Neoplasia Ch8 Flashcards
Which stains can be used to look for mast cell tumours
Giemsa
Toluidine blue
What is Fontana-masson silver stain used for
Stains melanin granules - melanocytic neoplasia
What stain is used to detect melanocytes
Melan-A
What is the most common skin tumour of cattle & what is the aitiologic agent?
Papillomas
Bovine palillomavirus
2 histologically distinct types of papillomas
1) Squamous papillomas - entirely squamous epithelial proliferations, and
2) Fibropapillomas - those with proliferation of underlying fibrous connective tissue as well as of epithelium.
Which bacteria are associated with interdigital papilloma in cattle?
Spirochetes. Usually respond to pen/ceftiofur or topical oxytet
Tx options for papillomas in cows?
How does this differ for sheep?
Cows - most undergo spontaneous regression, esp in younger animals. Can exicse 1 lesion or use immunostimulants to help speed up, although requirement unclear
Sheep - less likely to spontaneously regress & can undergo malignant transformation to SCC. Surgical excision or cryotherapy often curative.
What neoplasm may papillomas transform into?
SCC
Common predilection sites for SCC in cows, sheep, goats & pigs
Cows - mucocutaneous junctions, (eyes, vulva), udder. Older Herefords & Ayreshires predisposed
Sheep - ears, muzzle, lower lip, vulva, perineal region (post strike). Older Merino esp
Goats - mainly older females & common around the udder assoc. w papillomas. Angora, Saanen, and Saanen crosses are predisposed
V rare in pigs (despite non-pigmented skin). No known predilection site
Tx options for SCC
Wide sx excision, cryotherapy, hyperthermia, or radiation therapy of tumours before mets can be curative
NB immunotherapy can INCREASE rate of mets in sheep
Clinical features of melanomas in pigs
Lesions are solitary or multiple and occur as either flat plaque-like tumours or larger raised tumours, most often on the trunk
In predisposed breeds (Sinclair, Duroc-Jersey), the flat tumours typically spontaneously regress from as early as 1 month old, often leaving a halo of depigmented skin and hair behind
Larger, raised tumours often metastasise within the first year
Clinical features of melanomas in cattle
Usually younger animals - either present at birth or develop within 2 yrs, usually grey haired or potentially black or red haired cows.
Most commonly occur on the head (especially the jaw), neck, trunk, or legs.
Most tumours arise in areas of pigmented hair. Their size is variable (5-25cm) & usually solitary lesions with intact overlying skin
Lesions in young cattle are almost always benign and wide sx excision often curative
More likely metastatic in older animals
Clinical features of melanoma in sheep/goats
Usually older animals. Can be single or multicentric.
Tumours of sheep and goats are commonly malignant & metastatic
Perineal and horn-base melanomas of goats can exhibit widespread mets to multiple LNs, bone and internal organs, incl lungs, liver, adrenals and kidneys.
Sx excision of cutaneous lesions in goats can be attempted, but death from mets is common
3 most common orbital neoplasms in cattle
1 - SCC
2 - squamous papilloma
3 - orbital lymphoma
Which tumour of the jaw may occur in adult sheep & grazing what plant is associated with it?
Fibrosarcoma
Assoc w grazing bracken fern
