title: Presumed primary ocular lymphangiosarcoma with metastasis in a miniature horse.
abstract: A 7-year-old, 153.0-kg American Miniature mare presented for evaluation of keratoconjunctivitis of the right eye (OD). A superior palpebral conjunctival mass and stromal keratitis were diagnosed. The incisional biopsy diagnosis was a presumptive corneal hemangiosarcoma. Transpalpebral enucleation was performed, and histopathologic evaluation confirmed angiosarcoma of the conjunctiva, cornea, and extraocular muscles. The horse developed progressive epistaxis and orbital swelling following surgery. A systemic workup was performed 3 months after enucleation, revealing regrowth within the orbit and marked cranial cervical lymphomegaly, suggestive of metastasis. Humane euthanasia was performed, and necropsy confirmed a locally invasive periorbital tumor with metastasis to the submandibular tissue, submandibular lymph node, and thoracic inlet. Histopathologic evaluation of necropsy specimens revealed polygonal to spindle neoplastic cells lining neoplastic vascular channels lacking erythrocytes. Immunohistochemically, the neoplastic cells labeled strongly positive for PROX-1, vimentin, CD-31, VEGF, weakly positive for factor VIII-related antigen, and negative for collagen IV. Based on the clinical, histological, and immunohistochemical features of this tumor, a primary ocular lymphangiosarcoma with metastasis was diagnosed.
authors.affiliation: Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, 27606, USA.|North Carolina State University, Raleigh, NC, 27606, USA.
authors.forename: Joseph C
authors.initials: JC
authors.lastname: Gerding
authors.affiliation: Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, 27606, USA.|North Carolina State University, Raleigh, NC, 27606, USA.
authors.forename: Brian C
authors.initials: BC
authors.lastname: Gilger
authors.affiliation: Department of Pathology and Laboratory Medicine and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599-7525, USA.
authors.forename: Stephanie A
authors.initials: SA
authors.lastname: Montgomery
authors.affiliation: Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, 27606, USA.|North Carolina State University, Raleigh, NC, 27606, USA.|Port city Veterinary Referral Hospital, Portsmouth, NH, 03801, USA.
authors.forename: Alison B
authors.initials: AB
authors.lastname: Clode
mesh_terms: D000818:Animals; D003316:Corneal Diseases / Q000175:diagnosis / Q000473:pathology / Q000628:therapy / Q000662:veterinary*; D005134:Eye Neoplasms / Q000175:diagnosis / Q000473:pathology / Q000628:therapy / Q000662:veterinary*; D017809:Fatal Outcome; D005260:Female; D006734:Horse Diseases / Q000175:diagnosis* / Q000473:pathology; D006736:Horses; D008204:Lymphangiosarcoma / Q000175:diagnosis / Q000473:pathology / Q000628:therapy / Q000662:veterinary*
keywords: histopathology; horse; immunohistochemistry; lymphangiosarcoma; metastatic; ocular