Paraganglioma of cauda equina: report of seven cases.

The authors report seven uncommon cases of paraganglioma of the cauda equina region with reference to their clinical, radiological, and pathological findings. The common presenting symptoms in all the patients were low backache with radiation to both thighs, sensory and motor deficits in four patients, and urinary retention in three patients. One patient presented with ataxia and superficial sidrosis of the brain. Magnetic resonance imaging (MRI) revealed well-circumscribed lesions that were isointense on T1- and T2-weighted images with flow voids. All the tumors were well circumscribed and could be excised completely; however, one recurred. Histological examination revealed a classic "zellballen" pattern in four tumors. Two mimicked ependymoma but were confirmed as paraganglioma by immunohistochemistry. MIB-1 LI was low in all the tumors. Thus, there were no identifying clinical or radiological features that helped in differentiating paraganglioma from other common tumors, such as ependymoma or neurinoma, in this region, and preoperative diagnosis was not possible in any of the cases. Morphologic features and immunohistochemical analysis proved to be the mainstay of arriving at a correct diagnosis. This report highlights the significance of important morphologic features and immunohistochemistry in the diagnosis of paraganglioma at this unusual site.