title: Equine histoplasmosis presenting as a tumor in the abdominal cavity.
abstract: A 3.5-year-old Thoroughbred mare presented at necropsy with a large mass at the root of the mesentery and multiple smaller mesenteric masses. The mucosa of the small intestine contained numerous raised nodules. Histologic examination revealed severe granulomatous mesenteric lymphadenitis and enteritis. Epithelioid macrophages and multinucleated giant cells frequently contained numerous intracytoplasmic yeast organisms, which were strongly positive on immunohistochemical staining when using a polyclonal antibody against Histoplasma spp. A diagnosis of abdominal histoplasmosis was made based on the gross, microscopic, and immunohistochemical findings.
authors.affiliation: Department of Veterinary Pathobiology, College of Veterinary Medicine, Texas A&M University, College Station, TX 77843-4467, USA.
authors.forename: Jairo
authors.initials: J
authors.lastname: Nunes
authors.forename: John T
authors.initials: JT
authors.lastname: Mackie
authors.forename: Matti
authors.initials: M
authors.lastname: Kiupel
mesh_terms: D000818:Animals; D003937:Diagnosis, Differential; D017809:Fatal Outcome; D005260:Female; D006651:Histocytochemistry / Q000662:veterinary; D006658:Histoplasma / Q000254:growth & development*; D006660:Histoplasmosis / Q000175:diagnosis / Q000382:microbiology / Q000473:pathology / Q000662:veterinary*; D006734:Horse Diseases / Q000175:diagnosis / Q000382:microbiology* / Q000473:pathology; D006736:Horses; D007078:Ileal Neoplasms / Q000175:diagnosis / Q000473:pathology / Q000662:veterinary*