Metastasizing dysgerminoma in an inland bearded dragon (Pogona vitticeps)

Malignant dysgerminomas are infrequently reported ovarian neoplasms in animals, especially in exotic pets (non-traditional companion animals [NTCAs]). In the few published case reports on reptilian species, examples are primarily postmortem without antemortem (clinical) assessment.

An adult, 13-year-old, spayed female inland bearded dragon (Pogona vitticeps) presented with lethargy, a right-sided head tilt, unilateral exophthalmos and ventrotemporal strabismus on the right eye. On examination, a palpable mass (approximately 3.5 cm in diameter) was detected within the mid coelomic cavity. Computed tomography revealed a retrobulbar swelling and lytic bone lesions affecting the right frontal bone and several vertebrae (T11, T13, and T14). Multiple nodules of soft tissue opacity were also detected within the lungs, liver, and coelomic fat bodies. Haematology revealed leukocytosis with heterophilia and toxic granulation of heterophils. On the basis of these results, differential diagnoses included disseminated abscesses, granulomas (e.g., due to mycobacteriosis) and neoplasms. The lizard was subsequently euthanized due to end-stage disease and a poor prognosis. Postmortem gross examination and histopathology revealed a primary ovarian dysgerminoma with evidence of widespread metastasis as well as localized tissue destruction affecting the right retrobulbar space and frontal bone, the spinal column, the lungs, the liver, and both coelomic fat bodies.

This report describes a case of malignant dysgerminoma with widespread intraosseous and visceral metastases in a captive inland bearded dragon (Pogona vitticeps).