Sarcoids Flashcards
Incidence of equine neoplasia
Overall incidence unknown but far less common than other species
Most commonly affected body system in integument
Sarcoid incidence
Most commonly reported neoplasm (up to 67%)
Overall prevalence is up to 2%
Sarcoid behviour
Benign but locally aggressive
Can have significant impact on local structures
Attract flies
Aetiology of sarcoids
Neoplastic proliferation of fibroblasts in association with infection with bovine papillomavirus types 1 and/or type 2
Lie-kely that the BPV is spread by flies
What are the 6 ‘clinical forms’ of sarcoids
Occult lesions
Verrucose sarcoids
Nodular sarcoids
Fibroblastic lesions
Mixed lesions
‘Malignant’ or ‘malevolent’ lesions
Occult lesions (sarcoids)
A hairless area (or area with very little hair) which are usually, but not always circular
Can resemble ringworm
Easy to miss
Verrucose sarcoids
Characteristic ‘warty’ appearance
Crusty, grey, dry areas of skin, can appear heavily keratinised
Difficult to treat as topical doesnt penetrate them well and not enough bulk to inject accurately
Can become widespread
May be more likely to recur
Nodular sarcoids
Often present as relatively discrete nodule
Freely removable from underlying structures
Can become infiltrative and adhere to underlying structures, especially in periocular region
Discrete lesions usually simple to treat
Fibroblastic sarcoids
Ulcerative
Often quite discrete in early stages
Usually easy to treat in early stages but can become very difficult if allowed to grow uncontrollably
Mixed sarcoid lesions
Can be challenging because they represent a more mature lesion that has been in situ for a longer period of time
Often affect a wider area
Malignant/malevolent sarcoids
Incredibly rare
Spread and invade more widely
Generally have an extremely poor prognosis
Predilection sites for sarcoids
Periocular region
Axilla
Inguinum
Sheath
Areas where the hair is thinner or absent
Complications associated with wounds - any non-healing wound should be biopsied to rule out neoplastic involvement
Diagnosis of sarcoids
Usually presumptive, visual diagnosis
Rarely achieve a definitive diagnosis as it is unlikely to affect treatment options
Does affect prognosis so biopsy is still recommended
Treatment options for sarcoids
In order of effectiveness:
Radiotherapy
Laser surgical resection
Electrochemotherapy
Intralesional treatments
Topical treatments
Other (variable)
Radiotherapy - plesiotherapy for sarcoids
A radioactive source is held directly to the lesion
Strontium-90 plesiotherapy reported for sarcoid treatment
- beta source with limited penetration
- only suitable for small, superficial lesions
Reported success rate is excellent
Limited availability (only in cam)
Radiotherapy - brachytherapy for sarcoids
Traditional treatment for periocular sarcoids
New system of high dose rate brachytherapy with iridium
Primarily gamma radiation for good penetration
Success rates >90% for periocular lesions
Performed under sedation
Gold standard for periocular sarcoids
Radiotherapy - teletherapy for sarcoid teatment
Delivered by linear accelerator
Beams of high energy electrons (beta) or gamma rays
Can select the penetrative ability
Requires GA
Rarely indicated for use
Excellent success rates
Limited availability (only in cam)
Possible complications of radiotherapy
White hair formation anf alopecia
Maybe some scar tissue
Transient self-limiting uveitis
Laser surgical excision for sarcoids
Most commonly achieved with a diode laser
Practical, effective, readily accessible
Success rates about 80%, less with verrucose lesions
Warn owners that it leaves an open wound left to granulate and heal by second intention
Effectively forms a burn
May take weeks to months to heal
Possible complications of laser resection for sarcoids
Development of a non-healing wound and recurrence of the sarcoid
Occasionally aggressive transformation os the lesion has been noted
Electrochemotherapy for sarcoid treatment
Used in conjuction with intralesional cisplatin, and often also with aser resection
Requires GA
ECT enhances the penetration of cisplatin to improve success rates
May lead to necrosis of the treated area and a wide slough, severe oedema and pain
Intralesional therapy for sarcoids
Need enough lesion (bulk) to go into
Not suitable for lesions without reasonable bulk, verrucose or occult lesions, or those with indistinct margins
Can use:
- Cisplatin
- Carboplatin
- Mitomycin C
- Tigilanol tiglate
- Immunocidin Equine
Cisplatin/carboplatin for intralesional sarcoid therapy
Reported success rate in literature >90%, in reality <70%
Significant health and safety concerns - platinum based chemotherapy. Serious risk of human exposure
Mitomycin C for intralesional sarcoid therapy
Very limited literature
Nodular and fibroblastic lesions
Leads to skin necrosis and sloughing
Success rates?
