title: Bacterial pleuritis with thickened mesothelial hyperplasia in a young beagle dog.
abstract: A five-month-old male beagle dog suddenly became moribund. Bloody fluid accumulated in the thoracic and abdominal cavities, and soft yellow flecks were floating in the thoracic fluid. The mediastinum and pericardium became dark reddish with villous thickening. Other parietal and pulmonary pleurae were rough, and the organs adhered to each other. Histologically, most mediastinal pleura formed papillary projections covered by a single layer of mesothelial cells. Many macrophages and neutrophils infiltrated the submesothelial connective tissue. At the mediastinum adjacent to the pericardium, cuboidal mesothelial cells proliferated solidly and formed a thick surface stratum. The flecks consisted of gram-negative filamentous or small bacillary (coccoid) bacteria. In the right posterior lobe of the lung, neutrophilic infiltration and a large encapsulated abscess including a bacterial colony were present. We diagnosed this case as "bacterial pleuritis with thickened mesothelial hyperplasia". The cause of the pleuritis might be a chronic pleural infection spread via the lung abscess.
authors.affiliation: Pathology Department, Kashima Laboratory, Nonclinical Research Center, Mitsubishi Chemical Medience Corporation, 14-1 Sunayama, Kamisu, Ibaraki 314-0255, Japan.
authors.forename: Naoaki
authors.initials: N
authors.lastname: Yamada
authors.forename: Satomi
authors.initials: S
authors.lastname: Hashimoto
authors.forename: Yuki
authors.initials: Y
authors.lastname: Tomonari
authors.forename: Hiroko
authors.initials: H
authors.lastname: Kokoshima
authors.forename: Takuya
authors.initials: T
authors.lastname: Doi
authors.forename: Junko
authors.initials: J
authors.lastname: Sato
authors.forename: Yumi
authors.initials: Y
authors.lastname: Wako
authors.forename: Minoru
authors.initials: M
authors.lastname: Tsuchitani
keywords: Acinetobacter lwoffii; Escherichia coli; Serratia odorifera; bacterial pleuritis; beagle dog; mesothelial hyperplasia