Prevalence, diagnosis, treatment outcomes and immunohistochemical characterization of neoplastic disorders in reptiles presented at a veterinary teaching hospital: A cross-sectional study (2010-2023).

Neoplasms seem to be increasingly encountered in reptile medicine. The present study investigated the prevalence, diagnosis, treatment outcome and immunohistochemical characterization of neoplasms diagnosed in reptile patients presented at a veterinary teaching hospital between 2010 and 2023. In this cross-sectional study, we analyzed the clinical records of 12383 reptiles (2549 snakes, 3386 lizards, and 6448 chelonians). Within the study population, 7261 reptiles showed clinical signs and in 130 of these cases, a histological diagnosis of neoplasm was made. A total of 134 neoplasms were identified in 27 out of 3270 chelonians (0.83 %), 63 out of 2395 lizards (2.63 %), and 40 out of 1596 snakes (2.51 %). While dermal neoplasms (n = 59; 44 %) such as squamous and basal cell carcinoma, were the most common neoplasms in lizards and chelonians, snakes were most frequently diagnosed with alimentary tract neoplasms (n = 35; 26.1 %), particularly tubular adenocarcinomas. Integumentary, reproductive and oral neoplasms carried a good prognosis following complete surgical removal, in contrast to most other neoplasms, particularly those with malignant, multicentric, or metastatic features. The results of this study elucidate the diversity of neoplastic disorders that can be encountered in reptiles within a clinical setting. In addition, similarities and differences with previously published retrospective studies originating from specialty diagnostic services and species-specific predispositions were investigated. Although histological evaluation allowed the characterization and classification of a large number of the observed neoplasms, the application of appropriate immunohistochemical protocols was indispensable towards accurate identification of several neoplasms, particularly neoplasms originating from the hematopoietic system and soft tissue sarcomas.