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 Table of Contents  
ORIGINAL ARTICLE
Year : 2020  |  Volume : 18  |  Issue : 3  |  Page : 295-301

Surgical management of sphenoid ridge meningioma en plaque (spheno-orbital meningioma)


Department of Neurosurgery, Faculty of Medicine for Girls, Al-Azhar University, Cairo, Egypt

Date of Submission14-Jan-2020
Date of Decision11-May-2020
Date of Acceptance02-Jun-2020
Date of Web Publication30-Oct-2020

Correspondence Address:
Gasser Hasan Al-Shyal
Department of Neurosurgery, Al-Azhar University Faculty of Medicine for Girls, Al-zahraa Hospital, Abbassya, Cairo
Egypt
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/AZMJ.AZMJ_5_20

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  Abstract 


Background and aim The aim of the study was to investigate the surgical techniques to remove meningioma en plaque and to compare our technique and results with other authors.
Patients and methods This retrospective series case was done at our University Hospital. Eight patients were managed at Al-Zahraa University Hospital between March 2016 and March 2018. Preoperative and postoperative clinical and radiological assessments were done for each patient.
Results There were eight patients in our study. All patients are women. The age range was from 34 to 60 years and the mean was 45.4 years. Proptosis was the main clinical manifestation and it was present in all eight patients. Three (37.5%) patients had visual impairment while two (25%) of them had headache and retro-orbital pain. We achieved total resection in six (75%) out of our eight patients. All tumors were WHO grade 1 meningiomas. Regarding surgical outcome, proptosis improved in six (75%) of the eight cases. Visual impairment improved in two (66.7%) cases out of three who had visual declination preoperatively.
Conclusion Meningioma en plaque can be safely removed without any morbidity or mortality. Proptosis and hyperostosis in the sphenoid bone are highly suggestive and this requires more accurate radiological studies. MRI with contrast is essential for these cases. Extensive bony drilling is required for gross total resection. It also facilitates resection of the soft part of the tumor with its dura. Some cases may need orbital wall reconstruction. Proptosis mostly improves after surgery.

Keywords: meningioma, proptosis, pterional approach, skull base, sphenoid wing meningioma, spheno-orbital meningioma


How to cite this article:
Al-Shyal GH, Mohamed MS, Eissa MF. Surgical management of sphenoid ridge meningioma en plaque (spheno-orbital meningioma). Al-Azhar Assiut Med J 2020;18:295-301

How to cite this URL:
Al-Shyal GH, Mohamed MS, Eissa MF. Surgical management of sphenoid ridge meningioma en plaque (spheno-orbital meningioma). Al-Azhar Assiut Med J [serial online] 2020 [cited 2020 Nov 25];18:295-301. Available from: http://www.azmj.eg.net/text.asp?2020/18/3/295/299571




  Introduction Top


Meningioma accounts for about one-third of the primary brain tumors [1]. The term meningioma en plaque (MEP) was first described by Cushing [2], which is flat soft tumor that infiltrates the dura [3]. It invades the bone causing hyperostosis. This occurs mostly along the sphenoid wing [4]. Two synonyms are used for the description of these tumors: MEP and spheno-orbital meningiomas [5],[6],[7],[8].

These tumors are slowly growing, and it has either flat or slightly nodular shape [9]. MEPs are more likely to cause bony hyperostosis than are larger globular tumors and the amount of hyperostosis is often disproportionate to the relatively small tumor [10],[11],[12].

Hyperostosis may extend in the skull base involving the lateral and superior orbital walls of the optic canal and the anterior clinoid process. The dural growth is usually extensive and may include the basal sphenoid wing, cavernous sinus, and temporal convexity. Hyperostosis may result in compression of the optic nerve and or other cranial nerves. Also, it causes proptosis, visual deterioration, and cosmetic deformity [13],[14].

Proptosis is the most common presentation of MEP. It is unilateral, nonpulsating, and irreducible. Other manifestations include decreased visual acuity, headache, and limitation of extraocular muscle movements. Less frequently, swelling in the temporal region, seizure, and facial pain are seen [15].

Differential diagnosis of these lesions is meningeal sarcoidosis, osteoma, tuberculoma, and fibrous dysplasia [16],[17]. Choosing surgical approach and strategy for removal of MEP are challenging, because it has extensive orbital, bone, and dural involvement [18],[19],[20],[21]. As a result, MEP has relatively high recurrence rate than other types of meningioma [22]. However, with the development in microsurgical technique and craniofacial approaches it is possible to be more radical in the management of these tumors and many surgeons reported favorable outcomes [15],[23],[24],[25]. In our opinion, extensive bony drilling of the affected bone and good exposure of the soft tumor mass is the key to achieving favorable surgical outcomes.


