Osteosarcoma in a woma python (Aspidites ramsayi)

Survey of Post-Cranial Skeletal Pathology in Snakes

Previous reports on skeletal pathology in captive snakes did not clarify the relationship of lesions to captive or free-ranging status. In this study, post-cranial skeletons from 7,950 captive and free-ranging snakes in nine of the major North American collections were examined macroscopically, microscopically and radiologically for the presence of pathology. Micro-computerized tomography was performed on two skeletons on which surface microscopy failed to provide a definitive diagnosis. Osteomyelitis was identified in the vertebrae of 24 snakes and spondyloarthropathy in one snake. Neoplasia or congenital anomalies were not found. Osteomyelitis was four times as common in Viperidae than in Colubridae and twice as common as in Boidae, independent of captive or free-ranging status. A lytic lesion in the vertebrae of one snake was suggestive of fungal disease. The progression of bone lesions was greater in captive snakes, but the prevalence was independent of captive or free-ranging status. The results of this study indicate that bone alterations, previously proposed as neoplastic disease, in archival snake skeletons were most likely of infectious aetiology, and establish macroscopic examination as a useful technique for characterizing skeletal pathology in snakes.

Possible osteosarcoma reported from a new world elapid snake and review of reptilian bony tumors

Cancer chiefly occurs in vertebrates. Rare in amphibians, and perhaps common in reptiles, various neoplasms and malignant cancers have been reported with erratic frequency by museums, paleontologists, veterinarians, and pet hobbyists. Unsurprisingly, most herpetofaunal diversity has never been systematically surveyed for the presence of neoplasms owing to the extreme rarity or obscurity of many species. Museum collections can fill these gaps in knowledge, especially when researchers use non-destructive techniques. In this study, we used X-ray computed tomography (CT) to discover and characterize a possible osteosarcoma of the spine in a rare South American coralsnake, Micrurus ancoralis. Two spinal vertebrae were completely fused and adjacent vertebrae showed evidence of corruption. The fused vertebrae contained a hollow inner network thought to be vascular tissue. We also review previous reports of neoplasms in the Elapidae and all bony neoplasms in non-avian reptiles. The rarely reported technique of X-ray CT for tumor discovery could greatly improve our understanding of the species diversity and perhaps underlying causes of neoplasia.

The Use of Self-Inflating Hygroscopic Tissue Expanders to Facilitate Osteosarcoma Removal in a Massasauga Rattlesnake (Sistrurus catenatus)

A 0.34 kg adult female Massasauga rattlesnake (Sistrurus catenatus) was presented for evaluation of a subcutaneous mass affecting the ventral scales. The mass was diagnosed as a sarcoma via punch biopsy with no evidence of metastasis on diagnostic imaging. Surgical margins of 1-2 cm were planned to achieve complete excision of the neoplasm. A technique for tissue expansion was employed due to concerns regarding the ability to close the surgical site without excess tension or dehiscence. Two 27 mm diameter × 5 mm hygroscopic self-inflating tissue expanders were placed subcutaneously under the lateral scales adjacent to the mass. Maximum skin expansion occurred over a four-week period, and no direct negative effects were noted. Excision of the primary mass was performed routinely five weeks after implant placement. Primary closure of the defect was achieved with minimal tension by incorporating the expanded skin. While the surgery was successful with no evidence of metastasis, the snake died of sepsis two weeks postoperatively. This is the first report of the use of self-inflating hygroscopic tissue expanders to help close a surgical defect in a reptile.

Risk Factors for Development of Canine and Human Osteosarcoma: A Comparative Review

Osteosarcoma is the most common primary tumor of bone. Osteosarcomas are rare in humans, but occur more commonly in dogs. A comparative approach to studying osteosarcoma has highlighted many clinical and biologic aspects of the disease that are similar between dogs and humans; however, important species-specific differences are becoming increasingly recognized. In this review, we describe risk factors for the development of osteosarcoma in dogs and humans, including height and body size, genetics, and conditions that increase turnover of bone-forming cells, underscoring the concept that stochastic mutational events associated with cellular replication are likely to be the major molecular drivers of this disease. We also discuss adaptive, cancer-protective traits that have evolved in large, long-lived mammals, and how increasing size and longevity in the absence of natural selection can account for the elevated bone cancer risk in modern domestic dogs.

