Mammary Gland Pathology Flashcards
What is Clinical Mastitis?
An inflammatory response to infection causing visibly abnormal milk as the extent of the inflammation increases
What is SubClinical Mastitis?
The presence of an infection without the signs of local inflamation or systemic involvement
What is Chronic Granulomatous Mastitis most commonly caused by?
- Ocassionally observed in old sows
- Most cases are caused by S.Aureus
What is the usual case fatality rate of mastitis in sheep and ewes?
Can be as high as 50%
What is often an indicator of mastitis in camelids?
Poor Cria Growth Rate
What would mastitis look like in dogs and cats?
- Severley affected glands are large, firm and edematous
- overlying skin becomes taut and shiny
- small amount of grey secretion may be expressed
What are the three most common non-neoplastic lesions
mammary masses
- Cystic Dilation of Mammary ducts
- Mammary Hypertrophy
- Mammary Hyperplasia
What is Cystic dilation usually secondary to?
Obstruction of a duct or the papillary canal by periductal fibrosis
How does cystic dilation occur?
Continued Secretion and build up of content dilates the duct
* epithelium accomodates the larger diameter by attenuating the lining
What is mammary hypertrophy?
Mammary Gland becomes larger than normal for the physiological state
e.g lactation, pseudopregnancy, spaying
What are the three main manifestations of lobular hyperplasia?
- Hyperplasia of the epithelium of glandular acini
- Adenosis- epithelium undergoes hyperplasia and the lumen is filled with basiloid epithelial cells
- Fibroadenomatous hyperplasia
What animals is fibroadenomatous hyperplasia most common in?
Common in cats, especially intact females under 2
When does fibroadenomatous hyperplasia occur?
Occurs in the luteal phase of oestrus, early in pregnancy, or after progestin therapy
How does progesterone mediate hyperplasia?
Via Growth hormone and Insulin-Like Growth Factor
What are benign mammary neoplasias divided into?
- Adenomas
- Fibroadenomas ‘
- Benign Mixed Tumours
- Ductal Papillomas
Which bacteria is much less common due to dry cow therapy?
Streptococci
What bacteria may indicate heavy environmental contamination?
- Pseudomonas
- Prototheca
What are the main clinical signs of MMA?
- Sows become Lethargic, Anorexic and develop fever
- Failure of lactation and systemic signs dominate
What bacteria commonly causes mastitis in sheep and goats?
- S.aureus
- Mannheimia haemolytica
What is the most common mastitis causing bacteria in dogs and cats?
Staphylococci
In what animal species is cystic dilation common?
Common in dogs and cats
What three things can cause mammary hypertrophy?
- Lactation
- Pseudopregannacy (overproduction of milk)
- Spaying whilst in diestrus
Papillary hyperplasia is often an incidental finding of…?
Cystic ductal dilation
What are the three main manifestations of lobular hyperplasia?
- Hyperplasia of the epithelium
- Adenosis
- Fibroadenomatous hyperplasia
What does a simple adenoma look like histologically?
benign non-cancerous tumour
Proliferation of well-differentiated luminal epithelial cells
What does a complex adenoma look like histologically?
Mixed proliferation of secretory epithelila cells, resembling myoepithelial cells in a mucinous stroma
What does a benign mixed tumour look like?
Proliferation of glandular and mesenchymal elements
What does a duct papilloma look like?
Papillomatous projections in distended ducts, lined by epithelial and resting myoepithelial cells, supported by stalks of vascularised connective tissue
What is a tubulopapillary carcinoma?
Proliferation of cells resembling luminal epithelial cells with tubular or papillary arrangement.
What is the prognosis of feline neoplasias based on?
- Age at diagnosis
- Volume/ Diameter of the tumour
- Aggresivenes
- Grade
- Presence of lymph nodes
What is cystic dilation?
Continued secretion and build up of content dilates the duct
epithelium then accomodates the larger diameter that is attenuated or normal in appearance
What are the four carcinomas found in dogs?
- Tubulopapillary
- Solid
- Osteosarcoma
- Carcinosarcoma
What does the percentage likelihood of neoplasia in dogs go down to after an Ovariectomy?
0.05% if done before the first oestrus