  Patients and methods Top


This retrospective study was conducted at Al-Zahraa University Hospital, after approval from the local ethics committee and after written informed consent was obtained from each patient before surgery. Eight patients were managed at Al-Zahraa University Hospital in the interval between March 2016 and March 2018. We reviewed the preoperative clinical assessment for each patient. We did ophthalmology consultation for each patient to access their visual acuity.

We did both MRI and computed tomography (CT) bone window (with 3D reconstruction) for every patient. We reviewed the preoperative images to access the location of the tumor, the site of hyperostosis, and to plan our surgical techniques.

Axial and coronal CT scan images of the bone window were essential for visualization of hyperostosis. We found that contrast is essential for detecting the dural enhancing component of these lesions. In one of our cases, the lesion did not appear except in contrasted MRI. Large axial orbital cuts increase the sensitivity of picking up small dural enhancement.

We did pterional craniotomy for all eight cases. Care was taken to avoid injury of the frontal branch of the facial nerve. In some patients, we removed the soft tumor that infiltrated the temporalis. After removal of the extracranial component of the tumor and separation of temporalis, a high-speed drill was used for removal of hyperostotic bone of the lesser and greater sphenoid wings. In two cases, we flattened the marginal tubercle (elevation of the posterior border of the zygomatic process of the frontal bone) to get good exposure of the lateral wall of the orbit and the anteroinferior part of the greater sphenoid wing ([Figure 1]). Then, the remaining part of the bone is elevated. We continued drilling of the pathological bone of sphenoid wings and roof of the orbit. The optic canal was opened to decompress the optic nerve in cases with marked hyperostosis in the optic canal. If there was orbital infiltration, tumor in the orbit was followed and removed. We did not remove any tumor part infiltrated superior orbital fissure dura to avoid cranial nerve deficits. The blood supply MEP usually arises from branches of the middle meningeal artery. We got good devascularization of the tumor by cauterizing these branches after resection of the sphenoid wing with hyperostotic bone. Soft tumors are removed with the dura. The excised dura is replaced with the artificial substitute. We removed the affected bone to avoid recurrence and this leads to defects in lateral and/or roof of the orbit. We used a titanium mesh plate to replace drilled bones in the temporal fossa, but we did not reconstruct the superior wall of the orbit. All cases were examined in the same day after surgery and were followed up for 1 year. Follow-up imaging (CT bone window and MRI) to access residual and recurrent tumors was done after 6 months and 1 year.
Figure 1 Increasing exposure with marginal tubercle drilling. Arrow points to the marginal tubercle: (a) before drilling and (b) after drilling.

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Statistical analysis

The study is an observational retrospective case series study and descriptive statistics was used as follows:
  1. Quantitative data: mean and SD were used to measure central tendency and dispersion.
  2. Qualitative data: the studied variables were analyzed using univariant analysis and presented as frequencies and percentages (frequency distribution table) for qualitative variables.



  Results Top


There were eight patients in our study. All patients are women. The age range was from 34 to 60 with a mean age of 45.4 years ([Table 1]).
Table 1 Summary of patients with meningioma en plaque

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Clinical manifestations

Proptosis was the main clinical manifestation and it was present in all eight patients. One patient had bilateral exophthalmos due to toxic goiter and the tumor was accidently discovered after doing MRI on the orbits in the Ophthalmology Department. Three (37.5%) patients had visual impairment while two (25%) of them had headache and retro-orbital pain.

Resection, pathological grading, and reconstruction

Gross total resection was done for six (75%) out of eight patients ([Figure 2]). In one of the other two patients, we left the part invading the dura of the superior orbital fissure and the residue did not increase in size within the follow-up period. In another one, we left a piece of the tumor that was closely adherent to the optic nerve. It showed increasing size during the follow-up. There was no recurrence for all cases after total excision of the tumor. All tumors were WHO grade 1 meningiomas. In three (37.5%) cases, we used titanium mesh to reconstruct the lateral wall of the orbit and the temporal fossa ([Figure 3]).
Figure 2 Preoperative and postoperative radiological images of left sphenoid wing MEP: (a) preoperative MRI axial T1 images showing dural enhancement of the sphenoid wing, (b) postoperative axial images showing removal of the enhancing lesion in the middle cranial fossa, (c) postoperative axial CT bone window showing removal of hyperostotic bone without reconstruction. CT, computed tomography; MEP, meningioma en plaque.

