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Bilateral cerebellopontine angle and multiple supratentorial masses
Journal of Clinical Neuroscience 13 (2006) 707–708 www.elsevier.com/locate/jocn
Images in neuroscience: Answer
Bilateral cerebellopontine angle and multiple supratentorial masses Kunihiko Kodama, Noojan Kazemi *, Takuya Ishii Department of Neurosurgery, Royal Melbourne Hospital, Parkville, Victoria 3050, Australia Received 5 March 2006; accepted 20 March 2006
Answer B) Neurofibromatosis type 2. Discussion This patient has the hallmark of neurofibromatosis type 2 (NF2)–bilateral vestibular schwannomas (VS) – as well as multiple intracranial meningiomas. At the second operation, two tumours were found adjacent to each other on the left side. The caudal aspect of the left VS was removed followed by complete removal of the adjacent tentorial lesion-a meningioma. Subsequent further removal the left VS was limited by decreased amplitude of the brainstem evoked auditory response (BEAR). Resection was limited due to the need to retain hearing on the sole hearing side. Postoperatively, she recovered well and the left sided hearing was preserved. She had a left facial palsy immediately postoperatively, which improved to normal within one month. Histopathological examination demonstrated a VS on the right (MIB–1 labeling index 6%). On the left, the VS had a MIB–1 labeling index of 10%, which may explain its rapid growth. The other lesion was confirmed to be a meningioma (MIB–1 labeling index 5%). NF2 is an autosomal dominant inherited disorder. The responsible gene is located on chromosome 22q12. The diagnostic criteria for NF2 are:
DOI of question: 10.1016/j.jocn.2006.03.006. Corresponding author. Present address: Department of Epilepsy, Division of Neurosciences, Royal Melbourne Hospital, Parkville, Victoria 3050, Australia. Tel.: +61 3 9342 8408; fax: +61 3 9342 7273. E-mail address: [email protected] (N. Kazemi). *
0967-5868/$ - see front matter Ó 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.jocn.2006.03.007
1. Bilateral VS; or 2. A first-degree relative with NF2, and either a. A unilateral VS or b. Two of the following: meningioma, schwannoma, glioma, posterior subcapsular lens opacity, or cerebral calcification; or 3. Two of following a. A unilateral VS b. Multiple meningiomas c. Either schwannoma, glioma, neurofibroma, posterior subcapsular lens opacity, or cerebral calcification. The prevalence of NF2 is one per 40,000 newborns. Half of these patients have no family history of NF2, and penetrance is almost 100% by 60 years of age.1 In patients with NF2, the clinical course varies considerably from mild (late onset, slow-growing VS) to severe (early onset, multiple, and rapid-growing VS and meningiomas). Multiple tumours may shorten the patient’s life span, but NF2 tumours are also often more aggressive then similar tumours occurring in patients without NF2. Histological comparisons of surgically removed sporadic and NF2 VS demonstrate that NF2 lesions tend to infiltrate the adjacent facial nerve, and have a higher proliferative potential (as was seen in this patient).2,3 It has been speculated that adjacent tumours, as seen in this patient, may promote VS progression by growth factors.4 Of the various options for the management of VS, surgical intervention is generally considered first for NF2 patients, who are often younger in age than those with sporadic VS. Total removal of the tumour is the aim, however partial removal may be acceptable if hearing preservation is a priority. Treatment of the lesion on the side of sole useful hearing remains controversial. For a large compressive VS, surgery may be the only reasonable option. Hearing preservation is achieved in 68% of NF2 patients after
708
Images in neuroscience / Journal of Clinical Neuroscience 13 (2006) 707–708
surgery for VS diameter less than 2.5 cm after surgery, which is similar to sporadic VS.5 Whilst, stereotactic radiosurgery has emerged as a treatment option for smaller VS, it is associated with treatment failure in 62% of tumours with a diameter more than 3 cm and 6% with diameter less than 3 cm.6 In recent reports, hearing is preserved in approximately 40 to 70% of patients following reduced-dose radiosurgery.7,8 Stereotactic radiosurgery thus seems attractive for the VS less than 3 cm in diameter but hearing preservation is not better than with surgery. If radiosurgery fails, subsequent surgical removal has been reported to be technically more difficult due to the development of fibrous tissue and adhesions around the cranial nerves, tumour and surrounding structures.9 Thus, hearing preservation is technically more difficult at surgery after previous radiosurgery. There is also concern for a small but significant potential for malignant transformation in VS and induction of other tumours, particularly sarcomas and meningiomas, within the radiation fields. In NF2, the development of a permanent and irreversible hearing loss is unpredictable and can be sudden,10 and therefore the timing of intervention is extremely important to maximize hearing preservation. Follow-up imaging at 6 monthly intervals has previously been recommended,11 but as this case demonstrates, deficits may develop quickly and tumours enlarge rapidly, and thus more frequent imaging may be important. Acknowledgement We thank Dr Alpha Tsui, Dr Vanessa Fahey and Professor Michael Gonzales for histopathological diagnosis. We thank Mr Robert JS Briggs and Professor Andrew H Kaye for advice and allowing us to report their patient.
