A rare retrobulbar and chiasmal meningioma in a dog

Abstract

A 14-year-old female Dachshund was referred to a veterinary hospital with a history and signalment of head pressing, compulsive walking, and right circling. At ophthalmologic examination, a mature cataract and absence of photomotor reflex in the right eye were observed. The neurological exam revealed multifocal encephalic signs. At necropsy, a conical solid tan mass was observed involving the right optic nerve throughout its extension to the optic chiasm. Histopathological findings confirmed a retrobulbar papillary meningioma, considered rare and seldom included as differential diagnosis in patients with neurological signs.

Computed tomographic, magnetic resonance imaging, and ultrasonographic characteristics of retrobulbar meningiomas in 15 dogs

“…[1][2][3] They have been described intracranially (82%), affecting the spinal cord (15%), and less commonly, within the retrobulbar space (2-3%). [2][3][4] Retrobulbar, orbital, or optic nerve sheath meningiomas arise from neoplastic transformation of the arachnoid cap cells within the optic nerve sheath or from extension of a primary intracranial tumor. 5,6 These masses are typically slow-growing, invading circumferentially into the surrounding connective tissues.…”

“…Meningiomas are the most common tumors of the central nervous system in dogs 1–3 . They have been described intracranially (82%), affecting the spinal cord (15%), and less commonly, within the retrobulbar space (2–3%) 2–4 . Retrobulbar, orbital, or optic nerve sheath meningiomas arise from neoplastic transformation of the arachnoid cap cells within the optic nerve sheath or from extension of a primary intracranial tumor 5,6 .…”