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Abducens nerve palsy as the unique sign of a trigeminal schwannoma
Clinical Neurology and Neurosurgery 115 (2013) 1121–1122
Contents lists available at SciVerse ScienceDirect
Clinical Neurology and Neurosurgery journal homepage: www.elsevier.com/locate/clineuro
Case report
Abducens nerve palsy as the unique sign of a trigeminal schwannoma Giuseppe Mariniello ∗ , Arcangelo Giamundo, Vincenzo Seneca, Francesco Maiuri Department of Neurosurgery, “Federico II” University School of Medicine, Naples, Italy
a r t i c l e
i n f o
Article history: Received 8 October 2011 Received in revised form 12 August 2012 Accepted 25 August 2012 Available online 30 September 2012 Keywords: Abducens nerve Trigeminal schwannoma Cavernous sinus Skull base tumor
1. Introduction Schwannomas of the trigeminal nerve are benign, uncommon tumors that account for 0.07–0.36% of all intracranial neoplasms and 0.8–8% of intracranial schwannomas [1,2]. They usually present with pain and paresthesia of the face as initial symptoms, whereas disturbances of the extraocular movements are observed later, coupled with trigeminal symptoms, as the result of compression of the abducens or more rarely oculomotor and trochlear nerves [1]. We report an unusual case of a trigeminal schwannoma causing an abducens nerve palsy as unique symptom, and discuss the diagnostic and therapeutic implications of this rare clinical presentation.
During operation the tumor was approached via a frontotemporal epidural approach, as described in a previous report [2]. It allowed to expose extradurally the floor of the middle cranial fossa and the rotundum, ovale and spinosum foramina. The tumor was entirely extradural and originated from the anteromedial portion of the Gasserian ganglion and the second branch of the trigeminal nerve, which were intimately adherent to the tumor. Subtotal tumor resection was achieved using the entry corridors between V1 and V2, and between V2 and V3. The abducens nerve was found to be compressed at level of its precavernous segment. Histologically the tumor was diagnosed as schwannoma. Postoperatively, progressive remission of diplopia occurred within several days. The patient experienced V2 hypaesthesia which disappeared after 1 month.
2. Case report 3. Discussion A 24-year-old woman presented a history of chronic headache. Two months before admission she experienced continuous diplopia in the left gaze. On admission the neurological examination revealed left abducens nerve palsy, whereas the pupils and the eye fundus were normal, and the trigeminal function was preserved along with the pupillar and corneal reflexes. MRI depicted a left parasellar tumor extending from the superior orbital fissure to the apex of the pyramid, with homogeneous contrast enhancement (Fig. 1a and b).
∗ Corresponding author at: Department of Neurosurgery, “Federico II” University School of Medicine, 5 Via S. Pansini, Naples 80131, Italy. Tel.: +39 81 7462584; fax: +39 81 7462594. E-mail address: [email protected] (G. Mariniello). 0303-8467/$ – see front matter © 2012 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.clineuro.2012.08.035
Schwannomas of the trigeminal nerve usually present with symptoms of trigeminal impairment, including facial pain or paresthesia, whereas symptoms related to the surrounding nervous structures occur later [1]. No evidence of trigeminal nerve dysfunction is found in about 10% of patients with trigeminal schwannomas, even of large size. It may be assumed that the schwannoma may grow eccentrically, and can leave the trigeminal nerve fibers intact [3], even when the tumor is intimately adherent to the nerve. Diplopia is the most frequent non-trigeminal symptom; it may occur at presentation in about 10% of the patients in association with facial pain and paresthesia [1]. Besides, a deficit of the abducens nerve is found during observation in up to 34% of the patients [1].
