Exam 2: Equine Sarcoids and Melanoma Flashcards
This spontaneous, locally invasive, fibroblastic skin tumor
is the most common tumor on the horse.
Sarcoids
T/F: Sarcoids are usually metastatic tumors
FALSE
What is the etiology of equine sarcoids?
Bovine Papilloma Virus (BPV)
What do you expect to see on histology of a sarcoid lesion?
Hyperplastic/keratotic epidermis
RETE-PEG formation
Irregularly arranged fibroblasts (WHORLS)
NO invasion of underlying muscle
This treatment for Sarcoids has a success rate of 96%
Chemotherapy
Which chemotherapeutical agent is used to treat sarcoids and
hows is it given?
Cisplatin- 4 intratumoral injections 2 weeks apart
What is the treatment of choice for sarcoids that are disseminated throughout the body?
BCG (Bacillus-Calmette-Guerrin) Immunotherapy
What are the types of sarcoids?
Fibroblastic (proud-flesh like)
Verrucous (wart-like)
Occult (slightly raised)
T/F:
Sarcoids can regress on their own if they are small enough
TRUE
What are 5 differentials that should be on your list if you suspect sarcoids?
Exuberent granulation tissue
Fibrosarcoma
Cutaneous habronemiasis
SCC
Dermatophytosis (resembles verrucous sarcoids)
What are the 6 ways you can treat sarcoids?
Spontaneous regression
Surgical excision
Cryosurgery
Radiation
Chemotherapy
BCG Immunotherapy
___________ are tumors that arise from the malignant transformation of
normal melanocytes
Melanomas
This is the SECOND most common tumor in horses
Melanomas
What type of horses are melanomas most commonly seen in?
GRAY horses, OLD horses
What are the types of melanomas?
Slow-growing
Benign
Malignant
Metastatic
What are the most common locations to see melanomas?
Perineal region (most common)
Ventral tail
Lips
T/F:
Melanomas found growing on intestines can cause colic
FALSE!
Melanomas DO NOT grow on intestines,
but they CAN cause colic (especially if in the perineal region and ulcerate)
How is diagnosis of melanoma confirmed?
Biopsy
What are the most common areas to see sarcoids?
Head, legs, ventral abdomen
What type of surgery is indicated for a melanoma in the eyelid region?
Sliding Flap Technique
(with creation of Burow’s triangles)
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!
4 cm (2 inches)
T/F: Melanomas in the perineal region must be surgically resected
FALSE! Cannot do surgery on the perineal area
This medication is used systemically as a non-specific treatment for melanomas.
It is an H2-receptor antagonist that blocks pigment synthesis
CIMETIDINE
What is the arrow pointing to?
Burow’s Triangles
What is your diagnosis upon seeing this on histopathology
of a mass removed from the perineal area of a gray horse?
Melanoma
What is your most likely diagnosis?
Melanoma
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?
FIBROBLASTIC SARCOID
Classify this sarcoid, found cranial and medial to this horse’s eye.
OCCULT sarcoid
This is seen on histology of a mass removed from the
ventral abdomen of a horse. What is your primary ddx and why?
SARCOID!
Can see the epidermal component with epithelial pegs extending deep into the
underlying tissue
Healing of cryosurgical sites is always by__________
2nd intention
What is the best treatment for LARGE sarcoids?
surgical excision followed by cryotherapy
BCG, used in the treatment of small sarcoids in inaccessible areas via immune stimulation
is an attenuated strain of this bacteria
Mycobacterium bovis
The prevalence rate of melanomas can be as high as ______% in adult gray horses
80%!!
If left untreated, ________ of all melanomas can progress to malignancy
2/3
T/F: Melanomas are more likely to be malignant in gray horses
FALSE!
More likely to be malignant in NON-GRAY horses, even though overall prevalence is highest in grays
Hyperthermia can be used to treat ___________
while
Cryotherapy can be used to treat __________
Hyperthermia- MELANOMA
Cryotherapy- SARCOIDS
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?
Melanoma that had metastatized to the spleen
