DISEASE SUMMARY PAGE

Endometrial Adenocarcinoma and other Uterine Neoplasia in Lagomorphs

Click here for full page view with caption. Disseminated uterine adenocarcinoma Click here for full page view with caption. Uterine adenocarcinoma in a rabbit doe. Uterine adenocarcinoma. Click here for full page view with caption Bloody vaginal discharge. Click here for full page view with caption

Summary Information
Diseases / List of Miscellaneous / Metabolic / Multifactorial Diseases / Disease summary
Alternative Names  
Disease Agents
  • Possible genetic factor, since some breeds are much more prone to development of endmetrial adenocarcinoma than are others. (J34.24.w3)
  • In one study, it was noted that some genetic lines of rabbits appeared to be more prone to uterine adenocarcinoma. (J494.67.w1)
  • Lepus europaeus - Brown hares in Australia, uterine abnormalities, including uterine neoplasias, were seen in older hares exposed to oestrogens in certain crops. (J1.40.w10)
Infectious Agent(s) --
Non-infectious Agent(s) --
Physical Agent(s) --
General Description Endometrial adenocarcinoma is the most common neoplasia seen in domestic rabbits. (B601.9.w9, B614.12.w12, J27.64.w4, J213.5.w1, J213.7.w1)
  • The second most common uterine tumour is adenoma; leiomyoma and leiomyosarcoma also occur, sometimes concurrently with adenocarcinoma. (B601.9.w9, B602.18.w18, J27.64.w4, J27.69.w2, J213.5.w1)
  • Adenocarcinoma extending into a leiomyoma has been described. (J27.69.w2)
Clinical signs
  • Early signs in breeding does: 
    • Reduced reproductive success, with infertility, resorption, stillbirths, fetal retention after the normal gestation period, smaller litter size (B601.9.w9, B602.18.w18, B614.12.w12, J34.24.w3, J213.5.w1, J213.7.w1, J494.67.w1), also extrauterine pregnancy (see: Extrauterine Pregnancy in Rabbits)) and sometimes maternal neglect. (J494.67.w1)
  • Early signs in pet rabbits:
    • Bloody vaginal discharge, which may be recognised as vulval bleeding or seen as haematuria. (B601.9.w9, B602.18.w18, J27.64.w4, J27.69.w2, J213.5.w1, J213.7.w1)
    • Particularly blood in the urine at the end of urination. (B602.18.w18)
  • Often cystic mammary glands. (B602.18.w18, B602.18.w18, J494.67.w1)
    • This may progress to neoplasia. (J494.67.w1)
  • Aggression. (J34.24.w3)
  • Weight loss. (J213.5.w1)
  • Pendulous abdomen (ascites). (B601.9.w9, B602.18.w18, J213.5.w1, J213.7.w1)
  • Partial urethral obstruction. (B601.9.w9)
  • Sometimes anaemia. (B601.9.w9)
  • Does may show signs similar to imminent parturition - pulling fur to make a nest, behavioural changes and swelling of the mammary glands. (J494.67.w1)
  • Later stages:
Pathology
  • Uterine adenocarcinomas arise from the glandular epithelium of the uterine mucous membrane. They retain an adenomatous structure. Very early growths may appear as nodular thickenings; slightly later growths, from 2 mm diameter, are often pedunculated. Usually they affect both uterine horns. They are found on the mucosal folds adjacent to the mesometrial insertion. Covered with normal epithelium, they have a smooth, glistening surface. Usually there are several, of similar size, spaced through both horns. Sometimes there is a single large mass, usually close to a fallopian tube. Older tumours may extend deep into the myometrium. Occasionally, growths appear as sausage-shaped masses in the uterine lumen, each attached by a thin stalk at its base. Tumours may replace most of the endometrium and myometrium. Tumours may necrose and slough and be passed out through the vagina. Histologically, uterine adenocarcinomas are seen as glandular elements, arranged atypically, in a variable stroma. More advanced tumours are often necrotic both centrally and along their free margin. Metastases usually are multiple and widespread in various organs. They have been found in all abdominal and thoracic organs, also in the thyroid and femur. There may be small miliary nodules on serosal surfaces and larger masses in the parenchyma of organs. Local spread also can be seen. (J494.67.w1)
Diagnosis
  • Palpation of abdominal mass(es), uterine nodules or a firm, irregular uterus. (B601.9.w9, B602.18.w18, B614.12.w12, J27.64.w4, J27.69.w2, J34.24.w3, J213.5.w1, J213.7.w1, J494.67.w1)
    • Size of nodules may increase from 1 cm to 5 cm in about six months. (B614.12.w12, J494.67.w1)
    • Nodules may remain static in size for some time, and occasionally may decrease in size - often just before metastases become evident. (J494.67.w1)
