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CC BY-NC-ND 4.0 · Asian J Neurosurg 2025; 20(02): 423-426
DOI: 10.1055/s-0045-1806729
Case Report

Anterior Clinoid Process Metastasis with Sudden Loss of Vision: Role of Emergency Optic Nerve Decompression

Marta Rico Pereira
1   Department of Neurosurgery, Hospital Sant Pau, Barcelona, Spain
2   Institut d'Investigació Biomèdica Sant Pau, Sant Quintí, Barcelona, Spain
,
Fernando Muñoz Hernández
1   Department of Neurosurgery, Hospital Sant Pau, Barcelona, Spain
2   Institut d'Investigació Biomèdica Sant Pau, Sant Quintí, Barcelona, Spain
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Funding None.
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Abstract

Anterior clinoid process metastases are rare. We present an unusual case of anterior clinoid process metastasis with sudden deterioration of visual function requiring emergency optic nerve decompression, resulting in recovery of visual function. The patient was a 41-year-old man with a diagnosis of leiomyosarcoma of the radius, operated on in 2014, with bone and lung metastases, who had been treated with chemotherapy and appeared to have stable disease at his last follow-up. Six years later, he developed a 1-month history of progressive unilateral loss of visual acuity and visual field defect (initially quadrantanopia that progressed to nasal hemianopia). Brain imaging showed a contrast-enhancing lesion affecting the left anterior clinoid process with extension to the cavernous sinus and sphenoid sinus, causing compression of the left optic nerve. Although the lesion could have suggested a meningioma given the location, in the context of the patient's oncological history, the diagnosis of metastasis was considered more likely. The patient was admitted to the hospital and, during the hospital stay, developed sudden left retro-orbital pain progressing to left amaurosis over approximately 8 hours. Urgent surgery was performed: a pterional craniotomy with partial tumor removal and optic nerve decompression with extradural anterior clinoidectomy. After surgery, the patient had an immediate but partial improvement in visual acuity and in the visual field defect. Metastasis to the anterior clinoid process is very uncommon, with only one case previously reported in the literature. In cases of visual impairment, symptoms may deteriorate rapidly to complete loss of vision, so urgent decompressive surgery of the optic pathway may be indicated to recover visual function, although recovery may be partial.


 

Keywords

anterior clinoid process - skull base metastasis - anterior clinoidectomy - visual loss - optic nerve

Introduction

The anterior clinoid process (ACP) is an important bone structure due to its close relation to the optic nerve and the internal carotid artery (ICA). Lesions growing in the ACP may present with loss of visual acuity (VA) and visual field defects caused by compression of the optic nerve.

The most frequent lesion affecting the ACP is meningioma; others, such as mucocele and fibrous dysplasia, have also been described. Only one case of single metastasis related to the ACP has been previously published.

Sudden visual impairment is usually secondary to other types of injury, such as eye trauma. No cases of sudden visual impairment secondary to tumors have been described previously.

Surgery is the treatment of choice for ACP lesions. Clinoidectomy, either extradural or intradural, and via a pterional craniotomy, is the most common surgery. Different approaches have been described for the ACP resection, all of them based on drilling the pterion, the lesser wing of the sphenoid bone, and, finally, the ACP. The endoscopic endonasal approach is not suitable for the removal of ACP lesions since part of the ACP is located above the optic nerve, making access difficult through this route.


 

Case Report

A 41-year-old man was diagnosed with high-grade leiomyosarcoma of the radius, and operated on in 2014. He received adjuvant chemotherapy (epirubicin and ifosfamide) and radiotherapy in 2015. In 2018, multiple metastatic involvement of the axillary lymph nodes and lungs was detected. He restarted chemotherapy with gemcitabine and Dacarbazine in June 2018. He was later diagnosed with liver metastases, and a right hepatectomy and resection of metastases were performed in September 2019. The most recent computed tomography (CT) scan in December 2019 showed a decrease in pulmonary nodules with no evidence of liver disease, with apparent overall stability.

In January 2020, the patient presented with progressive loss of VA in the left eye and a visual field defect (lower nasal quadrantanopia that progressed to nasal hemianopia). CT and magnetic resonance imaging (MRI) of the brain showed two extra-axial lesions: a left frontotemporal lesion measuring 16 × 10 mm and another one in the left cavernous sinus with extension to the optic canal and rupture of the lateral wall of the sphenoid sinus. Both lesions were suggestive of metastases in the context of the patient's history ([Figs. 1] and [2]).

Zoom
Fig. 1 (A, B) CT scan axial plane. Anterior clinoid process (ACP) lesion is observed. The intracanalicular portion of the optic nerve and cavernous and ophthalmic internal carotid artery (ICA) are encased by the tumor.
Zoom
Fig. 2 (A–C) MRI T1 sequence with gadolinium. Axial and coronal planes. We can observe two extra-axial lesions: a left frontotemporal lesion measuring 16 × 10 mm and another one in the anterior clinoid process (ACP) and left cavernous sinus with extension to the optic canal and rupture of the lateral wall of the sphenoid sinus (20 × 13 mm axial plane). Both lesions were suggestive of metastases in the context of the patient's history.

