title: A canine case of primary intra-right atrial paraganglioma.
abstract: An 11-year-old mixed breed dog was presented with signs of anorexia. Radiographic and ultrasound examinations revealed a large mass in the heart, between the right atrium and the right ventricle. Upon gross inspection, a multilobulated tumor arising from the right atrial wall and occupying the right atrium was identified. Microscopical analysis demonstrated that this tumor consisted of neoplastic cells with granular cytoplasm, which were separated into nests by fine fibrovascular stroma and were negative for Grimelius's method. Immunohistochemical examinations revealed that the neoplastic cells expressed chromogranin A, synaptophysin and neuron specific enolase. Electron microscopy revealed that the cytoplasm of the neoplastic cells held secretory granules. Based on these pathological findings, the tumor was diagnosed as a paraganglioma. This report is a rare case of primary paraganglioma deriving from the right atrium and provides a detailed characterization of its morphological features.
authors.affiliation: Laboratory of Veterinary Pathology, School of Veterinary Medicine, Kitasato University, Towada, Aomori, Japan.
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Yanagawa
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Hatai
authors.forename: Takahiro
authors.initials: T
authors.lastname: Taoda
authors.forename: Hassadin
authors.initials: H
authors.lastname: Boonsriroj
authors.forename: Kazunori
authors.initials: K
authors.lastname: Kimitsuki
authors.forename: Chun-Ho
authors.initials: CH
authors.lastname: Park
authors.forename: Toshifumi
authors.initials: T
authors.lastname: Oyamada
mesh_terms: D000818:Animals; D004283:Dog Diseases / Q000473:pathology*; D004285:Dogs; D005260:Female; D006338:Heart Neoplasms / Q000473:pathology / Q000662:veterinary*; D010235:Paraganglioma / Q000473:pathology / Q000662:veterinary*