Recurrent craniospinal epidermoid: A case report.

We present a rare case of a fourth ventricular epidermoid cyst, which recurred 15 years after the initial radical tumor resection surgery. The recurrence of the tumor extended into the cervical spine. The patient was reoperated and a near-total excision of both the cranial and spinal components of the epidermoid was performed. Our literature search did not reveal any case where there was a simultaneous presence of both the cranial and spinal epidermoid tumors. The possible cause of extension of the cranial epidermoid into the spinal compartment is analyzed.

INTRODUCTION

Epidermoid tumors are rare tumors that grow in discreet silence over years.[1] These tumors are believed to arise from strayed ectodermal cells during neural tube closure. The tumors then grow by accrual of desquamated epithelial cell debris leisurely over time. They insinuate themselves into cisterns and subarachnoid spaces but maintain “symbiosis” with the brain, which distorts itself, allowing these tumors to attain large sizes before being detected.[1] Intracranial epidermoid tumors are more frequently encountered than intraspinal epidermoid tumors. We present a rare case of craniospinal recurrence of a fourth ventricular epidermoid tumor and discuss the relevant pathophysiology.

CASE REPORT

A 50-year-old male patient was operated for a fourth ventricular epidermoid in 1998 at our institute. He had promptly improved in his preoperative symptoms of headache, visual blurring, and gait ataxia after the first surgery. His postoperative course was uneventful except for cerebrospinal fluid leakage from the wound site. This was managed conservatively with lumbar drainage of cerebrospinal fluid multiple times. He was asymptomatic for the next 15 years. He again presented to us with recent-onset headache, giddiness, and weakness in all four limbs for the last 3 months. Neurological examination revealed spastic quadriparesis of grade 3/5. Magnetic resonance imaging (MRI) of the brain with the spine showed a recurrent fourth ventricular epidermoid. The lesion was hypointense on T1W images, hyperintense on T2W images, and did not show any enhancement on gadolinium injection. Diffusion-weighted images showed a restricted diffusion [Figures 1–3]. MRI of the cervical spine showed a lesion with similar intensity in the cervical spinal intradural space extending from C1 to C2. There was a distinct region without any tumor between the fourth ventricular and the spinal components [Figure 2]. The patient was reoperated. The previous midline suboccipital craniotomy was reexplored. The exposure was extended down with C1-C2 laminectomy to facilitate removal of the spinal component. On opening the dura, pearly white flakes with a thin surrounding capsule consistent with an epidermoid tumor was identified in the fourth ventricle and in the cervical spinal subdural space [Figure 4]. Both the tumors were separate from each other. A radical removal of the craniospinal epidermoid was achieved, leaving behind only tiny fragments of capsule densely adherent to the floor of the fourth ventricle and brainstem. The patient improved in his symptoms of weakness in the limbs and giddiness. Postoperative magnetic MRI showed a gross total excision of the craniospinal epidermoid [Figure 5]. At a follow-up of 2 years, the patient was fine and had no neurological deficit.

Figure 1

Axial T2-weighted image showing a hyperintense lesion in the fourth ventricle, suggestive of a fourth ventricular epidermoid cyst

Figure 3

Diffusion-weighted image showing the restricted diffusion typical of an epidermoid cyst

Figure 2

Sagittal T1-weighted image of the posterior fossa and upper cervical spine showing the hypointense lesion in the fourth ventricle and another lesion in the upper cervical spine. The two lesions are separate from each other

Figure 4

Intraoperative image showing the fourth ventricular epidermoid and another epidermoid cyst in the region of the upper cervical spine, distinct from each other

Figure 5

Postoperative diffusion-weighted image showing near-total excision of the tumor

DISCUSSION

Epidermoid tumors account for approximately 0.2-1.8% of all intracranial tumors and less than 1% of spinal tumors.[23] The fourth ventricle is a rare location for the occurrence of these tumors.[456] Although these lesions are mainly congenital, patients are usually symptomatic in their third decade to fifth decade. Iatrogenic cases of intraspinal epidermoids have been reported following lumbar puncture. These occur due to implantation of epidermal cells from the skin into the subarachnoid space following the puncture. Defect in the cleavage of neural tissue from the cutaneous ectoderm, embryonic inclusions, trauma, differentiation from multipotential cell rests and epithelial remnants are the various other mechanisms implicated in the origin of epidermoid tumor.

Surgery remains the mainstay for these tumors. Since the capsule of the cyst is the only living or growing part of the tumor, many authors advocate a total removal of the cyst wall. However, this task can be daunting and potentially dangerous due to adherence and intimate relationship of the capsule to the brainstem, cranial nerves, and perforators. We have previously advocated a safe radical excision of the cyst wall and its contents and excision of as much of capsule as was safely possible without aiming at complete resection with good results and low recurrence rates.[23]

Considering the benign nature and slow growth rate, the recurrence rate of the tumors is low.[23] The most common identified cause of recurrence is incomplete excision of the tumor and its capsule. Rupture of the epidermoid cyst with consequent spillage of its contents during the surgery followed by continuous production of keratin is also suggested as a mechanism of recurrence. The recurrence may occur at the site of the original tumor or some distance away from it where the spillage may have occurred. Rupture and subarachnoid dissemination are rare in epidermoid tumors, whereas it may be seen relatively more frequently in dermoid tumors. Spread of an intracranial epidermoid into the spinal canal has hitherto not been identified in the literature.

Our patient initially presented with a fourth ventricular tumor where a radical excision of the epidermoid was performed. However, postoperatively he developed a cerebrospinal fluid (CSF) leak, which was managed with lumbar drainage. He again presented after 15 years with a recurrent tumor in the fourth ventricle and another tumor in the cervical spinal canal. We speculate that epidermoid flakes from the fourth ventricle entered the cisterna magna through the fourth ventricular outlet foramina, and from the cisterna magna into the spinal subarachnoid space either during the surgical procedure or facilitated by the lumbar drainage.

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Conflicts of interest

There are no conflicts of interest.