During his admission, a positron emission tomography and CT (PET-CT) scan was performed, showing progression of the neoplastic disease with spread and growth of the preexisting lesions. Given that the patient had a likely prognosis for survival of greater than 6 months, it was decided in a multidisciplinary session to operate on the ACP metastasis, with the goal of partial resection and decompression of the left optic nerve, followed by adjuvant radiotherapy and chemotherapy.

The patient, while waiting for scheduled surgery in 5 days, developed sudden-onset left retro-ocular pain leading to complete loss of vision in the left eye over a period of around 8 hours. After discussion with the patient, it was decided to perform emergency surgery to try to decompress the optic nerve and recover his vision.

Surgical Procedure

The patient underwent urgent surgery via a pterional craniotomy. This approach was chosen to allow access to both metastases: the ACP lesion and the small frontotemporal lesion.

After craniotomy, the pterion was drilled, exposing the orbit and the meningo-orbital band (MOB). The MOB was cut, allowing visualization of the epidural portion of the tumor, from which biopsies were taken. Part of the lateral and superior orbital wall was removed. As the optic nerve anatomy had been distorted by infiltration of the ACP tumor, it was decided to perform a combined extradural–intradural approach to avoid damage to the optic nerve. After opening the dura, the sylvian fissure was dissected to expose the optic nerve and the ICA. The tumor occupied the entire ACP, displacing the optic nerve superiorly. The dura was opened in the direction of the optic nerve to allow intradural (as well as extradural) access to the lesion. The optic nerve was debulked and subsequently decompressed and the falciform ligament was opened. The distal dural ring of the ICA was opened and the tumor in the clinoid segment of the ICA was resected. The rest of the tumor that extended to the cavernous sinus and the sphenoid sinus was left unresected. The frontal dura was opened to remove the 1-cm lesion attached to the frontal dura. Dural substitute plus autologous periosteum and fibrin sealant were used to reconstruct the dura.

The pathology report described high-grade leiomyosarcoma metastasis, compatible with known bone primary, with positive immunohistochemical staining for α actin and caldesmon. Focal desmin stain was positive.


 

Postoperative Period

The patient had immediate improvement in VA in the left eye (VA: 0.4) and partial improvement in the visual field defect. Postoperative brain MRI showed postoperative changes with complete removal of the frontotemporal lesion and partial resection of the ACP lesion. Specifically, a decrease in the component adjacent to the lesser wing of the sphenoid, optic canal, and optic nerve was observed, with satisfactory optic nerve decompression ([Fig. 3A-3B]).

Zoom
Fig. 3 (A, B) postoperative MRI T1 sequence with gadolinium, axial plane. CT scan axial plane. We can observe partial resection of the anterior clinoid process (ACP) lesion, showing specifically a decrease in the component adjacent to the lesser sphenoid wing, optic canal, and optic nerve, with satisfactory optic nerve decompression after extradural clinoidectomy.

The multidisciplinary committee decided to perform holocranial radiotherapy plus second-line palliative chemotherapy with trabectedin.

Currently, the patient is neurologically stable; he has residual left hemianopia with a stable VA of 0.4.

During his current treatment course, he has had cutaneous disease progression, with no evidence of further intracranial progression, and stability of the other extracranial metastases.


 

 

Discussion

Leiomyosarcoma Metastases

Sarcomas are malignant tumors originating from mesenchymal cells, a heterogeneous group with different clinical, radiological, and histological characteristics. Soft tissue sarcomas constitute approximately 0.7% of all malignant tumors in adults. Histologically, three main types are described: liposarcomas, leiomyosarcomas, and malignant schwannomas.

Leiomyosarcoma represents 7 to 10% of all soft tissue sarcomas. They are mostly located in the retroperitoneum, genitourinary tract, and extremities. Primary bone leiomyosarcoma is a very rare type of sarcoma (<0.7% of malignant bone tumors). It shares similar histological characteristics with other leiomyosarcomas, but the behavior and prognosis are different, as it is normally an aggressive tumor.[1]

Leiomyosarcomas present predominately in adulthood, between the fifth and sixth decades of life. Risk factors include immunosuppression, previous radiotherapy, and the use of chemical carcinogens such as arsenic and tamoxifen. Among the general characteristics of leiomyosarcomas are their aggressiveness, difficult treatment with a high recurrence rate, and the capacity for local and distant metastasis.

Metastatic disease can present early in the course of the disease, usually during the first year. The most frequent site of metastasis is the lung, followed by the axial skeleton. Other possible locations are the liver, adrenal glands, kidney, and lymph nodes, but with a low incidence.

Sarcoma metastases in relation to the skull and, specifically, to the cranial base are very rare, with very few, isolated reports in the literature: a single case of mediastinal leiomyosarcoma metastasis in the cranial vault[2] and one case of myxoid liposarcoma metastasis in the cranial base[3] have been described. Cranial base metastases from primary bone leiomyosarcoma have not been previously described; the case we present here, to our knowledge, is the first of this type.


