Original Research ARTICLE
Glioma Mimics: Magnetic Resonance Imaging Characteristics of Granulomas in Dogs
- 1Department of Veterinary Clinical Sciences, Purdue University, United States
- 2Department of Neurological Surgery, Indiana University, United States
- 3Department of Comparative Pathobiology, Purdue University, United States
- 4Department of Veterinary Clinical Medicine, University of Illinois at Urbana-Champaign, United States
- 5Department of Small Animal Clinical Sciences, Virginia Tech, United States
Granulomas can “mimic” gliomas on magnetic resonance imaging (MRI) in human patients. The goal of this retrospective study was to report canine brain granulomas that were consistent with glioma based upon MRI, report their histologic diagnosis, and identify MRI criteria that might be useful to distinguish granuloma from glioma. Ten granulomas, initially suspected to be glioma based on MRI, were ultimately diagnosed as granulomatous meningoencephalomyelitis (n = 5), infectious granulomas (n = 3) or other meningoencephalitis (n = 2). Age was 1.6 to 15.0 years and two dogs were brachycephalic breeds. MRI characteristics overlapping with glioma included intra-axial, heterogeneous, T2-weighted hyperintense, T1-weighted hypointense to isointense mass lesions with contrast-enhancement. Signals on fluid attenuation inversion recovery, gradient echo and diffusion weighted imaging also matched glioma. Peri-lesional edema and mass effect were towards the high end of findings reported for glioma. MRI characteristics that would be considered unusual for glioma included dural contact (n = 4), T2-hypointensity (n = 2), concomitant meningeal-enhancement (n = 9) and minor changes in the contralateral brain (n = 2). Cerebrospinal fluid analysis revealed albuminocytological dissociation or mild pleocytosis. These cases show that granulomas can “mimic” glioma on canine brain MRI. In individual cases, certain MRI findings may help increase the index of suspicion for granuloma. Lack of pronounced cerebrospinal fluid pleocytosis does not exclude granuloma. Signalment is very useful in the suspicion of glioma, and many of these dogs with granuloma were of ages and breeds in which glioma is less commonly seen.
Keywords: Brain, canine, Fungal, Granulomatous meningoencephalomyelitis, Pseudotumor
Received: 12 Apr 2019;
Accepted: 13 Aug 2019.
Copyright: © 2019 Diangelo, Cohen-Gadol, Heng, Miller, Hague, Rossmeisl and Bentley. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Mx. R. Timothy Bentley, Purdue University, Department of Veterinary Clinical Sciences, West Lafayette, 47907, Indiana, United States, email@example.com