1Potawatomi Zoo, South Bend, IN, USA; 2Akron Zoological Park, Akron, OH, USA; 3Zoo Miami, Miami, FL, USA; 4Diagnostic Center for Population and Animal Health, Michigan State University, Lansing, MI, USA; 5Northwest ZooPath, Monroe, WA, USA
Although once thought rare in reptiles, neoplastic diseases are now being recognized more frequently.1,2 However, endocrine neoplasms in reptiles are still rarely reported. We report multihormonal pancreatic islet cell carcinomas in three captive Komodo dragons (Varanus komodensis), a 15-year-old female, a 16-year-old male, and a 25-year-old male. Two of the three cases were noted at postmortem to have a grossly abnormal pancreas. Histologically, the tumors were comprised of nests and cords of well-differentiated neoplastic islet cells with scant amounts of eosinophilic cytoplasm and round, euchromatic nuclei, with rare mitoses. Infiltration by the islet cell tumor into the surrounding acinar tissue was observed in all cases, but no metastatic foci were seen. Multi-hormone expression was observed in all tumors, which were immunohistochemically strongly positive for glucagon and somatostatin and focally positive for polypeptide. Interestingly, somatostatin expression has been previously reported in a series of intestinal neuroendocrine carcinomas in bearded dragons.3 While the clinical impact of the islet cell carcinomas in the Komodo dragons is unknown, for animals presenting with weakness, lethargy, and poor appetite, pancreatic islet cell neoplasms should be considered as a differential.
The authors thank Species Survival Plan (SSP) advisors Don Boyer, Rick Haeffner, and Dr. Rob Coke for their support on this project.
1. Garner MM, Hernandez-Divers SM, Raymond JT. Reptile neoplasia: a retrospective study of case submissions to a specialty diagnostic service. Vet Clin North Am Exot Anim Pract. 2004;7(3):653–671.
2. Hernandez-Divers SM, Garner MM. Neoplasia of reptiles with an emphasis on lizards. Vet Clin North Am Exot Anim Pract. 2003;6(1):251–273.
3. Ritter JM, Garner MM, Chilton JA, Jacobson ER, Kuipel M. Gastric neuroendocrine carcinomas in bearded dragons (Pogona vitticeps). Vet Pathol. 2009;46(6):1109–1116.