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Figure 3 (a) Preoperative MRI of right MEP, (b) postoperative MRI after excision of the enhancing mass and drilling of the hyperostotic bone, (c) preopertaive CT scan showing hyperostosis in the sphenoid bone with red arrow pointing to the marginal tubercle, (d) postoperative CT scan bone window showing reconstruction of the temporal bone with titanium mesh. CT, computed tomography; MEP, meningioma en plaque.

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Improvement in preoperative clinical manifestations

Regarding surgical outcome, proptosis improved in six (75%) out of our eight cases. Visual impairment improved in two (66.7%) cases out of three who had visual declination preoperatively.

Complications

Postoperative and follow-up periods were uneventful for five patients. Three patients have some complications. One patient suffered from severe declination of visual acuity due to traction of a piece of tumor that was very adherent to the optic nerve. Two of our patients experienced cerebrospinal fluid leak and subgaleal collection that has been improved and disappeared after 2 months. One patient has third nerve palsy while another one has injury of the frontal branch of the facial nerve.


  Discussion Top


MEP accounts for about 2–4% of intracranial meningiomas [8]. These tumors cause significant hyperostosis and a widespread, carpet-like, soft-tissue growth at the dura. Commonly, it involves the sphenoid ridge with the orbit, so it is also called spheno-orbital meningioma [4].

Some authors in the past [9] have recommended not to do surgical intervention for these tumors be considered only as a last resort because of the high surgical mortality rate. Over the years, this concept has been changed so MEP can be resected safely without or with minimum morbidity [23],[26],[27].

In all studies we reviewed, most of the patients were women [4],[5],[6],[7]. In a series done by Jesus and Toledo [8], all patients were women. We found the same regarding sex as all our patients are women. Li et al. [4] found that the mean age of MEP was 45.5 years. This is what we found in our series. The mean age was 48.3 years in a series of 37 patients studied by Oya et al. [13].

Li et al. [4] found that all cases in their series presented with proptosis and this is like what we found in our results. Oya et al. [13] found that five of his 39 patients did not have proptosis.

Visual impairment was present in two (33.3%) cases out of six in a series done by Jesus and Toledo [8]. Honeybul et al. [20] reported the same results. They found that five (33.5%) of their 15 patients had visual deterioration. Our results are not far from this, as three (37.5%) of our patients had visual impairment. Oya et al. [13] found that preoperative visual deficits were present in 53.8% of their patients.

Li et al. [4] reported that 24.3% of the studied MEP patients had headache. Similar to that retro-orbital pain and headache were present in two (25%) out of eight cases in this series. Jesus and Toledo [8] found that one case out of their six cases had headache. Honeybul et al. [20] found that 46.7% of their patients had headache. Jesus and Toledo [8] found that out of six MEP cases, one case presented with seizures.

Different surgical approaches have been reported for excision of MEP including pterional, frontotemporal-orbitozygomatic and cranio-orbital approaches [5],[6],[7],[8]. Jesus and Toledo [8] used frontotemporal craniectomy with orbital decompression for all their cases. Terrier et al. [22] used frontotemporal approach with extradural removal of the invaded or hyperostotic bone with high-speed drills and rongeurs. Oya et al. [13] reported their use of the modified Dolenc approach with extradural bone drilling. In our series, all cases were done via pterional craniotomy with extradural bone drilling.

Sandalcioglu et al. [28] did osteotomy of both upper and lateral orbital ridges to excise 81.2% of their MEP cases. We found that drilling of the marginal tubercle without orbitozygomatic craniotomy is enough to improve angles of exposure and getting direct access to the hyperostotic bone in the lower sphenoid and middle cranial fossa. Oya et al. [13] stated that orbitozygomatic approach may cause enophthalmos because it separates the periorbita from the orbital rim. They stated that reconstruction of the orbit is not necessary if the periorbita was not detached from the orbital rim.

Oya et al. [13] reported gross total resection in 38.5% of their patients with MEP, while Jesus and Toledo [8] achieved total resection in 83.3% of cases. Schick et al. [29] did total resection for 59.7% of their MEP cases. We are in the same range as we achieved total resection in 75% of our cases. Terrier et al. [22] did total resection in 40% of their MEP cases. Furthermore, they stated that their series did not show any significant difference in recurrence rate between total and partial tumor removal. We do not agree with this opinion as one of our cases with soft tumor residues showed an increase in the size after 6 months.

