Two cases of normal pressure hydrocephalus caused by ependymoma of the cauda equina

INTRODUCTION

Normal pressure hydrocephalus (NPH) associated with tumors of the cauda equina is rare.[1,5] Here, we treated two patients with NPH and ependymoma of the cauda equina successfully treated with surgery: in the first case, the patient underwent lumbar decompressive L2-L3 surgery for tumor excision, followed by ventriculoperitoneal (VP) shunt placement for NPH, while in the second case, VP shunt placement for NPH was succeeded by T12-L2 laminectomy for tumor removal.

CASE DESCRIPTION

Case 1

A 63-year-old male developed right lower extremity weakness over a 6-month period associated with gait disturbance, dementia, and urinary incontinence. The lumbar MR demonstrated an intradural tumor at the L2-L3 level involving the cauda equina: the lesion was hypointense on T1 and hyperintense on T2-weighted images, but due to renal failure, no contrast was administered [Figure 1a-c]. A head CT showed hydrocephalus/diagnosed as NPH [Figure 1d]. Gross total removal of the intradural reddish tumor that originated from a nerve root was accomplished [Figure 2a and b]. Pathologically, the lesion was a myxopapillary ependymoma [Figure 3]. Postoperatively, when the patient continued to demonstrate gait disturbance, a head CT showed hydrocephalus/diagnosed as NPH and required VP shunt placement [Table 1].

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Figure 1:: Radiographic findings of case 1. (a) T2 sagittal image showing an intradural extramedullary mass at the level of L2-L3. (b) T1 sagittal image. (c) T2 axial image. (d) Head computed tomography demonstrating enlargement of the ventricles.

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Figure 2:: Intraoperative microscopic view. (a) A deep red-colored tumor can be seen. (b) The tumor originates from a cauda equina nerve (yellow arrow).

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Figure 3:: Hematoxylin and eosin stain high-power view (×20). Perivascular pseudorosettes were found from tumor cells tapering radial to blood vessels. Myxoid material is present within pseudorosettes.

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Table 1:: Clinical data on two patients with NPH and thoraco/lumbar ependymomas.

Case 2

A 65-year-old female also presented with gait disturbance, dementia, and urinary retention; her neurological examination only revealed an ataxic gait. The brain CT demonstrated ventricular dilation consistent with NPH and a VP shunt was placed [Figure 4a and Table 1]. However, as the urinary retention/sphincter dysfunction persisted, a lumbar MRI was obtained; it shows an intradural T12-L2 tumor that was hypointense on T1 and hyperintense on T2-weighted images, and markedly enhanced with gadolinium [Figure 4b-e]. At surgery, although some cauda equina nerves were attached to the tumor, internal decompression was accomplished utilizing an ultrasonic aspirator and facilitated gross total tumor excision. Pathologically, the lesion was an ependymoma. Postoperatively, the patient’s deficit remained unchanged, and she continues to self-urinary catheterize 10 years later.

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Figure 4:: Radiographic findings of case 2. (a) Head computed tomography image demonstrating enlargement of the ventricles. (b) T2 axial image showing an intradural extramedullary mass at the L1. (c) T2 sagittal image. (d) T1 sagittal image. (e) T1 contrast-enhanced sagittal image.

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DISCUSSION

NPH associated with tumors of the cauda equina is rare.[1,5] While neurinomas frequently produce gradually progressive hydrocephalus, ependymomas, including myxopapillary thoraco/lumbar ependymomas, can also contribute to hydrocephalus/intracranial hypertension (ICH).[3,4] Treatment of ICH may warrant ventriculoperitoneal shunting and tumor excision in varying sequences.[2,5] Here, in case 1, NPH did not improve after L2-L3 ependymoma tumor was removed, and warranted secondary, VP shunt placement. Alternatively, in case 2, initial VP shunt placement did not resolve the patient’s complaints, and secondary T12-L2 laminectomy for excision of the cauda equina ependymoma was necessary.

CONCLUSION

Here, we presented two cases of cauda equina ependymomas that contributed to increased intracranial pressure (e.g., consistent with NPH). The first patient required primary thoracolumbar/lumbar L2-L3 ependymoma tumor excision followed by secondary VP shunting, while in the second case, initial VP shunting was succeeded by T12-L2 laminectomy for tumor removal.