Orthopedics in Reptiles and Amphibians

Musculoskeletal disorders are a common cause for presentation of reptiles and amphibians to the veterinarian. A clinical approach to orthopedic cases starts with a thorough history and review of husbandry, and identification of any underlying or concomitant disease. Medical management is indicated for pathologic fractures. Traumatic fractures may require surgical intervention. Stabilization options include external coaptation and/or external and internal fixation. Special considerations must be given to shell fractures in chelonians. Many techniques used in mammalian practice can be applied to reptiles and amphibians, although some species may require prolonged healing times by comparison.

Orthopedic Diagnostic Imaging in Exotic Pets

Orthopedic diseases are a common problem in exotic pets. Diagnostic imaging modalities are more accessible and available in exotic animal veterinary medicine; the higher standards of care of the veterinary profession have progressed toward an increased offer of advanced imaging modalities. The literature on the use of diagnostic imaging modalities in orthopedic disease of exotic pets is scarce. This article discusses when to use the different diagnostic imaging techniques and reviews the imaging findings usually found in the most common orthopedic diseases in small mammal, avian, and reptile exotic pet species using different imaging modalities, especially radiography and computed tomography.

Oncology of Reptiles: Diseases, Diagnosis, and Treatment

Based on necropsy review, neoplasia in reptiles has a comparable frequency to that of mammals and birds. Reptile neoplasia is now more frequently diagnosed in clinical practice based on increased use of advanced diagnostic techniques and improvements in reptilian husbandry allowing greater longevity of these species. This article reviews the current literature on neoplasia in reptiles, and focuses on advanced diagnostics and therapeutic options for reptilian patientssuffering neoplastic disease. Although most applied clinical reptile oncology is translated from dog and cat oncology, considerations specific to reptilian patients commonly encountered in clinical practice (turtles, tortoises, snakes, and lizards) are presented.

[Bone tumours in lizards and snakes. A rare clinical finding]

OBJECTIVE

This article presents the pathological findings of 13 bone and cartilage tumours in lizards (n=8) and snakes (n=5) within the clinical context.

MATERIAL AND METHODS

Within a 12-year period (2001-2013), 13 cases of bone tumours in reptiles were diagnosed from 358 submitted tumour specimens. Pathological examination was performed on eight excisions, two biopsies, two amputates and four carcasses. Macroscopically, the samples displayed a light-coloured surface when cut and had a generally solid consistency. For the histological examination, representative specimens were decalcified when necessary, embedded in paraffin and stained using haematoxylin and eosin. Diagnosis was made based on the World Health Organisation classification for veterinary and human medicine.

RESULTS

Benign proliferations of the bone (ossifying fibroma [n=2], fibrous dysplasia [n=1]) as well as malignant cartilage (chondrosarcoma [n=2]) and bone tumours (fibroblastic osteosarcoma [n=2], small cell osteosarcoma [n=1]) were found on the head (n=5) and limbs (n=3) of various lizard species. In snakes only malignant cartilage neoplasms (chondrosarcoma [n=2], dedifferentiated chondrosarcoma [n=3]) of the spine were diagnosed. The histological appearance of the malignant tumours ranged from low to highly malignant differentiated aggregations of tumour cells, that produced varying amounts of osteoid or a hyaline matrix. Curative therapy was achieved in one ossifying fibroma by complete surgical removal and in two chondrosarcomas through amputation. No metastasis was observed in any of the four necropsies.

CONCLUSION AND CLINICAL RELEVANCE

Primary neoplasias of the bone are rare tumours in reptiles. Considering the information on therapeutic procedures and clinical course, the therapy of choice in lizards is complete surgical removal whereas in snakes reductive surgery may prolong the survival time.

Gastric adenocarcinoma in a diamond python (Morelia spilota spilota)

CASE REPORT

A 5-year-old captive male diamond python (Morelia spilota spilota) was presented with a 1-month history of regurgitation and anorexia and discrete coelomic distention. Physical examination revealed a firm, immobile mass at approximately two-thirds of the snout-vent length from the front of the head. Ultrasound-guided fine needle aspirate biopsy of the mass in the region of the stomach showed necrosis with bacterial infiltration and possibly neoplastic changes. A gastroscopy was conducted, but showed grossly normal gastric mucosa, confirmed by biopsy. On exploratory coeliotomy, it was confirmed the mass involved most of the stomach wall and occluded the gastric lumen. The mass was completely excised and based on histopathology, a diagnosis of gastric adenocarcinoma was made. The snake was found dead 12 h postoperatively, but no specific cause of death was found on postmortem examination.

CONCLUSION

Most cases of adenocarcinoma in snakes go undiagnosed. This case report illustrates that the architecture of gastric masses may lead to false-negative gastric biopsy results in snakes with neoplasia.