Primary primitive neuroectodermal tumour in the orbit of a domestic shorthair cat (Felis catus)

A 13-year-old, domestic shorthair cat presented for evaluation of left-sided exophthalmos, epiphora and third eyelid elevation of approximately 4-month duration. Based on ophthalmic exam findings, a retrobulbar mass was suspected. Computed tomography of the head revealed a fluid to soft-tissue, non-contrast-enhancing mass caudoventral to the left globe. Based on these findings, a retrobulbar abscess was considered the most likely differential, while a neoplastic mass could not be completely excluded. The mass and left globe were surgically excised via a modified lateral orbitotomy and exenteration. Histopathology and special staining of the mass was consistent with an orbital primitive neuroectodermal tumour, while the globe was unremarkable.