Epidermoid Cyst with Torcular Herophili Obstruction and Unusual Venous Drainage

Evaluating diploic vein blood flow using time-resolved whole-head computed tomography angiography and determining the positional relationship between typical craniotomy approaches and diploic veins in patients with meningioma

BACKGROUND

Diploic veins may act as collateral venous pathways in cases of meningioma with venous sinus invasion. Diploic vein blood flow should be preoperatively evaluated to consider preserving the veins. In this study, we evaluated the use of time-resolved whole-head computed tomography angiography (4D-CTA)-which is less patient-intensive than digital subtraction angiography (DSA)-for assessing diploic vein blood flow and the positional relationship between typical craniotomy approaches and diploic veins.

METHODS

We retrospectively examined 231 patients who underwent surgery for intracranial meningioma. We performed contrast-enhanced magnetic resonance imaging (MRI) to evaluate diploic vein pathways and compared the visualization rates of diploic vein blood flow assessed using 4D-CTA and DSA. Subsequently, we evaluated the rates of the diploic veins transected during craniotomy by comparing the pre- and postoperative contrast-enhanced MRI.

RESULTS

The diagnostic performance of 4D-CTA was assessed in 45 patients. Of the 320 diploic veins identified in these patients, blood flow in 70 (21.9%) diploic veins was identified by 4D-CTA and DSA, and both results were consistent. To assess the transection rates of the diploic veins, 150 patients were included. A trend towards a high transection rate of the diploic vein in the basal interhemispheric, frontotemporal, orbitozygomatic, combined transpetrosal, and convexity craniotomy approaches was observed.

CONCLUSIONS

In patients with meningiomas, both 4D-CTA and DSA are useful in evaluating diploic vein blood flow. In meningiomas with venous sinus invasion, determining the extent of craniotomy after understanding the pathways and blood flow of diploic veins is recommended.

Diploic veins as collateral venous pathways in patients with dural venous sinus invasion by meningiomas

BACKGROUND

Although it is known that diploic veins frequently communicate with the dural venous sinuses, the role of diploic veins in patients with venous sinus invasion from meningiomas remains unknown.

METHODS

We retrospectively examined the medical records of 159 patients who underwent their first craniotomies for intracranial meningiomas. Contrast-enhanced magnetic resonance imaging was used to evaluate diploic vein routes, and digital subtraction angiography (DSA) was used to evaluate diploic vein blood flow. When high blood flow was visualized concurrently with the venous sinuses, the veins were classified as of the "early type." Diploic vein routes were classified into five routes.

RESULTS

DSA was performed in 110 patients, with 14 showing superior sagittal sinus (SSS) invasion (SSS group) and 23 showing non-SSS venous sinus invasion (non-SSS group). The proportion of early type diploic veins was significantly higher in the SSS group (27.1%) than in other patients (patients without venous sinus invasion, 2.1%; non-SSS, 4.3%) (p < 0.01). In patients not in the SSS group, diploic veins were sacrificed during craniotomy in 76 patients, including four patients with veins of the early type. No patients demonstrated new neurological deficits postoperatively. In the SSS group, diploic veins were sacrificed in all patients, and early type diploic veins were cut in five patients. Two of these five patients showed postoperative neurological deficits.

CONCLUSIONS

In the SSS group, diploic veins may function as collateral venous pathways, and attention is recommended for their interruption. In patients without SSS invasion, diploic veins, even of the early type, can be sacrificed.

Acute-onset diplopia from intracranial hypertension due to torcular herophili obstruction by an hemorrhagic intradiploic epidermoid cyst

BACKGROUND

Epidermoid cysts are benign slow-growing congenital lesions, constituting approximately 1% of all cranial tumors. Most of these lesions are located intradurally, while about 10-25% of them are located within the diploic spaces. Intradiploic epidermoid cysts are usually discovered incidentally and may remain asymptomatic for many years, but in rare instances, they may grow intracranially and produce brain compression. Sometimes, intradiploic epidermoid cysts may occlude the main cranial venous sinuses causing intracranial hypertension.

CASE DESCRIPTION

We present the case of a 24-year-old male harboring a paramedian right occipital intradiploic cyst with erosion of both outer and inner bony tables, which occluded the torcular herophili producing a worsening symptomatology with acute-onset diplopia from right sixth cranial nerve palsy; the patient also presented bilateral papilledema, but only reported mild headache and dizziness. Neuroradiological studies evidentiated a lesion compatible with intradiploic epidermoid cyst with intralesional hemorrhagic component, overlying and almost completely occluding the torcular herophili. Considering the fast worsening of symptomatology and the evidence of intracranial hypertension, the patient was operated on immediately after completion of clinical and radiological assessment. The lesion was radically removed with almost immediate reversal of signs and symptoms. Histopathology confirmed the diagnosis of epidermoid cyst with intralesional hemorrhagic components.

CONCLUSION

Intradiploic epidermoid cysts may cause intracranial hypertension by occlusion of main cranial venous sinuses; intralesional hemorrhage may act as precipitating factor in occlusion of the torcular herophili, producing rapidly worsening intracranial hypertension, which requires prompt surgical treatment to reverse symptomatology. Radical surgical resection is necessary to avoid recurrence.

Venous hypertension caused by a meningioma involving the sigmoid sinus: case report

Background

Intracranial venous hypertension has been associated with a few cases of meningioma secondary to compression of the venous sinus. This is the rare case of small meningioma involving the sigmoid sinus leading to intracranial venous hypertension mimicking venous thrombosis.

Case presentation

A 39-year-old woman suffered visual dysfunction due to bilateral papilledema. Noncontrast head computed tomography (CT) showed no intracranial space-occupying lesions or hydrocephalus. Cerebrospinal fluid examination revealed high opening pressure. Various image inspections such as three-dimensional CT angiography, magnetic resonance imaging, and cerebral angiography demonstrated a small 2.5-cm lesion causing subtotal occlusion of the dominant right sigmoid sinus. No improvement of clinical manifestations was observed after medical treatment for 6 months, so right presigmoid craniectomy was performed. Operative findings revealed that the tumor was located predominantly involving the sigmoid sinus. The pathological diagnosis was fibrous meningioma. Postoperative fundoscopic examination showed improvement of bilateral papilledema.

Conclusions

We treated a patient presenting with intracranial hypertension due to a small meningioma involving the sigmoid sinus. This unusual case suggests that early surgical strategies should be undertaken to relieve the sinus obstruction.