Cranial and intra-axial metastasis originating from a primary ovarian Dysgerminoma

Metastasizing dysgerminoma in an inland bearded dragon (Pogona vitticeps)

BACKGROUND

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.

PATIENT PRESENTATION

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.

CONCLUSIONS

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

Uncommon Metastasis of Ovarian Dysgerminoma: A Case Report and Review of the Literature

Ovarian malignant germ cell tumors (OMGCT) represent less than 10% of all ovarian tumors. Dysgerminoma is the most common malignant primitive germ cell tumor in young women, known for its curability and low propensity to invade and metastasize when diagnosed early. Herein, we report an unusual type of ovarian dysgerminoma (OD) metastasis with a brief review of the literature, lacking similar reported cases. To our knowledge, although there are several case reports of dysgerminoma metastases with variable anatomic location and presentation, vaginal metastasis has not been previously described. The local or systemic relapse together with local and distant metastasis is considered as an independent predictor of poor survival in patients with OD. In light of the absence of mutations status, our patient successfully responded to therapy. Currently, the patient remains in clinical remission. A specific follow-up plan is ongoing knowing that ovarian dysgerminomas tend to recur most often in the first 2–3 years after treatment.