Allett B, Hecht S.
Introduction/Purpose: Lymphoma is one of the most common neoplasms in the dog, and the multicentric form accounts for approximately 80% of cases. Lesions can involve any tissues outside of the lymphatic system including the central nervous system (CNS). Despite the prevalence of lymphoma and the increasing use of magnetic resonance (MR) imaging, reports of lymphoma affecting the spine have been limited to case reports. The purpose of this study was to describe the MR imaging findings in dogs with lymphoma affecting the spine and/or paraspinal soft tissues.
Methods: Medical records at our institution were searched for patients that had MR imaging of the spine and had a diagnosis of lymphoma of the spine or paraspinal tissues during the period of 2009 – 2013. The MRI studies were evaluated for the presence of focal or multifocal disease, identification of the structures involved including the spinal cord , meninges , spinal canal , vertebrae , and paraspinal soft tissues , and the signal characteristics on T2-W , T1-W , STIR, HASTE and T1-W sequences prior to and following intravenous contrast medium administration.
Results: Six dogs with a median age of 7 years (range of 1 – 10 years) met the inclusion criteria. Common MRI findings included multifocal disease (5/6), involvement of one (2/6) or multiple (3/6) vertebrae, a variable degree of spinal cord compression (4/6) and involvement of the paraspinal soft tissues (5/6). Vertebral changes were confined to the medullary cavity without evidence of osteolysis and were best seen on STIR and post contrast images. There was questionable involvement of the spinal cord in only one case. All spinal and paraspinal lesions identified were hyperintense on T2-W and STIR sequences and showed variable contrast enhancement.
Discussion/Conclusion: Imaging findings of lymphoma affecting the spine and paraspinal soft tissues typically were multifocal and involved a combination of vertebrae , spinal canal and paraspinal soft tissues. Lesions were commonly T2-W and STIR hyperintense and displayed contrast enhancement. The STIR and T1-W post-contrast sequences were subjectively the most useful in identification of the lesions.