Cutaneous and Subcutaneous Soft Tissue Tumours in Snakes: A Retrospective Study of 33 Cases

Urothelial carcinoma in a Russian tortoise (Testudohorsfieldii)

An adult female Russian tortoise (Testudo horsfieldii) was admitted to a veterinary clinic with a 1-week history of anorexia and lethargy. Physical examination revealed significant dehydration and generalized dysecdysis. Blood parameters were all within species-reported limits. Radiography revealed an increased amount of soft tissue opacity within the coelomic cavity and a distinct loss of serosal detail. A large cavitated mass was detected ultrasonographically in the right coelom and a tentative diagnosis of kidney pathology was made. Using computed tomography and magnetic resonance imaging, a partly mineralized heterogeneous mass was seen in the right coelom. After stabilization, a transplastron coeliotomy was performed. A 7 × 5 cm mass, including associated cysts, was removed. The tortoise died 8 h postoperatively and post-mortem examination revealed a urothelial carcinoma arising from the renal pelvis. To the authors' knowledge, this is the first report in a tortoise of urothelial carcinoma, which has rarely been reported in reptiles.

A Multi-Institutional Collaboration to Understand Neoplasia, Treatment and Survival of Snakes

This multi-institutional collaborative study of neoplasia in snakes reviewed medical records of snakes at each facility to determine species prevalence, survival, and methods of treatment. Complete species numbers of snakes were also collected at each facility. In total, 65 species, 133 snakes, and 149 unique neoplasias were included in this study. Affected species, age, sex, and their tumor prevalence, tumor type and location, metastasis, treatment, and survival data are reported. The highest species-specific tumor prevalence was in Common or Northern Watersnakes (Nerodia sipedon) (30.8%, n = 4 of 13), Eastern Diamond-Backed Rattlesnakes (Crotalus adamanteus) (26.3%, n = 5 of 19), and Timber rattlesnakes (Crotalus horridus) (22.7%, n = 5 of 22). Malignant tumors predominated (86.6%, n = 129 of 149) with soft tissue sarcomas being the most common (30.2%, n = 45 of 149). Snakes with malignant neoplasia, metastases, or indeterminate presence of metastases were statistically more likely to die from their neoplasms than snakes having either benign neoplasia or no diagnosed metastases (p < 0.05). Gender, taxonomic family, and species of those evaluated did not significantly affect the outcome of snakes with neoplasia. Only 27.1% (n = 36 of 133) of snakes received a reported form of treatment and, for those treated, surgical excision was the most common treatment modality. There was not a significant difference in outcome based on treatment; however, surgery and chemotherapy were associated with death from a cause other than their tumor.

Rhabdomyosarcoma on the Forelimb of a Common Musk Turtle (Sternotherus odoratus)

Malignant mesenchymal tumours are only rarely reported in turtles. In the present case, an 8-year-old female common musk turtle (Sternotherus odoratus) was presented with a solid, reddened, non-mobile mass on the right forelimb. The mass had a thin, membranous lining and a grey-white cut surface. Histological examination revealed a cell-rich, focally infiltrative neoplasm consisting of spindloid tumour cells arranged in bundles and streams. Rarely, indistinct cytoplasmic cross-striations were seen in the neoplastic cells. Transmission electron microscopy revealed cytoplasmic, disorganized muscle fibrils and haphazardly arranged, attenuated Z-lines in the neoplastic cells. The histological, histochemical and ultrastructural findings led to the diagnosis of a rhabdomyosarcoma. This is the first description of rhabdomyosarcoma in a freshwater turtle.

Occurrence of myxoma in a bearded dragon (Pogona vitticeps): Surgical and histopathological studies

Myxoma is a benign mesenchymal tumor of skin and soft connective tissues considered to be of fibroblastic origin. A female bearded dragon (Pogona vitticeps) with a raised mass on the left side of the body was referred to the Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran. The mass had become evident and grew more extensive within the previous 11-month period. The dragon was anesthetized with 5.00% isoflurane, and the mass was removed surgically. Tissue samples of the mass were fixed in 10.00% neutral buffered formalin, sectioned and stained with Hematoxylin and Eosin (H&E), Alcian blue (pH: 2.50), and periodic acid Schiff (PAS) staining techniques. The patient was administered meloxicam, lincomycin, and marbofloxacin. Histopathologically, the capsulated mass was composed of myxoid structure. Stellate-to-reticular cells distributed in a mucinous stroma containing few tiny blood vessels were seen. Myxoid cells displayed a PAS-positive cytoplasm. The myxomatous matrix was alcianophilic at the pH of 2.50. To our knowledge, this is the first report of surgery, treatment, and histopathological study of myxoma in a bearded dragon (P. vitticeps). The sutures were also removed 12 days after the operation. No new growth of the mass was observed three months following the surgical procedures.