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G. Mariniello et al. / Clinical Neurology and Neurosurgery 115 (2013) 1121–1122
Compression and damage of the nerve in trigeminal schwannoma may occur at level of the cavernous sinus (type I schwannomas according to Dolenc) [5] or at the cisternal segment of the nerve itself (type II schwannomas). However, the abducens nerve is a very vulnerable nervous structure. In fact, in the surgical series of trigeminal schwannomas by Goel et al. [1] variable improvement of diplopia was obtained only in 10 among 18 cases (44.4%). An isolated abducens nerve palsy in a patient with MRI finding of a parasellar schwannoma could suggest a schwannoma of the abducens nerve itself. This exceptional tumor may originate from the intracavernous segment of the abducens nerve or from its cisternal part. We think that the correct diagnosis may be doubtful only for intracavernous schwannomas (type I of trigeminal schwannomas according to Dolenc [5]). However in these cases the fronto-temporal epidural approach is similar, and the identification of the involved nerve is established intraoperatively [5]. Stereotactic radiosurgery is a good management option for trigeminal schwannomas as an alternative or adjunct to surgery. It seems ideal for treating small asymptomatic primary, residual or recurrent tumors, mainly if located within the cavernous sinus [1]. 4. Conclusions Although this evidence is exceptional, an isolated abducens nerve palsy should also suggest a trigeminal schwannoma. Surgical excision of the neoplasm may result in remission of the preoperative ocular disturbances. References Fig. 1. Axial (a) and coronal (b) T1-weighted post contrast MRI demonstrate a hyperintense neoplasm arising in the area of the left petrous apex, and extending through the cavernous sinus up to the superior orbital fissure.
Abducens nerve palsy as the unique symptom of trigeminal schwannoma, in absence of trigeminal symptomatology, is an exceptional event, which has been reported in only 2 cases [3,4]. Although an abducens nerve palsy may be observed as a nonlocalizing sign in many intracranial pathologies, its occurrence in cases of trigeminal schwannomas results from a direct compression of the nerve; thus it should be considered a localizing sign.
[1] Goel A, Muzumdar D, Raman C. Trigeminal schwannomas: analysis of surgical experience with 73 cases. Neurosurgery 2003;52:783–90. [2] Mariniello G, Cappabianca P, Buonamassa S, de Divitiis E. Surgical treatment of intracavernous trigeminal schwannomas via a fronto-temporal epidural approach. Clinical Neurology and Neurosurgery 2004;106:104–9. [3] Yamashita J, Asato R, Handa H, Nakao S, Ogata M. Abducens nerve palsy as initial symptom of trigeminal schwannoma. Journal of Neurology, Neurosurgery and Psychiatry 1977;40:1190–7. [4] Del Prior LV, Miller NR. Trigeminal schwannoma as a cause of chronic, isolated sixth nerve palsy. American Journal of Ophthalmology 1989;108:726–9. [5] Dolenc VV. Frontotemporal epidural approach to trigeminal neurinomas. Acta Neurochirurgica 1994;130:55–65.
Contents lists available at SciVerse ScienceDirect
Clinical Neurology and Neurosurgery journal homepage: www.elsevier.com/locate/clineuro
Case report
Abducens nerve palsy as the unique sign of a trigeminal schwannoma Giuseppe Mariniello ∗ , Arcangelo Giamundo, Vincenzo Seneca, Francesco Maiuri Department of Neurosurgery, “Federico II” University School of Medicine, Naples, Italy
a r t i c l e
i n f o
Article history: Received 8 October 2011 Received in revised form 12 August 2012 Accepted 25 August 2012 Available online 30 September 2012 Keywords: Abducens nerve Trigeminal schwannoma Cavernous sinus Skull base tumor
1. Introduction Schwannomas of the trigeminal nerve are benign, uncommon tumors that account for 0.07–0.36% of all intracranial neoplasms and 0.8–8% of intracranial schwannomas [1,2]. They usually present with pain and paresthesia of the face as initial symptoms, whereas disturbances of the extraocular movements are observed later, coupled with trigeminal symptoms, as the result of compression of the abducens or more rarely oculomotor and trochlear nerves [1]. We report an unusual case of a trigeminal schwannoma causing an abducens nerve palsy as unique symptom, and discuss the diagnostic and therapeutic implications of this rare clinical presentation.
During operation the tumor was approached via a frontotemporal epidural approach, as described in a previous report [2]. It allowed to expose extradurally the floor of the middle cranial fossa and the rotundum, ovale and spinosum foramina. The tumor was entirely extradural and originated from the anteromedial portion of the Gasserian ganglion and the second branch of the trigeminal nerve, which were intimately adherent to the tumor. Subtotal tumor resection was achieved using the entry corridors between V1 and V2, and between V2 and V3. The abducens nerve was found to be compressed at level of its precavernous segment. Histologically the tumor was diagnosed as schwannoma. Postoperatively, progressive remission of diplopia occurred within several days. The patient experienced V2 hypaesthesia which disappeared after 1 month.
