Lymphosarcoma with leukemic blood profile in a Savannah monitor lizard (Varanus exanthematicus)

A 6-mo-old male Savannah monitor lizard (Varanus exanthematicus) was presented for lethargy and anorexia of 7 days duration. Physical examination revealed a slightly raised subcutaneous mass (1 cm diameter) in the left scapular area. Fine-needle aspiration cytology of the mass revealed a population of immature, pleomorphic lymphoid cells consistent with lymphosarcoma. A hemogram indicated marked leukocytosis (465,000 cells/microl) characterized by extreme lymphocytosis and many circulating lymphoid blast cells. The lizard was euthanized at the owner's request. Necropsy revealed severe hepatomegaly and multiple raised, ulcerated mural masses in the gastrointestinal tract. There were many raised, poorly demarcated tan foci in all the parenchymal organs. Histopathologic examination confirmed infiltration of all parenchymal organs by neoplastic lymphoid cells. Transmission electron microscopic examination failed to identify viruses within the neoplastic cells. A literature review revealed few reports of squamate leukemia and lymphosarcoma and none in Savannah monitor lizards.