  • Radiography/ultrasonography will detect a uterine mass or masses; often multiple and affecting both horns. (B601.9.w9, B602.18.w18, J27.64.w4, J34.24.w3, J213.5.w1, J213.7.w1)
    • Note: Pulmonary radiographs should be taken to check for pulmonary metastases. (B602.18.w18, J34.24.w3)
  • An ultrasound-guided fine needle aspirate (FNA) may be taken for cytological examination for a definitive diagnosis. (B601.9.w9)
  • Laparotomy: Uterus enlarged and discoloured with nodules of varying sizes in one/both horns. (B600.14.w14, B602.18.w18, J213.7.w1)
    • Check thoroughly for local metastases. 
Treatment
  • Ovariohysterectomy. (B601.9.w9, B602.18.w18, J34.24.w3, J213.5.w1, J213.7.w1) 
    • See: Ovariohysterectomy of Rabbits
    • Good prognosis if restricted to the uterus. (B602.18.w18, J34.24.w3, J213.5.w1, J213.7.w1)
    • Poor prognosis if local or haematogenous spread has occurred at the time of surgery. (J34.24.w3)
      • Early local spread may not be visible at laparotomy, therefore the rabbit should be followed-up for two years after ovariohysterectomy (examinations every three months) , with a guarded prognosis during this period. (B601.9.w9, B602.18.w18)
      • Chemotherapy is not successful for uterine adenocarcinoma in rabbits. (B601.9.w9)
      • Leiomyomas are more common than leiomyosarcomas, but the latter may metastasize. (B614.12.w12)
Further Information Usually seen as a slowly progressive condition. Local spread occurs to the myometrium and into the peritoneal cavity; haematogenous spread occurs later (within a few years) resulting in metastases in the lungs, liver, brain and bones. (B600.14.w14, B602.18.w18, J213.5.w1); The disease usually progresses over 12-24 months. (J34.24.w3) In one study of over 80 cases of uterine adenocarcinoma, the time from tumour detection to death was 5-20 months, average 12 months, but with 14-29 months, average 19 months, from the first signs of reproductive disturbance to death; metastasis occurred in all individuals with tumours present for more than a year. (J494.67.w1)
Susceptibility/Transmission
  • More common in some breeds, e.g. Tan, French silver, Havana, Dutch rabbits. (B602.18.w18, J213.5.w1)
  • Rare in Polish, Rex and Belgian rabbits. (J34.24.w3)
  • In one study, uterine adenocarcinoma was seen in "Beveren, Dutch, English, Himalayan, Havana, Marten, Polish, Sable, Tan and Rexbreed, but not in members of the Belgian, Chinchilla or Silver breeds." (J494.67.w1)
  • Increased incidence in older does, reaching 50-80% in some breeds for individuals over three years of age. (J34.24.w3, J213.7.w1)
    • In one study, uterine neoplasia was seen in does of two years and two months to seven years and six months of age, peaking at 4-5 years. (J27.64.w4)
    • In a study of more than 80 cases in one laboratory colony, uterine adenocarcinoma never occurred in does younger than two years; there were 20% with onset in their third year, 44% with onset in their fourth year, 15% onset in their fifth year, 9% in their sixth year and 1% in their seventh year. The average age at the time the tumour was found was 45 months. (J494.67.w1)
    • May reach an incidence of 60% by four years of age. (B600.14.w14)
  • Incidence does not appear to be affected by whether or not the doe has bred. (B614.12.w12, J213.7.w1)
  • Note: Neoplasms are found much less frequently in wild lagomophs than in domestic rabbits. In general, few free-living lagomorphs survive to the age at which most neoplasms are likely to develop; neoplasia may therefore be more likely when these species are maintained in captivity and have longer live spans. (J351.41.w1)
    • Vaginal adenocarcinoma, extending to include the cervix and part of the uterus, has been diagnosed in a captive-maintained four-year-old female varying hare Lepus americanus virginianus (Lepus americanus - Snowshoe hare). (J351.41.w1)
    • In 245 wild Lepus europaeus - Brown hares in Australia, a uterine leiomyoma was found in one female, multiple polypous lipomas were noted in the uterine wall of another individual, and on the broad ligament. (J1.40.w10)
Prevention
  • Ovariohysterectomy will prevent the development of uterine neoplasia. (B602.18.w18, J34.24.w3, J213.5.w1, J213.7.w1) See: Ovariohysterectomy of Rabbits
  • Examine intact rabbit does over three years of age twice a year to allow early detection and treatment. (B602.18.w18, J34.24.w3)
Associated Techniques
Host taxa groups /species
Disease Author Debra Bourne MA VetMB PhD MRCVS (V.w5)
Referees Aidan Raftery MVB CertZooMed CBiol MIBiol MRCVS (V.w122)

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