Myocardial plasma cell tumor with intratumoral amyloidosis in a dog.

A 12-year-old mixed breed dog was evaluated for marked hypercalcemia that was identified during assessment for acute polydipsia and polyuria. Physical examination identified a new grade II/VI left apical systolic murmur. A mass involving the left ventricular posterior wall and left atrium was identified by echocardiography, suggesting neoplastic invasion into the myocardium. The patient was euthanized, and post-mortem cardiac evaluation identified an intramyocardial amyloid-producing plasma cell tumor. Multiple myeloma was suspected but could not be confirmed due to the limited post-mortem evaluation. This case is the first report of myocardial amyloidosis in a dog with a myeloma-related disorder (MRD). Dogs with MRD and myocardial involvement may not exhibit clinical signs that localize to the cardiovascular system; therefore, echocardiography should be considered during the staging process.

Paraparesis in a Golden Retriever.

A 7-year-old female spayed Golden Retriever dog presented with fever and a 10-day history of neurological signs, including ambulatory paraparesis and pelvic limb ataxia. Neurological examination initially revealed a T3-L3 myelopathy. Thoracic radiographs revealed a diffuse miliary pulmonary pattern. Endotracheal washes and fine-needle aspirates from several organs aimed at identifying a potential infectious agent or neoplastic process were all unsuccessful. Due to worsening of the clinical signs, euthanasia was elected. Necropsy findings included multifocal, pale to dark red, firm nodules infiltrating the lungs, heart, mesentery, pancreas, small intestine, brain, and spinal cord. Cytological examination of impression smears obtained from the pulmonary nodules during necropsy revealed clusters of epithelioid cells admixed with fewer spindle cells, erythrocytes, and scattered leukocytes. Clinical signs and cytological findings initially suggested the possibility of a widespread granulomatous disease or a metastatic epithelial neoplasm as possible clinical differentials in this case. The final diagnosis was based on the gross and histological findings, with confirmation following histochemistry and immunohistochemistry.

Mannheimia haemolytica A1-induced fibrinosuppurative meningoencephalitis in a naturally-infected Holstein-Friesian calf.

Mannheimia haemolytica is an opportunistic bacterium that is widely recognized among the bovine respiratory disease complex as the predominant pathogen causing broncho- and pleuropneumonia in cattle. Among the characterized M. haemolytica serotypes, A1 is the major cause of severe pulmonary lesions in cattle. This report describes post-mortem findings in a Holstein-Friesian calf with fibrinosuppurative meningoencephalitis and fibrinonecrotizing, haemorrhagic broncho- and pleuropneumonia, from which M. haemolytica and bovine viral diarrhoea virus (BVDV) were isolated. Microscopical evaluation showed expansion of the brainstem and cerebellar leptomeninges by neutrophils and fibrin, associated with gram-negative coccobacilli. Occasional blood vessels within the midbrain and cerebellum contained fibrin thrombi. Bacterial culture of cerebellum and lung yielded M. haemolytica with unusually high haemolytic activity. The isolates were confirmed as serotype A1 by rapid plate agglutination. Lung tissue was positive for BVDV by polymerase chain reaction. The broncho- and pleuropneumonia in this calf were consistent with typical mannheimiosis due to serotype A1; however, extrapulmonary infections due to M. haemolytica, as seen in this case, are rarely reported. To our knowledge, this is the first documentation of a natural BVDV and M. haemolytica co-infection associated with fibrinosuppurative meningoencephalitis in a calf.