Non-inflammatory diseases of the mammary gland Flashcards
1
Q
What changes does the mammary tissue undergo in puberty and pregnancy?
A
- puberty - duct proliferative - due to oestrogen, prog, GF, PL etc
- pregnancy - enlargement - then involution of glands, and acinar tissue disappears
2
Q
What are the non-neoplastic lesions of the mammary gland?
A
- cystic dilation of mammary ducts
- mammary tissue hypertrophy
- mammary tissue hyperplasia
3
Q
What is mammary hypertrophy?
A
- common in dogs and cats
- related to obstruction of duct by periductal fibrosis
- ep cells still producing milk - so get build up - dilation of duct - the ep accomodates by a lining that is attenuated or normal
4
Q
What is cystic dilation of mammary ducts?
A
- whole mammary gland is enlarged
- pseudopregnancy
- neutering while in dioestrus
- lactation
- phantom preg
- disbalance of hormones
5
Q
What is localized mammary hyperplasia?
A
- either the ep of the duct or the lobule of the gland
- papillary hyperplasia - incidental finding
- Lobular hyperplasia - enlargement of one or more lobules
- 3 mechanisms:
- hyperplasia of ep on the acinar - increase in secretions so dilation
- Adenosis - basiloid cells in lumen
- fibroadenomatous hyperplasia
- 3 mechanisms:
6
Q
What is fibroadenomatous hyperplasia?
A
- common in cats under 2 (intact)
- occurs in luteal phase, high prog serum conc, after progestin therapy, early in preg
- Hyperplasia is mediated by progesterone through GH and insulin-like growth factor 1
- fibroadenomatous hyperplasia = proliferation of fibrous tissue
7
Q
What are the general characteristics of mammary neoplasia?
A
- most common in dogs, cats, rodents
- reduce risk: spay before 1st oestrus
- better prognosis if have ER/ PG receptors
- dogs - 60-70% benign
- cats - 80-90% malignant
- most common tumour apart from on skin
- purebreds - higher risk
- early excision needed
8
Q
mammary neoplasia in dogs?
A
- hyperplasia -> dysplasia -> benign neoplasia -> malignant neoplasia
- spaying before 1 st oestrus - 0.05%
- after 1st/ before 2nd - 0.8%
- after 2nd - 26%
9
Q
What are the most common tumour types in dogs?
A
- benign mammary tumours (over 50%)
- epithelial, mixed ep, myoepithelial
- histologically:
- minimal invasion
- minimal anikaryosis/ pleumorphism
- low mitotic index
- adenomas
- fibroadenomas
- benign mixed tumours
- ductal papillomas
10
Q
Describe the dogs benign mammary neoplasms
A
- adenoma:
- simple - proliferation of luminal ep cells
- complex - proliferation of secretory ep cells, myoepithelial cells
- fibroadenoma - ep and stomal cells
- benign mixed tumour - mesenchymal and glandular elements
- ductal papilloma - papillomatous projections into distended lumen - with ep and myoepthelial cells around it
11
Q
What mammary malignant neoplasia do dogs get?
A
- carcinomas
- heterogenous
- 10% metastatic rate
- poor prognosis
- older dogs
12
Q
What malignant mammary neoplasias affect dogs?
A
- carcinomas
- tubulopapillary - luminal ep cells
- solid - luminal ep cells
- spindle - spindle cells in a solid ep arrangement - form bundles/ nests
- osteocarcomas
- carcinosarcoma
13
Q
What is the prognosis of carcinomas dependent on?
A
- grade
- age of dog
- size (>3cm)
- metastasis to lymph nodes
- lymphatic invasion
- peripheral infiltration growth pattern
14
Q
What % of dog mammary tumours are sarcomas?
A
- 5%
- bad prognosis
- most common is osteosarcoma
- 6,12,24 month survival - 50,30,10%
15
Q
Describe mammary tumour of cats
A
- less common
- 75-90% - carcinomas
- metastisise - to liver, lungs
- siamese
- normally found adjacent to nipple
- less heterogenous
- 7-9 years
- cats spayed before 1 year - lower risk
- age at diagnosis
- >3cm
- aggressiveness of surgery
- presence of lymph node involvement
- grade