 

Anterior Clinoid Process Metastasis

Upon a review of the literature, metastatic disease in the ACP has only been reported in one article. In that case, secondary to male breast cancer, it presented with symptoms of progressive altered visual function and diplopia in relation to compression of the third cranial nerve (CN III).[4]

The most common lesions in the ACP are meningiomas, followed by mucoceles. Other rarely described lesions in this location include cavernous hemangiomas, fibrous dysplasia, pilocytic astrocytoma, dermoid cysts, and sarcoidotic necrotizing granulomas, among others.

The ACP is a pyramid-shaped bony process with a triangular and anterior base, located between the anterior and middle cranial fossae delimiting the sellar region. Its medial aspect lies close to the ICA, the ophthalmic artery, and the optic nerve. Inferiorly it is in close relation to the roof of the cavernous sinus and the oculomotor nerve (CN III). At its apex, the free edge of the tentorium, the interclinoid ligament, and the carotid–clinoid ligament insert. These last two can be found completely ossified, forming clinoid bridges, or partially ossified, forming spicules.

Anterior clinoidectomy is a key surgical procedure for the treatment of ICA and ophthalmic aneurysms, and an important tool in skull base surgeries. It was initially described by Dolenc for the treatment of vascular lesions in relation to the cavernous sinus. Likewise, it is essential in the excision of neoplastic lesions in this location. The primary goals of clinoidectomy are exposure of the proximal ophthalmic and clinoid segments of the ICA and skeletonization of the optic nerve. With this procedure, the optic–carotid and carotid–oculomotor windows are widened to allow a wide release of the optic nerve, which can be mobilized safely.

This technique can be performed intradurally or extradurally. The extradural technique has a series of advantages over the intradural technique. Anatomical orientation is easier with identification of the superior orbital fissure and optic canal, allowing total clinoidectomy and greater exposure of the optic nerve. In addition, the intradural structures are protected. In the case of metastatic disease such as the case presented here, it also minimizes the risk of disease spread to the subdural space during the intervention.

As commented previously, anterior clinoidectomy allows a wide decompression of the optic nerve, constituting a key maneuver in certain pathologies involving optic nerve compression, such as tumors in the region. Compression of the optic nerve due to tumors, mainly meningiomas, in relation to the ACP, cavernous sinus, sphenoid wing, and tuberculum sellae, usually produces a progressive loss of visual function.[5] The only option for recovery and/or preservation of function in these cases is to perform anterior clinoidectomy.

In our case, after extensive decompression of the optic nerve by means of extradural anterior clinoidectomy, the visual function showed an almost immediate improvement (recovery of VA from amaurosis to 0.4).

The sudden onset of such a visual deficit is very rare. Generally, sudden alteration of visual function due to compressive pathology of the optic nerve is produced by trauma affecting the nerve at any of its segments, including the optic canal. In these cases, surgery in the first 12 to 24 hours usually gives good functional results and is performed via an endoscopic endonasal approach and intracanalicular nerve release.[6] [7]

Returning to metastatic disease of the ACP, as previously mentioned, only one case has been previously reported in the literature, to the best of our knowledge. Our case report represents the second case of ACP metastasis but is the first case involving sudden loss of vision. Likewise, it constitutes the first case of primary bone leiomyosarcoma metastasis to the skull base.


 

 

Conclusion

Metastatic tumor pathology must be considered in the diagnosis of ACP lesions. Extradural anterior clinoidectomy is a key procedure to try to preserve visual function in these cases.


 

 

Conflict of Interest

None declared.

Patients' Consent

The patient has consented to the submission of the case report for submission to the journal.



Address for correspondence

Marta Rico Pereira, MD
Department of Neurosurgery, Hospital Santa Creu i Sant Pau
Carrer de Sant Quintí, 89. 08041, Barcelona
Spain   

Publication History

Article published online:
24 March 2025

© 2025. Asian Congress of Neurological Surgeons. This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/)

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Zoom
Fig. 1 (A, B) CT scan axial plane. Anterior clinoid process (ACP) lesion is observed. The intracanalicular portion of the optic nerve and cavernous and ophthalmic internal carotid artery (ICA) are encased by the tumor.
Zoom
Fig. 2 (A–C) MRI T1 sequence with gadolinium. Axial and coronal planes. We can observe two extra-axial lesions: a left frontotemporal lesion measuring 16 × 10 mm and another one in the anterior clinoid process (ACP) and left cavernous sinus with extension to the optic canal and rupture of the lateral wall of the sphenoid sinus (20 × 13 mm axial plane). Both lesions were suggestive of metastases in the context of the patient's history.
Zoom
Fig. 3 (A, B) postoperative MRI T1 sequence with gadolinium, axial plane. CT scan axial plane. We can observe partial resection of the anterior clinoid process (ACP) lesion, showing specifically a decrease in the component adjacent to the lesser sphenoid wing, optic canal, and optic nerve, with satisfactory optic nerve decompression after extradural clinoidectomy.