Neoplasia has been reported worldwide in amphibians, although there are few reports of intestinal and renal neoplasms, with the exception of the northern leopard frog (Rana pipiens) in which Rana herpesvirus-1-induced Lucké renal adenocarcinomas have been well described.1-3 Within a 3-month period, two marine toads (Bufo marinus) presented with prominent swellings in their pelvic areas. The first toad was diagnosed with a soft tissue mass within the pelvic inlet that was compressing the distal colon. Ultrasound revealed the mass to be well vascularized and intimately associated with the intestine. The mass was surgically resected; however, the toad was euthanatized 2 days later due to a severe colonic prolapse. Histopathology of the mass revealed a moderately well-differentiated transmural adenocarcinoma of the intestine, with no evidence of intranuclear inclusions. The second toad presented with a marked circumferentially swollen cloaca. Ultrasonography revealed a highly vascular soft tissue mass with scattered small cystic areas and intermingled wisps of hyperechogenic densities. Despite supportive therapy, the toad continued to lose weight and died approximately 2 weeks post presentation. On necropsy, in addition to the pericloacal mass, there were hemorrhagic foci noted in the kidneys. Histologically, multicentric adenocarcinoma of the kidneys and pericloacal tissue was diagnosed. Amphophilic to eosinophilic intranuclear inclusions were noted within the neoplastic renal parenchyma. The temporal spacing of the two cases, coupled with the intranuclear inclusions within the renal adenocarcinoma in the second toad, was suggestive of a viral etiology. Further testing, including electron microscopy, is underway to further define the nature of these neoplasms.
1. Davison, A.J., W. Sauerbier, A. Dolan, C. Addison, and R.G. McKinnell. 1999. Genomic studies of the Lucké tumor herpesvirus (RaHV-1). J. Cancer Res. Clin. Oncol. 125 (3–4):232–238.
2. Green, D.E., and J.C. Harshbarger. 2001. Spontaneous neoplasia in amphibia. In: Wright, K.M., and B.R. Whitaker (eds.). Amphibian Medicine and Captive Husbandry. Krieger Publishing Company. Florida. Pp. 335–400.
3. McKinnell R.G., and D.L. Carlson. 1997. Lucké renal adenocarcinoma, an anuran neoplasm: studies at the interface of pathology, virology, and differentiation competence. J. Cell Physiol. 173(2):115–118.