Clinical and magnetic resonance imaging features of lymphoma involving the nervous system in cats

Abstract

Background Lymphoma is the most common spinal cord neoplasm and second most common intracranial tumor in cats, but description of specific magnetic resonance imaging (MRI) features is lacking. Objective Describe the clinical and MRI features of lymphoma affecting the central (CNS) or peripheral (PNS) nervous system or both in cats. Animals Thirty‐one cats with confirmed cytological or histopathological diagnosis or both of lymphoma involving the CNS or PNS or both, and MRI findings of the lesions. Methods Multicenter retrospective descriptive study. Signalment and medical information were recorded. Magnetic resonance imaging findings were reviewed by 3 observers following a list of predefined criteria and consensus was sought. Frequency distributions of the different categorical data were reported. Results Median duration of clinical signs at time of presentation was 14 days (range, 1‐90). Neurological examination was abnormal in 30/31 cats. On MRI, lesions affecting the CNS were diagnosed in 18/31 cats, lesions in both CNS and PNS in 12/31, and lesions in the PNS only in 1/31. Intracranial lesions were diagnosed in 22 cats (extra‐axial, 7/22; intra‐axial, 2/22; mixed, 13/22), and spinal lesions were diagnosed in 12 (6/12 involving the conus medullaris and lumbosacral plexuses). Infiltration of adjacent extra‐neural tissue was present in 11/31 cases. Contrast enhancement was seen in all lesions, being marked in 25/30. Meningeal enhancement was present in all but 2 cases. Several distinct MRI patterns were observed. Conclusions and Clinical Importance Nervous system lymphoma in cats has a wide range of MRI features, of which none is pathognomonic. However, together with clinical data and cerebrospinal fluid (CSF) analysis, MRI may provide a strong tentative antemortem diagnosis.

Clinical and magnetic resonance imaging features, and pathological findings of spinal lymphoma in 27 cats

“…Intradural-extramedullary lymphoma occurs as a nondelineated mass replacing the subdural and subarachnoid spaces, and commonly infiltrating the spinal cord parenchyma or nerve roots (1,20), but the pattern of intradural infiltration without an epidural mass was not found in our study. In a recent study (8) lesions frequently affected multiple spinal compartments similar to previous publications (1, 2) conversely, although intraduralextramedullary involvement with epidural lesions could be observed on MRI, both intra-and extramedullary involvement were present only in one lesion on this study. In humans, an epidural location for lymphoma is observed in 0.1-6.5% of all lymphomas (11).…”

“…Similarly, previous reports have described the MRI characteristics of spinal cord lymphoma in cats showing similar features to those seen in dogs (7) and to the intracranial counterpart (6), as lesions commonly indistinctively marginated from the surrounding tissue, mostly with a focal (80.6%) and extensive (64.5%) pattern (6,8). Others have also reported spinal lymphoma as focal, from 76% (21) to 95.6%, presented as a single lesion that may expand over more than one vertebral body, or multifocal, as two or more separate lesions (4).…”

“…On cytology, a diagnosis of lymphoma was considered if a population of lymphoid cells with atypical morphology was observed, which can include increased cell size (>2.5 times the upper limit of normal), irregular shape, and pointed borders of the cytoplasm, and nuclear atypia with any degree of sharp nuclear notches (13). When the diagnosis was based on cytology, only the samples with atypical large cells were considered in order to avoid possible diagnostic errors which could be induced by the morphological overlapping between small neoplastic lymphocytes and reactive lymphocytes (8,14).…”

“…Lymphoma is the most common spinal neoplasia in cats (1-3) and the second most common disease of the spinal cord (1, 2, 4, 5) but information about Magnetic Resonance Imaging (MRI) features is still scarce. To date, case series of feline spinal lymphoma have been limited to a few reports including limited cases (3,(6)(7)(8).…”

Case report: MRI findings with CNS blastomycosis in three domestic cats

“…CNS lymphoma has a variable imaging appearance in cats, with intra- and/or extra-axial masses of varying intensity and contrast enhancement patterns. While T2 hyperintensity is a more common feature and T2 hypointensity has not been reported, T2 isointensity is possible ( 28 ). Other substances and lesions that may appear hypointense on T2-weighted images are gadolinium-based contrast agents, mucous- or protein-containing lesions, highly cellular lesions, lesions containing mineral substances such as calcium, copper, or iron, turbulent and rapid blood (or CSF) flow, and air-containing spaces or lesions ( 29 ).…”