Thoracic and abdominal blastomycosis in a horse

A 5-year-old Quarter Horse mare was examined because of lethargy, fever, and weight loss of 1 month's duration. Thoracic auscultation revealed decreased lung sounds cranioventrally. Thoracic ultrasonography revealed bilateral anechoic areas with hyperechoic strands, consistent with pleural effusion and fibrin tags. A large amount of free fluid was evident during abdominal ultrasonography. Abnormalities included anemia, hyperproteinemia, hyperglobulinemia, hyperfibrinogenemia, and hypoalbuminemia. Thoracic radiography revealed alveolar infiltrates in the cranial and caudoventral lung fields. A cavitary mass, consistent with an abscess, could be seen caudodorsal to the crura of the diaphragm. Ultrasonographic evaluation of this area revealed a hypoechoic mass with septations. Bilateral thoracocentesis was performed. Bacterial culture of the pleural fluid did not yield growth, but Blastomyces dermatitidis was isolated from pleural fluid, abdominal fluid, and an aspirate of the abscess. The mare was euthanatized, and a diagnosis of thoracic and abdominal blastomycosis was confirmed at necropsy.