Orbital liposarcoma in a dog : a case report

Purpose: To report a case of primary canine orbital liposarcoma. Methods: A middle aged female-spayed mongrel dog, from the public kennel, was referred with a history of swelling and opacity of the left eye that had worsened over the past 2 months. Results: No abnormalities were detected on general clinical examination. Mouth opening was not painful and examination of the oral cavity was unremarkable. Ophthalmic examination showed severe left exophthalmos with reduced globe retropulsion and central exposure keratitis. Corneal opacification prevented posterior segment examination. An orbital space occupying lesion was diagnosed, further diagnostic tests were declined by the kennel handler due to financial constraints. Enucleation was performed. A retrobulbar, multilobulated mass, 2.5 9 3 9 3 cm, was excised along with the globe and formalin- fixed. Histologically, the mass was composed of dense sheets of large polygonal cells separated by thin fibrous stroma. Cells have well defined borders, abundant vacuolated cytoplasm and small, peripheral nuclei. Cell atypia was mild, mitoses <1/10 HPF. Immunohistochemically neoplastic cells were negative for pancytokeratin and desmin, positive for vimentin and S100; a well differentiated orbital liposarcoma was therefore diagnosed. The dog recovered uneventfully from surgery and no recurrence has been noted after 8 months. Conclusions: Liposarcoma is a common soft-tissue sarcoma but only rarely detected in the orbit. In men, its outcome is dependent on tumor dimension (<5 cm) and histologic subtype. In the present case neither recurrence nor signs of metastases were detected 8 months from diagnosis.