Li et al. [4] found that 89% of their cases were of WHO grade 1 meningioma. In a study by Sandalcioglu et al. [28], they confirmed that all his cases were WHO grade 1. Histopathological examination of all specimens in our study revealed grade 1 meningiomas.

Jesus and Toledo [8] used methyl acrylate to reconstruct the defect in the temporal bone after removal of the hyperostotic bone. They mentioned that the sphenoid ridge does not need reconstruction. We used titanium mesh to cover the bony defect in the temporal fossa and lateral wall of the orbit. Construction was done for 37.5% of our cases without any difference in cosmetic outcome. Opinion varies regarding reconstruction of the superior and the lateral orbital wall. Maroon et al. [18] reported no cosmetic problems after performing 200 cases without reconstruction. Oya et al. [13] did not reconstruct any orbital walls even after complete drilling of the roof and posterolateral walls of the orbit. Gaillard et al. [24] recommend orbital reconstruction if more than one orbital wall had been resected. We confirmed this in our study. Both superior and lateral walls were removed completely (till orbital apex) in one of our cases. Reconstruction was not enough to cover the lateral wall of the orbit. Proptosis have not been improved as a result of protrusion of the temporal tip dura in the orbit.

Proptosis represents the main clinical symptom of MEP. Jesus and Toledo [8] reported proptosis improvement in 100% of their patients. Honeybul et al. [20] reported 84.6% improvement in their MEP patients. Oya et al. [13] documented that proptosis improved in 73.5% of their cases. We are in the same range as proptosis has improved in 75.5% of our patients.

Very important goal for surgery is to improve visual acuity. Scarone et al. [30] document that visual symptoms improved in 85% of their patients. Cannon et al. [14] reported 16.6% improvement. Oya et al. [13] achieved 66.7% improvement of visual acuity in their MEP patients and we got similar result as visual symptoms improved in two of our three (66.7%) patients with preoperative visual impairment.

Visual deterioration has been reported in many literatures. In the study by Honeybul et al. [20] 26.6% of cases experienced visual deterioration after surgery. Oya et al. [13] reported no (0%) postoperative visual worsening in their MEP cases. In our series, one (12.5%) patient experienced severe visual deterioration.Regarding recurrence, our cases were followed up for 24 months (2 years) except for two cases that have been followed up for 21 months. Schick et al. [29] reported 10.4% within the 24-month follow-up period. In our series, there was no recurrence in the six cases that have been excised totally. One of our cases that has been done subtotally showed an increase in tumor size after 1 year.

Complications may occur after MEP surgery. The most common complications that has been reported are trigeminal hypoesthesia and oculomotor nerve palsy [13],[22]. Postoperative trigeminal hypoesthesia has been reported to be in 3–21% of patients [13]. Postoperative trigeminal hypoesthesia is 4.6% in a series by Terrier et al. [22]. Careful drilling with continuous irrigation around SOF, foramen rotundum, and ovale markedly decrease the incidence of this complication. In our series, we used the drill carefully around these areas; thus, our cases have not experienced trigeminal hypoesthesia. Oya et al. [13] reported 7.7% oculomotor nerve palsy after MEP surgeries. In a series by Honeybul et al. [20], they found that the incidence of oculomotor nerve affection is 6.6%. In the current series, one of our eight cases have experienced third nerve palsy. Honeybul et al. [20] reported that 7% of their cases had postoperative frontal nerve palsy. In our series, one (12.5%) patient has permanent frontal nerve injury. Two (25%) of our patients had cerebrospinal fluid collection that disappeared within 2 months after surgery. Schick et al. [29] reported that eight (11.9%) of their 67 patients had transient cerebrospinal fluid leak and were successfully treated by lumbar drainage (five patients) or puncture (three patients). In the series by Honeybul et al. [20], they document postoperative hemiplegia, DVT, pulmonary embolism, chronic subdural hematoma, and retro-orbital hematoma with 6.6% incidence for each. None of our patients experienced any of these complications.


  Conclusion Top


MEP can be safely removed without any morbidity or mortality. Proptosis and hyperostosis in the sphenoid bone are highly suggestive and this requires more accurate radiological studies. MRI with contrast is essential for these cases. Extensive bony drilling is required for gross total resection. It also facilitates resection of the soft part of the tumor with its dura. Some cases may need orbital wall reconstruction. Proptosis mostly improves after surgery.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
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