title: Hemangiosarcoma and squamous cell carcinoma in the third eyelid of a horse.
abstract: A 12-year-old Belgian draft horse presented for a right eye third eyelid mass and red-tinged ocular discharge of 3 months' duration. The third eyelid was excised and submitted for histopathology. On histopathologic examination, the mass was composed of both hemangiosarcoma and squamous cell carcinoma. The horse developed thickened eyelids and hemorrhagic ocular discharge from the right eye approximately 16 months following surgery, and was euthanized. Necropsy and histopathology confirmed local recurrence and regional metastasis of the hemangiosarcoma. This was an unusual case because there were two distinct neoplastic processes composing the same mass that could not be differentiated grossly.
authors.affiliation: Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, D-208 Veterinary Medical Center, East Lansing, MI 48824-1314, USA. gearhart@cvm.msu.edu
authors.forename: Patricia M
authors.initials: PM
authors.lastname: Gearhart
authors.forename: Barbara A
authors.initials: BA
authors.lastname: Steficek
authors.forename: Simon M
authors.initials: SM
authors.lastname: Peteresen-Jones
mesh_terms: D000818:Animals; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis / Q000662:veterinary*; D003937:Diagnosis, Differential; D005142:Eyelid Neoplasms / Q000175:diagnosis / Q000662:veterinary*; D006394:Hemangiosarcoma / Q000175:diagnosis / Q000662:veterinary*; D006734:Horse Diseases / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery; D006736:Horses; D008297:Male; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis / Q000662:veterinary*; D009378:Neoplasms, Multiple Primary / Q000175:diagnosis / Q000662:veterinary*; D009541:Nictitating Membrane; D013508:Ophthalmologic Surgical Procedures / Q000662:veterinary