A Grade IV Glioblastoma with an Oligodendroglial Component (GBM-O) in a Horse
The William R. Pritchard Veterinary Medical Teaching Hospital, University of California, Davis, USA. Journal of comparative pathology
(Impact Factor: 1.14).
11/2009; 142(4):332-5. DOI: 10.1016/j.jcpa.2009.09.007
A 4-year-old Dutch warmblood mare was presented with a 10-month history of ataxia and proprioceptive deficits. Computed tomography defined a large, non-contrast enhancing mass in the left cerebral hemisphere. Necropsy examination revealed a tumour that effaced much of the piriform and temporal lobes. Microscopically the lesion was classified as a grade IV glioblastoma with an oligodendroglial component (GBM-O). The tumour was composed of highly pleomorphic cells organized in different patterns within a fibrillary stroma. There were multiple foci of necrosis. At the periphery of the tumour neoplastic oligodendroglioma-like cells were embedded in an extracellular mucinous matrix. Most neoplastic cells were strongly immunoreactive for glial fibrillary acidic protein; however, the oligodendroglioma cells did not express this marker. Cells forming microvascular proliferations were positively labelled for expression of factor VIII and smooth muscle actin. All neoplastic cells were negative for Neu-N and synaptophysin. The proliferation index was up to 5%. All neoplastic cells and normal brain tissue from the horse were uniformly negative for expression of epidermal growth factor receptor (EGFR), EGFR vIII mutant and the phosphatase and tensin homologue (PTEN) compared with positive control human GBM tissue. To our knowledge this is the first report of a GBM-O in the horse.
Available from: Nicole Gottdenker
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ABSTRACT: Central nervous system tumors are rarely reported in cervids. The current report describes gross and histopathologic oligodendrogliomas in 3 white-tailed deer (Odocoileus virginianus), and selected immunohistochemical properties of 2 deer. All deer were euthanized due to central nervous system signs. Grossly, masses were variably circumscribed, locally invasive in the brain, light grey, and soft, and ranged from 2 to 5 cm in diameter. Histologically, tumors were characteristic for oligodendroglioma. The tumors were composed primarily of oval to round cells with round normochromatic to hyperchromatic nuclei, a pale granular cytoplasm, and well-delineated cytoplasmic membrane, and variable amounts of mucinous material, hemorrhage, and dystrophic mineralization. Immunohistochemistry, performed on masses from 2 deer, had positive cytoplasmic staining for S100 and variable staining on glial fibrillary acidic protein (1 deer negative and the other with rare positivity in astrocytes within the mass). This manuscript includes a discussion on the significance of these findings relative to central nervous system tumors of cervids and oligodendrogliomas from other species.
Available from: Rick Gerhold
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ABSTRACT: Background: Brainstem auditory evoked response has been an underused diagnostic modality in horses as evidenced by few reports on the subject. Hypothesis/Objectives: To describe BAER findings, common clinical signs, and causes of hearing loss in adult horses. Animals: Study group, 76 horses; control group, 8 horses. Methods: Retrospective. BAER records from the Clinical Neurophysiology Laboratory were reviewed from the years of 1982 to 2013. Peak latencies, amplitudes, and interpeak intervals were measured when visible. Horses were grouped under disease categories. Descriptive statistics and a posthoc Bonferroni test were performed. Results: Fifty-seven of 76 horses had BAER deficits. There was no breed or sex predisposition, with the exception of American Paint horses diagnosed with congenital sensorineural deafness. Eighty-six percent (n = 49/57) of the horses were younger than 16 years of age. The most common causes of BAER abnormalities were temporohyoid osteoarthropathy (THO, n = 20/20; abnormalities/total), congenital sensorineural deafness in Paint horses (17/17), multifocal brain disease (13/16), and otitis media/interna (4/4). Auditory loss was bilateral and unilateral in 74% (n = 42/57) and 26% (n = 15/57) of the horses, respectively. The most common causes of bilateral auditory loss were sensorineural deafness, THO, and multifocal brain disease whereas THO and otitis were the most common causes of unilateral deficits. Conclusions and Clinical Importance: Auditory deficits should be investigated in horses with altered behavior, THO, multifocal brain disease, otitis, and in horses with certain coat and eye color patterns. BAER testing is an objective and noninvasive diagnostic modality to assess auditory function in horses. © 2014 by the American College of Veterinary Internal Medicine.
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