Endoscopic Endonasal Treatment of a Large Clival Giant Cell Tumor Invading the Cavernous Sinus and Temporal Lobe

ABSTRACT

Giant cell tumors (GCTs) are extremely rare lesions, representing less than 5% of all bone tumors. They primarily occur in the long bones. However, a small percentage of these tumors occur in the pelvis, spine, or skull bones. These lesions are usually benign as well as locally aggressive and require complete removal. Nowadays, GCT and other skull base lesions can be treated using the extended endoscopic endonasal approach.We present a case report of a GCT located in the skull base, originating from the clivus and sphenoid bone, invading through the cavernous sinus, and treated using the fully endoscopic endonasal approach.

Key Words:Giant cell tumor, sphenoid sinus, clivus,cavernous sinus

Primary giant cell tumors (GCTs) mainly originate in the metaphyseal region of long bones in the appendicular skeleton.1 Giant cell tumors usually show benign behavior; however, they can be locally aggressive, and in some cases, malignant transformation or metastatic disease occurs.2,3 They account for approximately 5% of all primary bone tumors.2 Although most of these tumors are located in the long bones of the extremities, a small proportion (G10%) occurs in the pelvis, spine, or skull base.2,3 Several reports of paranasal sinus GCT have been published, but skull base locations with cranial invasion for these tumors are exceedingly rare.4,5 Usually, patients present with small lesions after a brief history of swelling or pain, but especially in the sacral region, tumors can reach an aberrant size and cause severe neurologic deficits.6 Recommendations for treating these lesions are still unclear, and the role of surgery, as well as adjuvant therapies, remains undefined. 7,8 Complete tumor removal and drilling of the surrounding healthy bone are preferable to expect a clinical cure and to reduce recurrence rate.9 The recommended treatment of GCTs is functionpreserving surgery.10 After complete resection, local control is achieved in 85% to 90% of all cases, but incomplete resection is frequently associated with tumor recurrence in up to 50% of the cases.10,11 If these tumors occur in the skull base, surgical treatment can be difficult; therefore, the use of adjuvant therapy is important in nonoptimal management.10 Today, GCTs, as well as other lesions located in the sphenoid sinus and clivus, can be treated using an extended endoscopic endonasal approach (EEA) safely and effectively.9 This approach gives a more direct route with better visualization to the craniovertebral junction than that of other possible approaches. In this report, we present the management of a large sphenoid sinus mass using the extended EEA. The clivus was eroded, and the sella was elevated by the tumor, which also invaded into the cavernous sinus and extended into intracranial space. This case is ncommon and valuable because it demonstrates a primary skull base GCT that intruded into the intracranial space and caused cranial nerve palsy

CLINICAL REPORT

A 27-year-old woman was admitted to our clinic because of progressive headache and diplopia for 1 year. Her physical examination revealed a good general state of health. In neurologic assessment, she had full cooperation and orientation with both normal motor and sensory examinations but had a left sixth cranial nerve palsy and double vision in the left lateral gaze. Examination findings for other cranial nerves, including visual field and acuity, were also normal. A paranasal computed tomographic scan revealed a soft tissue mass filling the sphenoid sinus as well as destroyed clivus and sellar floor, extending into the left cavernous sinus and growing into the left temporal lobe (Fig. 1). A 3.2
4.4
5.1-cmYsized expansive mass lesion, originating primarily from the left sphenoid sinus and clivus as well as enhancing heterogeneously with contrast, was detected with a cranial magnetic resonance imaging (MRI). The tumor destroyed clivus, sellar floor, and ethmoidal cells, filled in the anterior skull base completely including the left cavernous sinus and sella and extended into the left temporal lobe (Fig. 2).An extended EEAwas preferred for the surgical treatment. A binostril approach was performed, and the tumor was exposed right after the left middle turbinate excision. The tumor was removed completely with the surrounding healthy bone for negative margins using pure EEA. Cerebrospinal fluid leakage occurred during the tumor removal, and a multilayer reconstruction was performed with autologous fat tissue and fascia lata grafts and by using fibrin sealant. The postoperative cranial MRI revealed an almost gross-total excision of the tumor (Fig. 3). Nasal tampon was not preferred after the operation. The patient was discharged 4 days after the operation without any newly emerging neurologic deficit. Histopathologic examination revealed a GCT, demonstrating well-vascularized tissues uniformly consisting of plump, spindly, or ovoid undifferentiated stromal cells, with numerous large multinucleated giant cells (Fig. 4). Brain MRI was performed regularly 3 and 6months after the operation. The patient has received stereotactic radiotherapy 3 months after the operation. She was asymptomatic (except the left sixth nerve palsy) and did not present any relapse of the disease since 6 months of follow-up.

