Cutaneous squamous cell carcinomas in domestic rabbits (Oryctolagus cuniculus): 39 cases (1998-2019)

Background: Domestic rabbits (Oryctolagus cuniculi) can develop a variety of cutaneous neoplasms, including squamous cell carcinoma (SCC). A detailed review of gross and microscopic pathology and response to treatment of spontaneously arising SCCs in domestic rabbits has not been published.Methods: A retrospective survey study of the clinical characteristics and response to treatment in 39 cases of spontaneous SCC in pet rabbits was performed in an attempt to better characterize the typical presentation, prognosis, and therapeutic response of SCCs in domestic rabbits. Sixteen of these cases were also selected for papillomavirus testing using a generic polymerase chain reaction.Results: SCC was identified in rabbits between 2 and 10 years of age, with a median age of 7 years. The neoplasm has a predilection for ears and feet and the conventional subtype is most commonly diagnosed microscopically. Lighter colored rabbits may be predisposed to developing SCC. The majority of cases examined were found in rabbits housed primarily indoors. Only one SCC tested positive for papillomavirus and was located in the oral cavity. Sequencing of the detected PCR product detected 98.75% similarity to human papillomavirus type 120. The significance of this virus for tumorigenesis is unknown.Conclusions and clinical relevance: Aggressive surgical resection provided the most successful therapeutic option and proved curative in 12 of 23 rabbits. Papillomavirus likely does not play a major role in the development of spontaneous SCCs in pet rabbits. More research is needed to investigate the use of adjunctive therapies in treatment of this neoplasm in pet rabbits.