Cutaneous and Gastric Papillomatosis in a Pet Siberian Hamster ( Phodopus sungorus )

A Siberian hamster with multiple papillomatous lesions in the skin and gastrointestinal mucosa was evaluated using multiple diagnostic tests. Tissues collected from this hamster were examined through macroscopic, microscopic, immunohistochemical, and ultrastructural techniques. These multifocal papillomas were associated with a cutaneous basal cell carcinoma, sebaceous adenomas, sebaceus epitheliomas and demodicosis. Large amphophilic intranuclear inclusions were detected in keratinocytes and epithelial cells of both cutaneous and gastrointestinal papillomas. The intranuclear inclusions were strongly positive by immunohistochemistry for a papillomavirus (PV) structural antigen. Electronic-dense hexagonal viral particles 30 nm in diameter were observed within the nuclei of keratinocytes and gastrointestinal tract epithelial cells by transmission electron microscopy. No viral DNA was detected with polymerase chain reaction specific hamster or broad range PV primers. This report describes noninduced multicentric papillomatosis involving the gastric mucosa and gastroduodenal junction, which may have been the result of a new PV-type infection.