2. Case report 3. Discussion A 24-year-old woman presented a history of chronic headache. Two months before admission she experienced continuous diplopia in the left gaze. On admission the neurological examination revealed left abducens nerve palsy, whereas the pupils and the eye fundus were normal, and the trigeminal function was preserved along with the pupillar and corneal reflexes. MRI depicted a left parasellar tumor extending from the superior orbital fissure to the apex of the pyramid, with homogeneous contrast enhancement (Fig. 1a and b).
∗ Corresponding author at: Department of Neurosurgery, “Federico II” University School of Medicine, 5 Via S. Pansini, Naples 80131, Italy. Tel.: +39 81 7462584; fax: +39 81 7462594. E-mail address: [email protected] (G. Mariniello). 0303-8467/$ – see front matter © 2012 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.clineuro.2012.08.035
Schwannomas of the trigeminal nerve usually present with symptoms of trigeminal impairment, including facial pain or paresthesia, whereas symptoms related to the surrounding nervous structures occur later [1]. No evidence of trigeminal nerve dysfunction is found in about 10% of patients with trigeminal schwannomas, even of large size. It may be assumed that the schwannoma may grow eccentrically, and can leave the trigeminal nerve fibers intact [3], even when the tumor is intimately adherent to the nerve. Diplopia is the most frequent non-trigeminal symptom; it may occur at presentation in about 10% of the patients in association with facial pain and paresthesia [1]. Besides, a deficit of the abducens nerve is found during observation in up to 34% of the patients [1].
1122
G. Mariniello et al. / Clinical Neurology and Neurosurgery 115 (2013) 1121–1122
Compression and damage of the nerve in trigeminal schwannoma may occur at level of the cavernous sinus (type I schwannomas according to Dolenc) [5] or at the cisternal segment of the nerve itself (type II schwannomas). However, the abducens nerve is a very vulnerable nervous structure. In fact, in the surgical series of trigeminal schwannomas by Goel et al. [1] variable improvement of diplopia was obtained only in 10 among 18 cases (44.4%). An isolated abducens nerve palsy in a patient with MRI finding of a parasellar schwannoma could suggest a schwannoma of the abducens nerve itself. This exceptional tumor may originate from the intracavernous segment of the abducens nerve or from its cisternal part. We think that the correct diagnosis may be doubtful only for intracavernous schwannomas (type I of trigeminal schwannomas according to Dolenc [5]). However in these cases the fronto-temporal epidural approach is similar, and the identification of the involved nerve is established intraoperatively [5]. Stereotactic radiosurgery is a good management option for trigeminal schwannomas as an alternative or adjunct to surgery. It seems ideal for treating small asymptomatic primary, residual or recurrent tumors, mainly if located within the cavernous sinus [1]. 4. Conclusions Although this evidence is exceptional, an isolated abducens nerve palsy should also suggest a trigeminal schwannoma. Surgical excision of the neoplasm may result in remission of the preoperative ocular disturbances. References Fig. 1. Axial (a) and coronal (b) T1-weighted post contrast MRI demonstrate a hyperintense neoplasm arising in the area of the left petrous apex, and extending through the cavernous sinus up to the superior orbital fissure.
Abducens nerve palsy as the unique symptom of trigeminal schwannoma, in absence of trigeminal symptomatology, is an exceptional event, which has been reported in only 2 cases [3,4]. Although an abducens nerve palsy may be observed as a nonlocalizing sign in many intracranial pathologies, its occurrence in cases of trigeminal schwannomas results from a direct compression of the nerve; thus it should be considered a localizing sign.
[1] Goel A, Muzumdar D, Raman C. Trigeminal schwannomas: analysis of surgical experience with 73 cases. Neurosurgery 2003;52:783–90. [2] Mariniello G, Cappabianca P, Buonamassa S, de Divitiis E. Surgical treatment of intracavernous trigeminal schwannomas via a fronto-temporal epidural approach. Clinical Neurology and Neurosurgery 2004;106:104–9. [3] Yamashita J, Asato R, Handa H, Nakao S, Ogata M. Abducens nerve palsy as initial symptom of trigeminal schwannoma. Journal of Neurology, Neurosurgery and Psychiatry 1977;40:1190–7. [4] Del Prior LV, Miller NR. Trigeminal schwannoma as a cause of chronic, isolated sixth nerve palsy. American Journal of Ophthalmology 1989;108:726–9. [5] Dolenc VV. Frontotemporal epidural approach to trigeminal neurinomas. Acta Neurochirurgica 1994;130:55–65.