Paraganglioma of the cauda equina

Abstract

● Received: January 25, 2015 ● Revised: February 10, 2015 ● Accepted: February 11, 2015 Corresponding Author: Miguel Gelabert-Gonzalez, MD University of Santiago de Compostela (Spain), San Francisco 1, Santiago de Compostela, Spain Tel: +34981950331, Fax: +34981950404 E-mail: miguel.gelabert@usc.es ◯∝This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/ licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. We would like to make the following observations, on the basis of our personal experience, in relation to the recent article by San OH Spinal paraganglioma adherent to the cauda equina. Firstly, we do not share the assertion of authors: “Locations in the cauda equina are exceptional”; in our review published in 2005 about previously 174 reported cases of lumbar paragangliomas, 57 patients (33.9%) had their tumor adhered to the cauda equina. Secondly, the authors indicate that ependymomas are classified as WHO grade II-III, however, more than 90% of ependymomas located in the cauda equina-filum terminale are mixopapyllary (WHO grade I). Thirdly, we agree with the authors that the differential diagnosis must be made with ependymomas of the filum terminal, but also with other tumors in the same location as schwannomas and meningiomas. Paragangliomas are usually hypoor isointense to the conus medullaris on T1-weighted sequences, whereas it is hyperintense on T2-weighted sequences, sometimes inhomogeneous, and in some cases cystic areas have been reported. After Gd injection, there was marked enhancement; in other cases a serpiginous area of flow voids was observed, which suggested vessels capping the tumor. Araki, et al., suggested that this sign is a major clue to the diagnosis of a highly vascular lesion. Hypointense tumor margins on T2-weighted MR and proton-density imaging may indicate hemosiderin or ferritin from previous hemorrhages. It is dificult to distinguish paragangliomas from meningiomas and schwannomas because the latter are all hypoor isointense with respect to the spinal cord on T1-weighted and isoor hyperintense on T2-weighted images. Postcontrast enhancement, however, is homogeneous in schwannoma and meningioma, and no report of a lowintensity band or hemosiderin rim has been documented by MR imaging in cases of these tumors. Moreover, preoperatively paragangliomas can be differentiated from these tumors based on the presence of hemorrhage and cyst formation in schwannoma and calcification in meningioma.