The lumpy horse

Question 1

what horses generally get melanomas

Answer 1

mostly grey horses
usually develop between 4-8 yrs

Question 2

List the 4 types of equine melanoma

Answer 2

melanocytic nevi
dermal melanoma
dermal melanomatosis
malignant melanoma

Question 3

what are the characteristic of melanocytic nevi

Answer 3

single or multiple discrete nodules

Question 4

what are the characteristics of dermal melanoma

Answer 4

Originate in deeper dermis
Small singular or multiple nodules

Question 5

what are the characteristics of dermal melanomatosis

Answer 5

Confluent large melanomas
Increased risk of metastasis

Question 6

What are the charcteristics of malignant melanoma

Answer 6

Not common, invasive
In older horses
Recurrence very likely

Question 7

List 4 typical locations of equine melanomas

Answer 7

Tail
Perineum
Parotid region
Commissure of lips/eyes

Question 8

How to diagnose equine melanomas

Answer 8

Visual inspection
Palpation
Ultrasound
Fine needle aspiration

Question 9

Decsribe anaplastic/ amelanotic malignant melanoma

Answer 9

Non grey and grey horses
Older horses
Tail and tailhead +++

Have metastasised by the time of diagnosis
Rare

Question 10

List the key features of equine sarcoids

Answer 10

Benign
Non-metastatic
Locally aggressive
In all equids
High recurrence

Question 11

List the 6 types of equine sarcoids

Answer 11

Occult
verrucose
nodular
fibroblastic
mixed
malignant

Question 12

Describe occult equine sarcoids

Answer 12

occur in hairless skin
1 or more small (2-5 cm) cutaneous nodules
Mildest/most stable/superficial form of sarcoid

Question 13

Describe verrucose sarcoids

Answer 13

Rarely aggressive
Rough hyperkeratotic appearance with some flaking or scaling
Warty-looking

Question 14

Describe nodular sarcoids

Answer 14

Very variable sizes, 0.5 to 20 cm
Firm, spherical, subcutaneous nodules
Two types

Question 15

What are the 2 types of nodular sarcoids

Answer 15

A: confined to subcutaneous tissues
B: some involvement of overlying skin

Question 16

Describe fibroblastic sarcoids

Answer 16

Ulcerated, fleshy, aggressive appearance
2 types

Question 17

Describe the 2 types of fibroblastic sarcoids

Answer 17

1: Pedunculated with limited/small base palpable under the skin
2: wide base, often diffuse/ill-defined margins

Question 18

Decsribe malignant/ Malevolent sarcoids

Answer 18

Most severe, highly invasive- Infiltration of lymphatic vessels
Often following trauma or failed treatment

Cord of palpable tumour

Question 18

Decsribe mixed sarcoids

Answer 18

Mixture of two or more types of sarcoid

Vary between verrucous/occult/nodular to fibroblastic

Question 19

what is the most common skin cancer of horses

Answer 19

equine sarcoids

Question 20

Describe transmission equine sarcoids

Answer 20

Not fully understood
possibly due to contact with sarcoids or contact with cattle/ horses carrying bovine papilloma virus

Question 20

Decsribe the key features of equine squamous cell carcinoma

Answer 20

Locally invasive, does metastasise

Question 21

List 5 predilections for squamous cell carcinomas

Answer 21

areas lacking pigmentation
poorly haired
mucocutaneous junctions
external genitalia
eye/adnexa

Question 22

List 4 predisposing factors to equine squamous cell carcinomas

Answer 22

Equus Caballus papillomavirus 2 (EcPV2) and others
Flies
Smegma
Ultraviolet light exposure

Question 22

Lust the 2 types of surgical excision of equine skin cancers

Answer 22

sharp excision
laser excision- currently favoured for sarcoid - and used a lot for melanoma

Question 23

when can banding be used to treat sarcoids

Answer 23

only for sarcoids with a thin peduncle
Not to be used if the mass has a root
Takes a few weeks

Question 24

when do we use topical chemotherapeutics for skin masses

Answer 24

for low mass burden only
DON’T use very close to eyes

Question 25

Describe electrochemotherapy

Answer 25

uses electrical field pulses to induce increased cell membrane permeability to certain antitumour hydrophilic drug like cisplatin

Question 26

List 2 topical chemotherapy creams

Answer 26

5-fluorouracil
Mitomycin C

Question 27

List 4 drugs that can be used for intralesional chemotherapy

Answer 27

Mitomycin C
Tigilinol tiglate
5 Fluorouracil
Platinum- based e.g. cisplatin or Carboplatin