MRI FEATURES OF CNS LYMPHOMA IN DOGS AND CATS

Abstract

The magnetic resonance (MR) imaging features of central nervous system lymphoma in eight dogs and four cats are described. Intracranial lesions affected the rostrotentorial structures in six dogs and caudotentorial structures in two cats. Lesions affected the spinal cord in two dogs and in two cats. One dog and one cat with intracranial lymphoma had signs of local extracranial extension and lymphadenopathy. Lesions were considered extraparenchymal in four dogs and three cats, intraparenchymal in two dogs and one cat, and appeared to have both intra- and extraparenchymal components in two dogs. All lesions were hyperintense in T2-weighted images when compared to white matter, most were hypointense in T1-weighted images (7/12), and most were hyperintense in fluid-attenuated inversion recovery (FLAIR) images (5/9). When compared to grey matter, these lesions appear either isointense (5/12) or hyperintense (7/12) on T2-weighted images, half of them were hypointense in T1-weighted images (6/12), and most were isointense in FLAIR images (7/9). Lesion margins were usually indistinct in T2-weighted images (10/12) and had perilesional hyperintensity in FLAIR images (7/9). The majority of lesions (10/12) had abnormal meninges around the lesion and half (6/12) had generalized contrast enhancement. Mass effect was evident in all lesions. Although not specific, when combined with the history and neurologic signs, MR features aid presumptive diagnosis that should be confirmed by cytology or histopathology.

Imaging Diagnosis—magnetic Resonance Imaging Features of a Cerebral Hemangioblastoma in a Dog

“…However, the MRI characteristics are nonspecific and similar findings can readily occur with other extraparenchymal neoplasms, notably histiocytic sarcoma 11,12 and lymphoma. 12,13 While MRI is the imaging modality of choice for brain neoplasms, misclassification of lesions in regards of their location relative to the meninges or to their histopathological nature is not uncommon. 14, 15 A recent study reported that about 30% of intracranial neoplasms can be misclassified based on imaging description.…”

Histiocytic Sarcoma with Central Nervous System Involvement in Dogs: 19 Cases (2006–2012)

“…This, together with the observation in other reports of neoplastic cells on CSF evaluation, suggests that dissemination of HS through the subarachnoid space occurs more commonly than with most other neoplasms, similar to CNS lymphoma. Another similarity between these tumor types is the diversity of potential CNS manifestations, as both HS and lymphoma can be found in extraaxial or intra‐axial/intramedullary locations, with a multifocal distribution or as a diffuse meningeal lesion 23, 24. The combination of mass lesions in conjunction with diffuse or remote meningeal enhancement, pleocytosis and potentially brain herniation is quite characteristic, and should prompt clinicians to consider HS as a potential diagnosis.…”

Inflammatory pseudotumour arising in the epidural space of a dog

“…The differential diagnosis considered in extradural mass without bone destruction includes lymphoma, myelolipoma, steatitis and empyema (Lavely and others 2006, Ueno and others 2007, Aikawa and others 2008, De Stefani and others 2008, Murata and others 2012, Nishida and others 2012, Palus and others 2012, Cornelis and others 2013, Hoffmann and others 2013). …”

“…Typical MR findings of these lesions are hyperintensity on T2W images (Ueno and others 2007, Murata and others 2012, Palus and others 2012, Cornelis and others 2013, Hoffmann and others 2013). In contrast, IPTs show hypointensity on T2W images (Han and others 1996, Aizawa and others 2002, Despeyroux-Ewers and others 2003, Loderstedt and others 2010), which differ from the signal intensity in our case.…”