Skin masses in equines SDL

Give the 3 most common equine skin neoplasias

-melanoma

-Sarcoid

-Squamous cell carcinoma

what to consider in the history and clinical exam

Patient signalment (age/breed/sex)?

Where is the mass?

How long has it been there?

Colour?

Size?

Shape?

Ulcerated?

Painful to palpation ?

Speed of growth?

Normal hair / hair has fallen out?

what might be on you ddx list when looking at equine skin masses

Neoplasia

Abscess

Cyst

Eosinophilic granuloma

Papilloma (warts)

how is diagnosis achieved

Diagnosis achieved by history, clinical appearance and sometimes biopsy.

Describe a melanoma

Black, spherical or plaque like masses that are most common around the perineum and parotid region on grey horses

Describe a sarcoid

These masses are usually hairless, sometimes ulcerative and most commonly found in the groin, axilla and around the eyes

Describe squamous cell carcinoma

These masses can be described as raised, irregular, pink, locally invasive

-They are most common around the genitals and eyes

Describe sarcoids

-Most common skin tumour in horses

-Locally invasive

-Fibroblastic

-wart -like

-6 different types of sarcoids

-multiple lesions are more common

how to diagnose a sarcoid

Diagnosis is usually made by visual appearance alone, but can be confirmed by biopsy

Describe the histological appearance of sarcoids?

Increased density of dermal fibroblasts which form interlacing bundles and whorls within the dermis

What contributes to the development of equine sarcoids?

Bovine papillomavirus

How are sarcoids transmitted?

-flies act as vector for transmission of the virus allowing sarcoids to be passed from one horse to another

-Flies usually reside in the groin, around the axilla and eyes

What are the types of sarcoid?

-occult

-Verrucose

-nodular

-Fibroblastic

-Malignant

-Mixed

What is a mixed lesion?

Areas of two or more types of sarcoids with no distinguishable margin between them

Occult

Verrucose

Nodular

Fibroblastic

Malignant

Mixed (verrucose with fibroblastic parts)

Describe treatment for sarcoids

-Sarcoids do not always require treatment if they are small, slow growing, not ulcerated / bleeding and do not interfere with tack.

-Even so, early treatment is usually a good idea to prevent lesions becoming large and to reduce the risk of spread to other locations on the same horse and to other horses.

What are the treatment options of sarcoids?

1) Laser surgical removal - A laser is preferred to a scalpel as it reduces the risk of recurrence, bleeding and post operative pain.

2) Cryotherapy

3) Caustic cream application

4) Elastrator band application (causes hypoxic necrosis in nodular sarcoids).

5) Radiotherapy (particularly for periocular sarcoids)

Describe the treatment of melonomas

It is reasonable to leave many melanomas untreated, but sometimes early removal is beneficial. In particular those around the anus can be removed easily with a surgical laser, to prevent future defacation difficulties

describe melanomas

• usually benign, black, nodular, slow growing, firm nodules

• that occur most commonly on the perineum, sheath and parotid region of grey coloured horses.

how to diagnose melanomas

Diagnosis is usually made on visual appearance.

What are the most common locations of squamous cell carcinoma?

-Penis

-Third eyelid

what are squamous cell carcinomas

are locally invasive, pink, irregular, sometimes ulcerated lesions which can grow rapidly

How is squamous cell carcinoma treated?

All SCC should be excised as they can rapidly progress and spread,

this is usually curative - complete removal should be confirmed histologically

Describe eosinophilic granuloma

-Eosinophilic granuloma are small, non-itchy, firm, round, non-painful, raised nodules, with normal hair covering.

Where are eosinophilic granulomas located?

-They can be located anywhere on the body but are found most commonly on the withers and back.

What are the causes of eosinophilic granulomas?

-They are not neoplasia but their actual cause is unknown.

-There is some evidence that they are a type of hypersensitivity reaction to insect bites or may follow trauma e.g. ill fitting tack.

How are eosinophilic granulomas diagnosed?

Diagnosis is by clinical appearance, fine needle aspirate or biospy.

How are eosinophilic granulomas treated?

Treatment is often not required, but surgical excision or injection with corticosteroid may be performed if they are interfering with tack.

What are juvenile papillomas?

Multiple, small, irregular, verrucose, grey, proliferative lesions

Where are juvenile papillomas (warts) located?

Most commonly found on the muzzle, face and sheath of young horses

What are juvenile papillomas caused by?

Caused by equine papilloma virus

How are juvenile papillomas treated?

-diagnosis is by clinical appearance (and possibly biopsy).

- They are usually self-limiting so that treament is not required, but cryotherapy may be considered if they are severe.

Juvenile papilloma (warts)

 

Eosinophilic granuloma

Eosinophilic granuloma

Squamous cell carcinoma

Squamous cell carcinoma

Squamous cell carcinoma

melanoma

melanoma

describe mixed sarcoid

Areas of 2 or more types of sarcoids with no distinguishable margin between them. (This one is verrucose with fibrobalstic parts).

describe malignant sarcoid

A rarer form of sarcoid which have extensive rapid spread over a wide area of skin with cords of sarcoid tissue interspersed with nodules and fibroblastic lesions.

describe fibroblastic sarcoid

Ulcerative nodular masses that frequently bleed when knocked, they can appear like granulation tissue

describe nodular sarcoid

Firm round nodules within the skin, usually fixed within the skin, however the skin can normally move freely over the underlying tissue

describe verrucose sarcoid

plaques of cracked flaky irregular skin, often described as wart like.

The margins of these can be difficult to determine

describe occult sarcoid

flat often hairless areas of skin, can be subtle and difficult to spot, may even be difficult to determine from ringworm