a non-specific treatment for melanomas.

It is an H2-receptor antagonist that blocks pigment synthesis

Answer 23

CIMETIDINE

Question 24

What is the arrow pointing to?

Answer 24

Burow’s Triangles

Question 25

What is your diagnosis upon seeing this on histopathology of a mass removed from the perineal area of a gray horse?

Answer 25

Melanoma

Question 26

What is your most likely diagnosis?

Answer 26

Melanoma

Question 27

This mass was seen on the leg of a horse. It is mushrooming in appearance with an ulcerated surface that bleeds easily. What is your primary ddx?

Answer 27

FIBROBLASTIC SARCOID

Question 28

Classify this sarcoid, found cranial and medial to this horse's eye.

Answer 28

OCCULT sarcoid

Question 29

This is seen on histology of a mass removed from the ventral abdomen of a horse. What is your primary ddx and why?

Answer 29

SARCOID! Can see the epidermal component with epithelial pegs extending deep into the underlying tissue

Question 30

Healing of cryosurgical sites is always by\_\_\_\_\_\_\_\_\_\_

Answer 30

2nd intention

Question 31

What is the best treatment for LARGE sarcoids?

Answer 31

surgical excision followed by cryotherapy

Question 32

BCG, used in the treatment of small sarcoids in inaccessible areas via immune stimulation is an attenuated strain of this bacteria

Answer 32

*Mycobacterium bovis*

Question 33

The prevalence rate of melanomas can be as high as \_\_\_\_\_\_% in adult gray horses

Answer 33

80%!!

Question 34

If left untreated, ________ of all melanomas can progress to malignancy

Answer 34

2/3

Question 35

T/F: Melanomas are more likely to be malignant in gray horses

Answer 35

FALSE! More likely to be malignant in NON-GRAY horses, even though overall prevalence is highest in grays

Question 36

Hyperthermia can be used to treat \_\_\_\_\_\_\_\_\_\_\_ while Cryotherapy can be used to treat \_\_\_\_\_\_\_\_\_\_

Answer 36

Hyperthermia- MELANOMA Cryotherapy- SARCOIDS

Question 37

This spleen was seen on necropsy of a horse with a large, necrotic, dermal lesion at the base of its tail. What is your primary ddx?

Answer 37

Melanoma that had metastatized to the spleen