Anal or anorectal papilloma
Esther van Praag Ph.D.
Warning: this file contains pictures that may be distressing for
people
Small reddish excrescences sometimes protrude from the
anus of rabbits. Their origin is not well-understood; they are not associated
to the papilloma viruses causing oral or cutaneous papilloma
(Shope papilloma virus).
The cauliflower-like tumors arise at the mucocutaneous
junction of the rectum and the anus. The tumors are well differentiated and
benign. They bleed profusely when damaged.
Clinical signs and diagnosis
The presence of rectal or anal papilloma is a cause of
discomfort. They can, furthermore, lead to persistent, ineffectual spasms of
the rectum with inability to defecate (fecal tenesmus). This can lead to
misdiagnosis of stasis or inflammation of the intestine (colitis).
Treatment
Spontaneous regression of the anorectal papilloma is possible. Surgical removal of the
tumor remains, however, the treatment of choice as anal papilloma tumors are
the result of pre-malignant transformations of squamous columnar cells of the
anal or rectal mucosa. Ablative methods include classical surgical excision
or destruction by laser, electrodissecation or liquid nitrogen. If the growth
is located in the rectum, it can be accessed by everting
the rectum through the anus (”pull-out technique”). It is important to remove
the papilloma fully, including the basis to avoid recurrence. The tumor can
be sent to a specialized laboratory for hystopathologic
analysis. If the tumor
is invasive or presents cancerous characteristics, it should be excised with
the widest margin possible. Post-surgical care includes the
administration of NSAID’s analgesics to reduce the inflammation of tissues
and to control pain, and a diet rich in fiber. Prognosis is good.
AcknowledgementThanks are due to Akira
Yamanouchi, for the permission to use the papilloma pictures from VEIN (Veterinary Exotic Information
Network). Further Reading
Bourne D. Organisation Wildlife Information Network.
http://www.wildlifeinformation.org/ Harcourt-Brown, F. Textbook of Rabbit Medicine. Publisher Reed
Educational and Professional Publishing Ltd, Oxford, UK. 2002 Manning, P.J., Ringler, D.H. &
Newcomer, C.E. The Biology of the Laboratory Rabbit - Second Edition.
Publisher Academic Press Limited, 24-28 Oval Rd, London, UK. 1994 Quesenberry,
K.E. & Carpenter J.W. Ferrets, Rabbits and Rodents - Clinical Medicine
and Surgery. 2nd Edition. Publisher WB Saunders, Philadelphia, Pennsylvania,
USA. 2004 |
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