Yelena V. Osipenko, DVM
Leningrad Zoological Park, St. Petersburg, Russia
Malignant tumors have been described in different orders of reptiles, including Crocodilia.1,3,4 Many reports are based on postmortem findings. Antemortem malignant neoplasia was found primarily in adult to geriatric crocodile patients.2 In our case, squamous cell carcinoma was diagnosed antemortem in a young, 3.5–4-year-old, male Nile crocodile.
This crocodile presented with a 1-month history of anorexia. According to the owner, the animal had ingested latex foreign objects before he stopped eating. Dehydration and anemia were identified on physical examination. Palpation revealed a foreign body approximately 1.5–2 cm in length in the crocodile’s stomach. The owner prohibited any additional diagnostics, including radiology. The foreign objects (parts of decorations from a terrarium) were removed by stomach lavage. Supportive therapy was initiated. During the next week, there was no improvement. Additional diagnostic methods were applied. Survey radiographs and then contrast radiographs revealed a stenosing process in the duodenum, which led to gastrointestinal obstruction. Gastroscopy was performed using a medical fibrogastroduodenoscope. Due to the crocodile’s anatomic features, fibrogastroscopy permitted us to visualize only the esophagus and corpus (cardiac region) of the stomach. Pars pilorica, pyloric sphincter, and duodenum were not visualized. Pathologic tissue was observed neither in the esophagus nor in the cardiac region of the stomach. The reason for the gastrointestinal obstruction was not determined by radiology or endoscopy. Thus, diagnostic celiotomy was performed. Diagnostic celiotomy permitted us to visualize tumors, which were causing the gastrointestinal obstruction. Multiple tumors (3–7 mm in diameter) were visualized along the entire length of the small and large intestine. Multiple metastases to the liver, pancreas, and kidneys were identified. Histologic examination revealed a squamous cell carcinoma. Invasive growth and polymorphous cells were observed. High mitotic index suggested a high-order malignancy. When histologic examination results were obtained, the patient was humanely euthanatized.
Malignant tumors have been diagnosed in reptiles at the Leningrad zoo on rare occasions (less than 1% of annual morbidity and mortality). According to some reviews, neoplasia is diagnosed less often in Crocodilia than in other orders of reptiles.5 However, according to our experience, neoplasia should always be included in differential diagnosis even in very young crocodile patients.
I’d like to thank Svetlana I. Litkina, PhD, professor of radiology department at Military Medical Academy, St. Petersburg, for her help in taking x-rays and for interpreting the results. I’d also like to thank Dmitrii E. Mazko, Professor, PhD, Chief of the Department of Pathomorphology at Oncological Institute named after N.N. Petrov, for histological evaluation of the tumor.
1. Vasiliev D.B. 1999. Turtles. Maintenance, Diseases and Treatment. Moscow: Aquarium. Pp. 237–240. (VIN editor: This book is in Russian).
2. Frye F.L. 1991. Biomedical and Surgical Aspects of Captive Reptile Husbandry. Krieger Publishing Company, Malabar, FL. Vol. 2. Pp. 576–610.
3. Janert, B. 1998. A fibrosarcoma in a Siamese crocodile (Crocodylus siamensis). J. Zoo Wildl. Med. 29(1):72–77.
4. Mader, D.R. 1996. Reptile Medicine and Surgery. W.B. Saunders. Pp. 125–139.
5. Sykes, J.M., and J.G. Trupkiewicz. 2004. 101-year review of reptilian neoplasia at the Philadelphia Zoological Park. Proc. Am. Assoc. Zoo Vet. Annu. Meet. Pp. 92–94.