CASE REPORT Uveal schwannoma in a brown-eyed dog Todd L. Marlo,* Elizabeth A. Giuliano,* Cecil P. Moore,* Gillian C. Shaw† and Leandro B. C. Teixeira† *Department of Veterinary Medicine and Surgery, College of Veterinary Medicine, University of Missouri, Columbia, MO, USA; and †School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, USA Address communication to: E. A. Giuliano Tel.: 1-573-882-7821 Fax: 1-573-884-7563 e-mail: giulianoe@missouri.edu Abstract An eleven-year-old, female spayed Boxer dog was diagnosed with a uveal schwannoma (formerly known as the spindle cell tumor of the blue-eyed dog or SCTBED) despite having a uniformly brown iris. The patient presented to emergency for ocular discom- fort, and the right globe was subsequently enucleated due to glaucoma and submitted for histopathology. Upon histopathologic evaluation, a uveal schwannoma was diag- nosed and confirmed with immunohistochemical staining. Complete metastatic evalua- tion 1 and 6 months after initial presentation did not reveal evidence of metastasis, and the dog remains systemically healthy. This case represents a unique variant of uveal schwannoma and is relevant because although the vast majority of these tumors occur in blue-eyed dogs, clinicians should not completely rule out this tumor as a differential based on the iris color. Key Words: canine, intraocular, schwannoma, spindle cell tumor of blue-eyed dogs, tumor, uveal INTRODUCTION Peripheral nerve sheath tumors are most commonly found on the head and neck regions of both dogs and people. 1–3 While less common, schwannomas, a subset of peripheral nerve sheath tumors arising from Schwann cells, have been found in the iris, ciliary body, and choroid in people. 1 Zarfoss et al. 4 in 2007 first described a specific subset of intraocular uveal schwannomas in the canine population. Histologically, these tumors present as spindle-shaped mesenchymal cells in solid interwoven sheets with palisading nuclei. These tumors do not express melan-A or smooth muscle actin (SMA), but do express vimentin, S-100, and glial fibrillary acidic protein (GFAP) 4,5 as assessed by immunohistochemistry. To date, uveal schwannomas (formerly spindle cell tumor of blue-eyed dogs or SCTBED) have only been noted in dogs with blue or heterochromic irises with Siberian husky dogs being overrepresented. 4 Very little information is available on this tumor class as only three case reports confirming the diagnosis of uveal schwannomas (formerly SCTBED) are present in the literature 5–7 in addition to the Zarfoss et al. 4 report detailing 13 cases. In this report, we present a unique case of a Boxer dog with a completely brown iris developing a uveal schwannoma based on histopathologic and immuno- histochemical features. CASE PRESENTATION An eleven-year-old, spayed female, fawn-colored, Boxer dog was referred to the University of Missouri, Veterinary Health Center for glaucoma OD. Approximately 2 weeks prior to presentation, the owner noted ocular discomfort and redness OD (Fig. 1). Additionally, the owner reported approximately 1 year prior to presentation the iris of the dog’s right eye, which had been uniformly brown in color, underwent a grayish discoloration (Fig. 2). Prior to exami- nation, neomycin–polymyxin–dexamethasone ointment was dispensed by the primary care veterinarian and was applied OD twice daily for 7 days. Retroillumination revealed mydriasis OD. Complete neuro-ophthalmic examination indicated normal palpebral reflex, corneal sensitivity, and ocular motility OU. Menace response was absent OD and present OS. Dazzle reflex was absent OD and present OS. An absent direct pupillary light reflex was present OD; a consensual pupillary light reflex (left to right) was present OD. A direct pupillary light reflex was observed OS, but no consensual (right to left) pupillary light reflex was present OS. Schirmer I tear test (Merck © 2017 American College of Veterinary Ophthalmologists Veterinary Ophthalmology (2018) 21, 2, 205–209 DOI:10.1111/vop.12458