Lecture 14: Equine Neoplasia Flashcards
What is the most common neoplasm of horses, donkeys and mules
equine sarcoids
equine sarcoids are __skin tumors
nonmetastatic
where are equine sarcoids most commonly located
head, ventral, abdomen, limbs
what are the 4 morphologic types of equine sarcoids
- Flat
- Verrucous
- Fibroblastic
- Mixed
flat (occult sarcoids) are often __thickness
partial
what wrong/type
flat (occult) sarcoid
verrucous (horny) sarcoids will grow if __ or __
injured or biopsied
verrucous (horny) sarcoids may be __thickness
partial
what wrong/type
Verrucous (horny) sarcoid
fibroblastic sarcoids are usually __thickness
full thickness
what wrong/type
fibroblastic sarcoid
what wrong/type
mixed sarcoid
what are some differentials for sarcoids
- Exuberant granulation tissue
- Habronemiasis
- Fibroma
- Fibrosarcoma
- Neurofibroma
- Rare mesenchymal tumors
- Infectious/non-infectious granulomas
what do you need for histo dx of sarcoids
skin
what does histo of sarcoid look like
capillary poor, fibroblastic proliferation, fibroblasts oriented perpendicular, hyperplastic epidermis
what type of sarcoids must be treated
fibrogranulomatous lesions
do verrucous or flat sarcoids need to be tx immediately
no, but should be evaluated closely
if you are going to biopsy sarcoids what you need to do
excisional biopsy- need to take all of it
If you can’t do excisional biopsy what is other option, but you wont have skin
trucut biopsy
what are the sarcoid therapy options
- Sx excision (laser or conventional)
- Laser vaporization (CO2)
- Local chemo (always)
- Hyperthermia
- Immunotherapy
- Cryotherapy
- Radiation
What is procedure for surgical excision of sarcoid
margins as wide as possible, primary closure if possible
what tx of sarcoids has best prognosis
complete excision (wide and deep) with primary closure
with surgical resection with primary closure you can avoid __tissue
granulation
How does CO2 laser excision and vaporization work
resects and evaporates tissue, follow with primary closure or second intention healing
cryotherapy has __% free of recurrence
70%
cryotherapy is best applied via __
direct spray
what is procedure for cryotherapy
- Freeze rapidly to -20 to -30 C
- Monitor with thermocouples
- Don’t freeze bone
- 2-3 freeze-thaw cycles needed
what are some complications of cryotherapy
Swelling, hyperemia, hemorrhage, edema, necrosis, destruction of hair follicles, new hair-white, facial paralysis, septic arthritis, loss of eyelid, significant tissue contraction
70% strength loss in cryotherapy if __
freeze cortical bone
what is immunotherapy bacillus of calmette and Guerin (BCG) made of
attenuated strain of M. Bovis
what is downside of BCG immunotherapy
tuberculin +
what location of sarcoids is BCG most effective in
peri ocular
what is XXterra
herbal formulation of bloodroot powder and zinc chloride
what can XXterra tx
small sarcoid lesions
how does hyperthermia tx work
heat 50 C for 30 seconds, repeated
what is rationale for using CO2 laser removal on partial thickness sarcoids
- Partial thickness wounds don’t granulate- sarcoids tend to recur in granulating wounds
- More durable/efficient wound healing- no scar tissue epithelium
Perform partial thickness vaporization on this sarcoid- what wrong what you need to do
Pink spots still tumor- need to remove
what are your chemotherapy options for sarcoids
- Cisplatin beads or injections
- Fluoroacil crème
- Mitomycin C
__% fluororacil crème is used for tx of penis and stays in sheath. how often and how many days
5%, BID 7-10 days
penis sheath only 1 tx
__% fluorouracil crème is used for ocular/periocular SCC, how often
1%, 4-7 days, repeat same off period and then do 2-3 more times
what is difference between cisplatin beads and injections
beads: 1 month intervals, injections: 2 weeks
Injections must infiltrate entire mass because does not diffuse, beads diffuse 15mm
where do you not want to put cisplatin beads around eye and why
dorsal to eye- result in cisplatin slough
what is MOA of topical fluorouracil
inhibits RNA and DNA synthesis (pyrimidine analog)
treat __days with topical fluorouracil or until hypersensitivity appears
10-14 days
how should you apply topical fluorouracil and why
Q-tips- big reaction
what is protocol/days for ophthalmic ointment 1% fluorouracil
topical bid 4-7 days, same period off, repeat twice more
what is sarcoid tx plan for periocular sarcoids
Excision, laser, chemo
What is sarcoid tx plan for trunk and limbs
excision, debunk with laser or scalpel
during sarcoid tx you want to avoid __bed
granulation bed
what part of sarcoid tx plan helps avoid granulation bed
chemo
mass on flank- what is it likely and how do you remove it
Dx: subdermal fibroma
Can just pop it out of skin
what wrong and can you tx this
Malevolent sarcoid
Not going to win this
cutaneous SCC are common in what horses
lightly pigmented: Appaloosas, pintos, and paints
Draft horses
what 2 factors contribute to cutaneous SCC
UV light, altitude
what are some common locations of SCC
- Cornea/limbus, 3rd eyelid
- External genitalia geldings and mares
- Mucocutaneous junctions
- Hoof wall
- Secondary to burns
what wrong
precancerous lesion on penis- likely will turn into SCC
histo of mass- what is dx and what is characteristic of this histo
Dx: SCC
Histo: keratin pearl
what are some early physical manifestations of SCC
small, superficial nodules
what are some later physical manifestations of SCC
ulceration, necrosis, odor
what wrong
Erosive conjunctival SCC
what wrong
3rd eyelid SCC
after resection of SCC what do you always need to follow with
chemo
what are the tx options for SCC
- Laser or sharp resection/ vaporization
- Chemo- cisplatin
- Hyperthermia
- Debulking-cryotherapy
- Beta irradiation
- Corneal/conjunctival chemo (fluorouracil, mitomycin)
what chemos are used in corneal/conjunctival SCC tx
fluorouracil and mitomycin C
penile SCC- what is tx
amputate penis, chemo
what wrong and is this low or high risk
vulvar SCC- high risk can lose mares to this
Horse ear: what this
aural plaques
t or f: aural plaques do not resolve and do not have effective tx
true
What wrong
equine melanoma
what is melanocytic nevi
uncommon, younger horses, subepithelial melanin
what is dermal melanoma/ melanomatosis
very common, horses middle to older age, dermal melanin
what is anaplastic malignant melanoma
non gray horses, non-pigmened
Almost always fatal
which is melanocytic nevus vs dermal melanoma
left: melanocytic nevus- subepithelial melanin
Right: Dermal melanoma- dermal melanin
anaplastic malignant melanoma has extremely __ cells with numerous __ figures
pleomorphic cells, numerous mitotic figures
t or f: anaplastic malignant melanoma is rare, extremely metastatic
true
equine melanocytic tumors are typical in older __horses
gray or white
what are some common locations for dermal melanoma
ventral tail, perineum, external genitalia, parotid salivary gland, limb, neck, ears, eyelids, internal, lip, comminuted of mouth
dermal melanomas are ___when exceed blood supply
ulcerated/draining
what wrong- and how would you name these 2
Left: dermal melanoma
Right: dermal melanomatosis
what is tx for melanocytic tumors
- Wide sx margins
- Cisplatin sensitive
- Cryonecrosis- regrow to
- Laser hyperthermia
t or f: BCG immunotherapy and cimetidine are effective against melanocytic tumors
false
