title: Thymic cystic degeneration, pseudoepitheliomatous hyperplasia, and hemorrhage in a dog with brodifacoum toxicosis.
abstract: Thymic cysts with pseudoepitheliomatous hyperplasia are described in a 7-month-old female American Eskimo Dog that died of complications from brodifacoum poisoning. Grossly, there was hemothorax with marked cranial mediastinal hemorrhage. Histologically, thymic lobules were expanded and distorted by irregular cysts, lined by single to multiple layers of plump to slightly attenuated polygonal squamous epithelial cells supported by a basement membrane (pseudoepitheliomatous hyperplasia). The thymus had a paucity of lymphocytes and lacked corticomedullary differentiation. Extensive hemorrhage within the cysts and thymic parenchyma extended into the adjacent adipose tissue. To the authors' knowledge, this is the first report of cystic thymic degeneration with pseudoepitheliomatous hyperplasia in a nonhuman species.
authors.affiliation: San Diego County Animal Disease Diagnostic Laboratory, Department of Agriculture, Weights, and Measures, 5555 Overland Avenue, Building 4, San Diego, CA 92123, USA. barry.rickman@sdcounty.ca.gov
authors.forename: B H
authors.initials: BH
authors.lastname: Rickman
authors.forename: N
authors.initials: N
authors.lastname: Gurfield
mesh_terms: D015110:4-Hydroxycoumarins / Q000506:poisoning*; D000818:Animals; D004283:Dog Diseases / Q000139:chemically induced* / Q000473:pathology; D004285:Dogs; D004848:Epithelium / Q000473:pathology; D005260:Female; D006965:Hyperplasia / Q000473:pathology / Q000662:veterinary*; D012378:Rodenticides / Q000506:poisoning*; D013950:Thymus Gland / Q000187:drug effects / Q000473:pathology*
chemical_list: D015110:4-Hydroxycoumarins; D012378:Rodenticides; C013418:bromfenacoum