Pathology of the female reproductive tract Flashcards
What is the structure and function of the ovaries?
development and release of ovum, production of hormones (estrogen and progesterone)
What is the structure and function of the uterine tubes?
transport of spermatozoa and ovum; fertilization
What is the structure and function of the uterus?
proper environment for the development of the conceptus
What is the structure and function of the cervix?
prevent the entrance of microorganisms
What is the structure and function of the vulva/vagina?
passage of spermatozoa, passage of the foetus, reduce contamination to the cervix
Portals of entry into the female reproductive tract
- Ascending through the vulva/cervix (oestrus, breeding and post partum)
- Hematogenous spread (less common, related to specific agents)
- Descending from the ovary (related to specific agents)
- Penetrating wall (rare)
- Transneural (Herpesvirus)
What are the defence mechanisms of the female repro tract?
Innate immunity
o Cervix isolate microorganisms
o Epithelial tight junctions
o Stratified epithelium in vagina
o Normal microflora
o Mucus
o Muscular contractions, gravity
o PAMP receptors and acute inflammation
Adaptive immunity
o Very well controlled and depending on the site
o Lymphoid follicles in vagina and vulva
Hormonal influence
o Increased resistance in oestrus: open cervix
o Estrogen x Progesterone
o Prostaglandins produced by epithelial cells of the endometrium (ex: ruminants, equine, swine): lysis of corpus luteum
How do the different components of the female reproductive tract respond to injury?
- Ovary: inflammation, hyperplasia of surface epithelium
- Uterine tube: inflammatory cells via recruitment and local (formation of lymphoid follicles) - very narrow, so any changes may interfere in its normal function (inflammation, including oedema and scarring)
- Uterus: inflammation, squamous metaplasia of the endometrium; cystic endometrial hyperplasia (dogs and cats)
- Vulva and vagina: hyperplasia and keratinization of the squamous epithelium; inflammation; lymphoid follicles may form
What circulatory disturbances do we see in the ovaries?
Haemorrhage/haematoma
- Mild follicular haemorrhage during ovulation occurs in all species
- In mares, large corpus hemorrhagicum may lead to ovary haematoma
- Significant haemorrhage after enucleation
What is oophoritis in the ovary?
- Relatively rare and mostly pyogenic
- Abscess (enucleation of corpus luteum/oocyte retrieval)
Other examples:
- Lymphocytic related to infertility in dogs
- Necrotizing in cows (Bovine herpesvirus)
- Chronic - BVD
Serosal granulomas
- Bovine Tuberculosis and Brucellosis
- FIP - Perioophoritis
What degenerations can occur in the ovary?
HINT: 1 separated into 2 categories
Paraovarian cyst
- Remnants of embyonic stuctures
Intraovarian cyst
- Cystic follicular disease Anovulatory cystic follicles Vs normal antral or tertiary follicles: follicles larger than normal, persistent and with associated signs of hyperestrogenism are features of cystic follicular disease. Important in cows: failure of mature follicles to ovulate; behaviour varies from nymphomania to anestrus
- Cystic subsurface epithelial structures in bitches – it may undergo neoplastic transformation
- Epithelial inclusion cysts – ovulation fossae in mares (infertility)
What are sex cord stromal tumours?
- Tissues derived from sex cords (tumors of granulosa and/or theca cells)
- Granulosa cell tumour; Thecoma; Granulosa-theca cell tumour
- Frequently produce hormones
- In dogs and cats, related to cystic endometrial hyperplasia and pyometra
- In mares, usually with atrophy of the opposite ovary (production of inhibin)
What are epithelial tumours?
- Originate from the surface epithelium
- Adenoma/Adenocarcinoma, Papillary and cystic
- Malignant tumours spread to peritoneum directly or by seeding
- Metastasise to lymph nodes and other organs.
What are germ cell tumours?
- Dysgerminoma - benign, undifferentiated
- Teratoma – benign, differentiated
What is hyperplasia often associated with in the ovary?
Often associated with the endomentrium
What are some examples of metastatic tumours?
- Lymphosarcoma, intestinal carcinoma (cow)
- Metastatic mammary carcinomas (bitch)
What is hydrosalpinx?
- Accumulation of fluid inside the uterine tubes usually related to an obstruction
- Dilated, fluid-filled tube
- Usually results from obstruction
- Obstruction can be related to previous inflammation and scaring or trauma
What kinds of inflammation do we see in the uterine tubes?
Salpingitis/pyosalpinx
- Inflammation of uterine tubes also associated with inflammation of the uterus
- Usually results from ascending bacterial infection and bilateral
- Together with endometritis, metritis, or pyometra in most species
- Descending infection from the ovary may occur with viral infection; hematogenous infection is possible
- Hyperaemia and intrauminal exudate: mild/severe, acute/chronic
- Pyosalpinx (pus-filled tube)
- Loss of cilia and desquamation; hyperplasia or squamous metaplasia
- Repair may result in hydrosalpinx and adhesions – infertility
What circulatory disturbances can occur in the uterus?
