DISEASE SUMMARY PAGE

Skin and Connective Tissue Neoplasia in Lagomorphs

Basal cell carcinoma. Click here for full page view with caption.

Summary Information
Diseases / List of Miscellaneous / Metabolic / Multifactorial Diseases / Disease summary
Alternative Names Skin and connective tissue tumours
Disease Agents Various viral agents see: 
Infectious Agent(s) --
Non-infectious Agent(s) --
Physical Agent(s) --
General Description

 

Viral skin tumours in lagomorphs

Primary skin and connective tissue tumours
In Oryctolagus cuniculus domesticus:
  • Basal cell carcinoma (trichoblastoma or adenoma)
    • In one study, this was the most common skin neoplasm of rabbits. (B601.13.w13)
    • In a report on two cases of this type of tumour, both tumours were benign and seen in rabbits older than four years of age. In one of the cases, there were two small (two by one centimetre) pedunculated adenomas that were of multicentric origin and were projecting above the skin on the right abdominal dorsum. Histologically the tumours are similar to that described in other species, especially canine, and included "hyperkeratotic stratified squamous epithelium overlying clumps or n[e]sts of epithelial (basilar) cells in a coarse, collagenous, often acellular stroma". (B614.12.w12)
  • Squamous cell carcinoma
    • These tumours can occur anywhere on the body. (B614.12.w12)
    • In a report on six separate cases of natural occurrence of this tumour in Oryctolagus cuniculus domesticus, only one of the tumours was metastatic. (B614.12.w12)
  • Trichoepithelioma
  • Malignant melanoma
  • Lipomas 
  • Sebaceous cell carcinoma

(B600.9.w9, B601.13.w13, B602.19.w19, B606.4.w4, B608.21.w21, B614.12.w12, B615.6.w6, J213.4.w4)

  • Papillomas (B600.9.w9, B601.13.w13, B608.21.w21)
    • Clinical signs: 
      • Small cauliflower-like, friable tumours that bleed easily. (B600.9.w9)
    • Distribution: 
      • Rectoanal junction. These tumours develop on the epithelium of the mucosal junction and may be found protruding from the anus. (B600.9.w9)
    • Treatment: 
      • Generally the tumours do not cause a problem and will eventually resolve with time. However, in some cases, surgical removal is necessary to prevent recurrence, ensure the base of the tumour is removed. (B600.9.w9, B615.6.w6)
    • Transmission:
      • It is not known if this tumour is transmissible. 
      • "Transmission experiments with tumour tissue from two rectoanal papillomas in laboratory rabbits were unsuccessful. The papillomas were well differentiated and benign and inclusion bodies could not be demonstrated." (B600.9.w9)
  • Cutaneous lymphoma
    • This may be an epitheliotropic lymphoma of T-cell origin (which may metastasise to involve visceral organs), or cutaneous involvement of a visceral lymphoma. (B602.21.w21b)
    • Clinically, one or multiple subcutaneous masses may be noted. Non-pruritic alopecia, and alopecia with erythema and haemorrhagic crusts, have also been noted. (B602.21.w21b)
In Lepus and Sylvilagus:
It is generally thought that there is a very low incidence of all types of neoplasms in wildlife. Numerous factors contribute to this observation including:
  • wild rabbits and hares generally don't survive into old age;
  • most animals that die naturally are not available for post mortem;
  • ill and and tumour-bearing rabbits are rarely seen by hunters;
  • these species have not been successfully domesticated so longitudinal lifetime observations of them have not been possible.

In Sylvilagus there has been a case of a lipoma reported and in Lepus there has been a case of a naturally occurring fibroma.

(B614.12.w12)


Secondary skin and connective tissue tumours
In Oryctolagus cuniculus domesticus:
  • Uterine adenocarcinoma metatases. (B602.19.w19)
    • Multiple hard skin nodules. (B600.9.w9)
  • Cutaneous fibrosarcoma (B602.19.w19)
    • Occurs either as a localised or generalised skin condition. (B600.9.w9)
  • Connective tissue tumours (B602.19.w19, J213.4.w4)
    • Collagenous naevus
      • A benign focal accumulation of collagen that presents as painless, solitary or multiple, papules or nodules that are dome-shaped and possibly alopecic. (B600.9.w9)
  • Lymphosarcoma / cutaneous lymphoma (B600.9.w9, B601.13.w13, B604.5.w5)
    • This condition has been reported in domestic rabbits from seven weeks to nine and a half years of age. Most of these affected rabbits had early involvement of internal organs (e.g. lungs and lymph nodes) and systemic disease. (B602.19.w19, B608.21.w21b)
    • Cutaneous lesions consisted of subcutaneous mass or masses, or areas of non-pruritic alopecia, or alopecia with erythema and haemorrhagic crusts. (B602.21.w21b)
      • Bilateral blepharitis was the presenting sign in one rabbit. (B602.21.w21b)
        (B602.19.w19, B602.21.w21b B608.21.w21)
    • Histologically, the lymphomas were CD3+ and epitheliotropic. (B608.21.w21)
    • One rabbit was treated with oral administration of isotretinoin and interferon-α. (B608.21.w21)
  • Osteosarcoma (B600.9.w9, B608.21.w21)

 

Further Information
Differential diagnoses of skin nodules
  • Small abscesses
    • These may be the result of injections, fight wounds, lymphatic or haematogenous spread from elsewhere in the body, surgical excisions. (B600.9.w9)
    • Surgical excision is often curative. (B600.9.w9)
    • See: Abscessation
  • Atypical myxomatosis (B600.9.w9)
Diagnosis
  • Histopathology on biopsy or excision samples. (B600.9.w9, B602.19.w19, B602.21.w21b J213.4.w4)
    • To biopsy a lesion in the conscious rabbit, use a topical preparation containing Prilocaine and Lidocaine (EMLA cream) as a local anaesthetic. (B600.9.w9)
Treatment
  • Primary skin tumours in the rabbit are usually slow to metastasise and so surgical excision is curative. (B606.4.w4)
  • Surgical excision or debulking. (B602.19.w19)
  • Chemotherapy- unsuccessful in treatment of cutaneous lymphoma in rabbits. (B602.19.w19)
Associated Techniques
Host taxa groups /species
Disease Author Nikki Fox BVSc MRCVS (V.w103)
Referees Anna Meredith MA VetMB CertLAS DZooMed (Mammalian) MRCVS (V.w128); Richard Saunders BVSc BSc CertZooMed MRCVS (V.w121)

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