Equine Oncology Flashcards
What prognosis does an intestinal lymphosarcoma in a horse carry?
Very poor
What is a common testicular tumor of horses?
Seminoma
Unilaterally enlarged testicle that palpates firm and fibrous is likely affected by what tumor?
Seminoma
How does a seminoma affect sperm production?
Decreases it
What is a common ovarian tumor of horses?
Granulosa-theca cell tumor
Unilateral benign tumor of the ovary that secretes steroids
Granulosa-theca cell tumor
What do steroids produced by granulosa-theca cell tumors prevent?
Prevent cycling by suppressing gonadotropins
What are ddx for aggression in mares?
Hypothyroidism and granulosa-theca cell tumors
Why do granulosa-theca cell tumors cause aggression in mares?
Lead to incr. testosterone
Which breed of horse is most predisposed to sarcoids?
Quarterhorse
Non-malignant, non-metastatic, locally aggressive fibroblastic tumor of the dermis
Sarcoid
What is the etiology of equine sarcoids?
Bovine papillomavirus may play a role
How is equine sarcoids transmitted?
Direct contact, fomites, arthropods
What are the three types of equine sarcoids?
Flat, verrucous, fibroblastic
Slow-growing sarcoid that can be confused with a wart
Flat sarcoids
Warty sarcoid that looks like a SCC or papilloma
Verrucous sarcoid
Sarcoid that resembles granulation tissue or proud flesh and grows rapidly
Fibroblastic sarcoid
How do you treat equine sarcoids?
Benign neglect for small lesions
Sx excision for larger lesions (cryo/radiation)
Do sarcoids regress?
No
What is the most common reason that sarcoids proliferate/grow?
Treatment/iatrogentic (messing with them makes them angry)
What color horses are most commonly diagnosed with melanomas?
Gray horses
What is a common site for equine melanoma?
Perineum and tail base
What are characteristics of equine melanoma?
Dark pigment, slow growing, locally invasive
Where do MCTs usually develop on a horse?
Dermis/subcutis on head/legs