Hemorrhage
- Torsion (results in infarction)
- Subinvolution of placenta (dogs)
- Rupture of uterine artery
- Neoplasia
NOTE: Endometrial hyperemia and edema occur normally at oestrus
Endometritis and metritis
- Endometritis -> only effecting the endometrium
- Metritis -> progression of endometritis -> effecting all layers
- Uterine infections usually begin as endometritis, and many progress to involve the myometrium
- Mostly due to ascending bacterial when the cervix is open: oestrus, parturition and postpartum
- Haematogenous route: particularly in pregnancy (uteroplacental interface is the target for some microbes, such as Brucella, Coxiella and Chlamydia).
- Descend from the ovary and uterine tube or by direct extension from adjacent organs.
- In the mare and the cow, it may lead to persistence of the corpus luteum (destruction of endometrium and lack of PGF2α)
- Defence mechanisms and hormonal environment are determinant: susceptibility to infection varies in the cycle
- There may be little or no vaginal discharge
- Grossly: endometrium is swollen and red, with necrotic debris. Mild lesions are not detectable grossly.
- Microscopically: oedema and neutrophils in the stroma and glands
- Severe cases: progress to chronicity with fibrosis
- Inflammation progresses to myometrium, becoming metritis: the exudate may extend through the muscle layers to the serosa
What is pyometra?
- Acute or chronic suppurative inflammation in the uterus
- Progression from endometritis/metritis
- Uterus can be greatly distended by the intraluminal accumulation of pus
- Exudate can be discharged into the vagina
- Rupture can occur - peritonitis
- Particularly common in the bitch and the cow, but driven factors are different amongst species
What would you expect to see grossly in pyometra?
Grossly:
o Necrotic, ulcerated, and hemorrhagic areas with cystic changes
What would you expect to see microscopically in pyometra?
Microscopically:
o Neutrophils in the lumen, stroma and within glands
o Vacuolation, papillary projections and pseudostratification may occur in the endometrial epithelium (progesterone)
o Cystic endometrial changes
o Plasma cell and lymphocytes present
o In more chronic stages: fibrosis, squamous metaplasia
Are there species differences in pyometra?
**Bitches & Queens **
- Usually following cystic endometrial hyperplasia (Underlying Disorder of Growth)
- Usually associated with progesterone (luteal phase)
- Cervix is generally closed
- Often E.coli, Proteus, Staphylococcus, Streptococcus
- Often results in sepsis: life-threatening
- Three times more common in bitches than queens
Cows
- Following coitus (Tritrichomonas foetus), early embryonic death, retained foetal membranes (Actinomyces pyogenes, E.coli, Pseudomonas aeruginosa, Streptococcus, Staphylococcus)
- Endometrial damage prevents endometrium from producing sufficient PGF2α to cause luteolysis
- May be several litres of thick mucinous or grey green pus
- Not life-threatening, but cause of infertility
Mares
- May continue to cycle
- Persistent corpus luteum is not essential for pathogenesis
- Cervix usually open
- Significant cause of infertility
What disorders of growth can occur in the uterus?
- Atrophy
- Cystic endometrial hyperplasia - Hydrometra and mucometra
- Endometrial polyps
Neoplasia:
- Leiomyoma/sarcoma
- endometrial adenocarcinoma
- Lymphoma (cattle)
What is cystic endometrial hyperplasia (hydrometra and mucometra)?
- Common response in bitches and queens
- Oestrogen (priming) causes increased synthesis of progesterone receptors in endometrium (source of oestrogens can be endogen - granulosa cell tumours or exogenous)
- Oestrogen stimulation of the uterus followed by prolonged exposure to progesterone during diestrus
- Progesterone makes the endometrial epithelium looks enlarged, columnar, and vacuolated, with pseudo-stratification and/or papillary proliferation
What is the role of progesterone in infection of the uterus in dogs?
- Progesterone causes increased susceptibility to infection of the uterus in the dog
- Progesterone stimulates glandular secretion and endometrial growth (cystic endometrial hyperplasia)
- Cystic hyperplasia: increased production and accumulation of mucus – mucometra/hydrometra
- Closure of cervix
- Reduced tone and rhythmic contractions of myometrium
- Decreased recruitment of neutrophils and reduced phagocytosis
- Secretion of progesterone-induced immunosuppressants
- Bacterial overgrowth is likely to follow
What circulatory disturbances can occur in the vagina and vulva?
Swelling -> physiological (may be normal)
What is vulvitis/vaginitis ?
- Inflammation of the vulva or vagina
- Can be as a result of bacterial, viral or protozoal infection
What does leiomyoma/sarcoma look like?
It is a disorder of growth
What are transmissible venereal tumours?
Canine Transmissible Venereal Tumour
- Round cells: histiocytic origin is suspected
- Sheets of neoplastic cells, minimal stroma -> Large, monomorphic, large nucleus, nucleolus, indistinct cell outline, high mitotic rate
- Most common tumour of the penis of dogs
- Usually on external genitalia, but extra-genital primaries possible
- Multiple or single, a few-millimeters to 10 cm diameter
- Metastasis possible
- Regression and recovery usual with infiltration of T lymphocytes and other inflammatory cells
What disorders of growth can occur in the vagina and the vulva?
- Leiomyoma/sarcoma
- Venereal disease
- Fibropapilloma
- Papilloma
- squamous cell carcinoma
- lymphosarcoma
