A 7-year-old female iguana with a 1-year history of inappetence, lethargy, heterophilia (27,600 mm3), and elevated phosphorus (>16.1 mg/dl) and uric acid (9.8 mg/dl) levels was presented for progression of clinical signs. Laboratory results revealed a WBC of 15,000 mm3 and phosphorus, CPK, and uric acid levels of 22.6 mg/dl, 6390 I/L and 13.9 mg/dl, respectively. Radiographs were unremarkable. The animal died shortly after admission. Gross necropsy showed enlarged pale kidneys and a mottled tan/brown liver. Sections of liver, kidney and bone marrow were submitted for histologic evaluation.
The bone marrow contained a highly cellular infiltrative mass that had effaced normal histologic architecture. The mass was composed of sheets of round cells that had basophilic, vesicular, usually eccentric nuclei; scant pale basophilic cytoplasm and distinct cell borders. Mitoses (1–3/hpf) were observed. Similar neoplastic infiltrates were effacing 90% and 75% of the kidney and liver histologic architecture, respectively. Additionally, only ghosts of glomeruli were observed in the kidney and the scattered remaining renal tubules were dilated.
These findings are consistent with disseminated immunoblastic leukemia. Similar tumors have been reported in a Savannah monitor,4 giant snake,1 rhinoceros viper and Eastern and California king snakes.3,2 Intranuclear virus-like inclusions were observed in tumor cells in the California king snakes.2 Electron microscopic examination of tumor cells in this iguana did not reveal any structures known to be consistent with virus particles.
1. Frank, W. and A. Schepky. 1969. Metastasizing lymphosarcoma in a giant snake, Eunectes murinus. Pathol. Vet. 6(5):437–43.
2. Jacobson, E. R., J. C. Seely, and M. N. Novilla. 1980. Lymphosarcoma associated with virus-like intranuclear inclusions in a California king snake (Colubridae: Lampropeltis). J. Natl. Cancer Inst. 65(3):577–83.
3. Jacobson E., M. B. Calderwood, T. W. French, W. Iverson, D. Page and B. Raphael. 1981. Lymphosarcoma in an Eastern king snake and a rhinoceros viper. J. Am. Vet. Med. Assoc. 179(11):1231–5.
4. Schultze A. E., G. L. Mason and V. L. Clyde. 1999. Lymphosarcoma with leukemic blood profile in a Savannah monitor lizard (Varanus exanthematicus). J. Zoo Wildl. Med. 30(1):158–64.