Retrospective review of neoplasms of captive lizards in the United Kingdom

Background Neoplasia has historically been regarded as an unusual occurrence in reptiles. The aim of the present study was to evaluate the prevalence of neoplasms in routine diagnostic samples submitted to a specialist exotic animal laboratory. Methods Over a 10-year period, 690 lizard samples were submitted for histopathological or cytopathological examination by Royal College of Veterinary Surgeons specialists in Veterinary Pathology (Zoo and Wildlife). Records were reviewed retrospectively and non-neoplastic diagnoses excluded from further analysis. Results 158 neoplasms were diagnosed in 149 lizards, with 22.9% of submissions resulting in a diagnosis of neoplasia. The skin was the most commonly affected organ, and squamous cell carcinomas were the most common neoplasms identified (17.7% of all neoplastic diagnoses). Bearded dragons and panther chameleons had a statistically significant higher proportion of neoplasia diagnosis than the lizard population as a whole, and geckos had a statistically significantly lower proportion. Several neoplasms identified in this study have not been previously reported in lizards, including a testicular Sertoli cell tumour, testicular granulosa cell tumour, splenic haemangiosarcoma, gastric adenocarcinoma and basal cell carcinoma. Conclusion The results suggest that the prevalence of neoplasia in captive lizards may be higher than previously reported, and that there is variation in prevalence between different lizard species and families. It is unclear whether these differences relate to genetic or management factors.