A comprehensive diagnostic approach combining phylogenetic disease bracketing and CT imaging reveals osteomyelitis in a Tyrannosaurus rex

Traditional palaeontological techniques of disease characterisation are limited to the analysis of osseous fossils, requiring several lines of evidence to support diagnoses. This study presents a novel stepwise concept for comprehensive diagnosis of pathologies in fossils by computed tomography imaging for morphological assessment combined with likelihood estimation based on systematic phylogenetic disease bracketing. This approach was applied to characterise pathologies of the left fibula and fused caudal vertebrae of the non-avian dinosaur Tyrannosaurus rex. Initial morphological assessment narrowed the differential diagnosis to neoplasia or infection. Subsequent data review from phylogenetically closely related species at the clade level revealed neoplasia rates as low as 3.1% and 1.8%, while infectious-disease rates were 32.0% and 53.9% in extant dinosaurs (birds) and non-avian reptiles, respectively. Furthermore, the survey of literature revealed that within the phylogenetic disease bracket the oldest case of bone infection (osteomyelitis) was identified in the mandible of a 275-million-year-old captorhinid eureptile Labidosaurus. These findings demonstrate low probability of a neoplastic aetiology of the examined pathologies in the Tyrannosaurus rex and in turn, suggest that they correspond to multiple foci of osteomyelitis.

The occurrence of cancer in vertebrates: a mini review

Neoplasia is a multilevel condition caused by irregularities over the genome, which can lead to a fatal result. To fully understand this phenomenon, an evolutionary challenge has risen during the last decades, away from human limits, driving the scientific quest into the wild life. The study of wild vertebrate populations in their natural habitats has shown that cancer is rather prominent. Thus, the diversity of vertebrates reported with some form of neoplasia is quite scattered through a variety of habitats. However, some species constitute exceptions by exhibiting cancer-protective features, driven by certain loci in their DNA. It is obvious that from an evolutionary standpoint, the incidence of cancer in different taxa is nowadays studied by seeking for patterns and their roots. The main purpose of the evolutionary approach is no other than to answer a fundamental question: Could cancer be ultimately regarded as another evolutionary force conducive to the formation or shaping-up of species?

Cancer Prevalence and Etiology in Wild and Captive Animals

Neoplasia has been recorded in the vast majority of metazoans. The frequent occurrence of cancer in multicellular organisms suggests that neoplasia, similar to pathogens/parasites, may have a significant negative impact on host fitness in the wild. This is supported by the fact that wildlife cancers have recently been shown to result in significantly increased levels of mortality and concomitant reduction in fitness. By thorough searches of the available literature we provide a comprehensive and an updated list of cancer prevalence and etiology in the wild. We were, however, unable to find data on nontransmissible cancer prevalence in invertebrates and consequently this chapter focuses on cancer in wild vertebrates. Although single cases of cancer are frequently encountered in the wildlife, we were only able to retrieve robust data on cancer prevalence for 31 vertebrate species (12 fish, 3 amphibians, 2 reptiles, 2 birds, and 12 mammals). Cancer prevalence among these vertebrates ranged from as low as 0.2% observed in Canada geese (Branta canadensis) to more than 50% recorded in both Santa Catalina Island foxes (Urocyon littoralis catalinae) and Cape mountain zebras (Equus zebra zebra). The high prevalence recorded in some vertebrates strongly suggests that cancer in wildlife may indeed carry significant fitness costs. In spite of this, the low number of published comprehensive studies clearly shows that so far cancer in wildlife has received insufficient attention by biologists. We hope that this chapter will act as a catalyst for further studies focusing on the impact of cancer in wild animals. The chapter additionally compares cancer recorded in French zoological parks to those obtained at other zoological parks. Finally, we provide an updated list of cancer recorded as single cases in the wild, as well as in captive animals.