DISCUSSION

Neoplasms of the nasal cavity and paranasal sinuses account for 0.2% to 0.8% of all cancers.12 Primary sphenoid sinus masses are quite unusual; however, they represent only 2% to 3% of paranasal sinus neoplasms.13 Primary GCTs of the sphenoid sinus are extremely rare lesions; they are known to constitute 3% to 7% of all primary bone tumors from only some case presentations in the literature. 14 They are rarely seen before the closure of the epiphyseal plates and mostly occur in the epiphyseal-metaphyseal junctions of long bones.14 A small proportion (G10%) of these tumors occurs in the pelvis, spine, or skull base.2,3 Cranial GCTs have a tendency for skull involvement, most commonly the sphenoid bone, followed by the petrous portion of the temporal bone.15,16 Also, GCTs of the craniospinal axis are very rare and present with a localized lesion with bone lysis. Typical clinical presentation is pain or neurologic deficit because of the involved region of the bone.17 Frontal headaches, diplopia, proptosis, and visual disturbances are other frequent symptoms in the cases with sphenoid bone involvement, which were also observed in our patient as well. A typical presentation of patients with GCTs involving the skull base has previously been defined by Watkins et al.16 The patients have headache, ocular palsy, and visual loss with erosion of the body of sphenoid but with normal endocrine functions. This typical appearance is in concordance with our young patient. We present the management of a rare sphenoidal sinus GCT case that eroded the clivus and invaded into the cavernous sinus and intracranial space. Giant cell tumors are usually benign tumors, but they can be locally aggressive and they tend to recur. In some cases, GCT shows malignant transformation and metastasis.2,3 The standard management for GCTs is function-preserving surgery. After complete resection, local control is achieved in 85% to 90% of all cases, but incomplete resection is frequently associated with tumor recurrence in up to 50% of the cases.3,6 Treatment for typical GCT of the long bones is generally well defined, and a wide surgical excision is generally preferred to reduce the risk for local recurrence.7 However, complete surgical removal of GCTs originating in the skull base is typically not possible and GCTs also require the resection of the surrounding apparently healthy bone.18 Surgery for the sphenoidal sinus and clivus was described before as extended lateral, posterolateral, and anterior approaches. All of these traditional approacheshave the same big disadvantage as a risk for cranial nerve or carotid artery injury with cosmetically disfiguring results. At the same time, the sublabial or endonasal microscopic approaches provide a narrow corridor that limits the view of the microscope.19 Nowadays, EEA is the first choice for the management of the sphenoid sinus and clivus lesions. Advantages of EEA is the ability to access natural corridors under improved visualization and magnification by moving the lens and the possibility to look laterally using angled endoscopes, which provides access to the clivus without manipulating critical neurovascular structures.19,20 In our report, a large skull base GCT extending into the intracranial space was treated using an extended EEA. The lesion was removed almost completely, and the surrounding bonewas adequately drilled for negative margins without any complications. At present, no universal standard treatment modality exists for these tumors; however, there are considerable data regarding the effectiveness of radiation therapy. A dose between 50 and 60 Gy to the sphenoid sinus and surrounding tissues in a fractionated or hyperfractionated stereotactic fashion seems appropriate.2,12,13 Therefore, our patient received stereotactic radiotherapy (dose range, 50Y60 Gy) to reduce the recurrence of the tumor 3 months after the operation. There were no newly developed symptoms or any relapse of the disease since 6 months of follow-up.

CONCLUSIONS

Skull base GCTs are uncommon lesions that can now be safely and completely removed using a minimally invasive, fully extended EEA. Treatment of these rare skull base tumors requires a multidisciplinary approach. However, long-term follow-up is required in this case to conclude for the final outcome.