References 1. Louis DN, Stermmer-Rachamimov AO, Wiestler OD. Neurofibromatosis type 2. In: Kleihues P, Cavenee WK, editors. Pathology & Genetics of Tumours of the Central Nervous System. World Health Organization Classification of Tumours. Lyon: IARC Press; 2000. p. 219–22. 2. Aguiar PH, Tatagiba M, Samii M, et al. The comparison between the growth fraction of bilateral vestibular schwannomas in neurofibromatosis 2 (NF2) and unilateral vestibular schwannomas using the monoclonal antibody MIB 1. Acta Neurochir (Wien) 1995;134:40–5. 3. Antinheimo J, Haapasalo H, Seppa¨la¨ M, et al. Proliferative potential of sporadic and neurofibromatosis 2-associated schwannomas as studied by MIB–1 (Ki–67) and PCNA labeling. J Neuropathol Exp Neurol 1995;54:776–82. 4. Pallini R, Tancredi A, Casalbore P, et al. Neurofibromatosis type 2: growth stimulation of mixed acoustic schwannoma by concurrent adjacent meningioma: possible role of growth factors. J Neurosurg 1998;89:149–54. 5. Slattery III WH, Brackmann DE, Hitselberger W. Hearing preservation in neurofibromatosis type 2. Am J Otol 1998;19: 638–43. 6. Hasegawa T, Kida Y, Kobayashi T, et al. Long-term outcomes in patients with vestibular schwannomas treated using gamma knife surgery: 10-year follow up. J Neurosurg 2005;102:10–6. 7. Flickinger JC, Kondziolka D, Niranjan A, et al. Results of acoustic neuroma radiosurgery: an analysis of 5 years’ experience using current methods. J Neurosurg 2001;94:1–6. 8. Iwai Y, Yamanaka K, Shiotani M, et al. Radiosurgery for acoustic neuromas: results of low-dose treatment. Neurosurgery 2003;53: 282–8. 9. Schulder M, Sreepada GS, Kwartler JA, et al. Microsurgical removal of a vestibular schwannoma after stereotactic radiosurgery: Surgical and Pathologic Findings. Am J Otol 1999;20:364–8. 10. Driscoll CL, Jackler RK, Pitts LH, et al. Lesions of the internal auditory canal and cerebellopontine angle in an only hearing ear: is surgery ever advisable? Am J Otol 2000;21:573–81. 11. Briggs RJ, Fabinyi G, Kaye AH. Current management of acoustic neuromas: review of surgical approaches and outcomes. J Clin Neurosci 2000;7:521–6.
Images in neuroscience: Answer
Bilateral cerebellopontine angle and multiple supratentorial masses Kunihiko Kodama, Noojan Kazemi *, Takuya Ishii Department of Neurosurgery, Royal Melbourne Hospital, Parkville, Victoria 3050, Australia Received 5 March 2006; accepted 20 March 2006
Answer B) Neurofibromatosis type 2. Discussion This patient has the hallmark of neurofibromatosis type 2 (NF2)–bilateral vestibular schwannomas (VS) – as well as multiple intracranial meningiomas. At the second operation, two tumours were found adjacent to each other on the left side. The caudal aspect of the left VS was removed followed by complete removal of the adjacent tentorial lesion-a meningioma. Subsequent further removal the left VS was limited by decreased amplitude of the brainstem evoked auditory response (BEAR). Resection was limited due to the need to retain hearing on the sole hearing side. Postoperatively, she recovered well and the left sided hearing was preserved. She had a left facial palsy immediately postoperatively, which improved to normal within one month. Histopathological examination demonstrated a VS on the right (MIB–1 labeling index 6%). On the left, the VS had a MIB–1 labeling index of 10%, which may explain its rapid growth. The other lesion was confirmed to be a meningioma (MIB–1 labeling index 5%). NF2 is an autosomal dominant inherited disorder. The responsible gene is located on chromosome 22q12. The diagnostic criteria for NF2 are:
DOI of question: 10.1016/j.jocn.2006.03.006. Corresponding author. Present address: Department of Epilepsy, Division of Neurosciences, Royal Melbourne Hospital, Parkville, Victoria 3050, Australia. Tel.: +61 3 9342 8408; fax: +61 3 9342 7273. E-mail address: [email protected] (N. Kazemi). *
0967-5868/$ - see front matter Ó 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.jocn.2006.03.007
1. Bilateral VS; or 2. A first-degree relative with NF2, and either a. A unilateral VS or b. Two of the following: meningioma, schwannoma, glioma, posterior subcapsular lens opacity, or cerebral calcification; or 3. Two of following a. A unilateral VS b. Multiple meningiomas c. Either schwannoma, glioma, neurofibroma, posterior subcapsular lens opacity, or cerebral calcification. The prevalence of NF2 is one per 40,000 newborns. Half of these patients have no family history of NF2, and penetrance is almost 100% by 60 years of age.1 In patients with NF2, the clinical course varies considerably from mild (late onset, slow-growing VS) to severe (early onset, multiple, and rapid-growing VS and meningiomas). Multiple tumours may shorten the patient’s life span, but NF2 tumours are also often more aggressive then similar tumours occurring in patients without NF2. Histological comparisons of surgically removed sporadic and NF2 VS demonstrate that NF2 lesions tend to infiltrate the adjacent facial nerve, and have a higher proliferative potential (as was seen in this patient).2,3 It has been speculated that adjacent tumours, as seen in this patient, may promote VS progression by growth factors.4 Of the various options for the management of VS, surgical intervention is generally considered first for NF2 patients, who are often younger in age than those with sporadic VS. Total removal of the tumour is the aim, however partial removal may be acceptable if hearing preservation is a priority. Treatment of the lesion on the side of sole useful hearing remains controversial. For a large compressive VS, surgery may be the only reasonable option. Hearing preservation is achieved in 68% of NF2 patients after
708
Images in neuroscience / Journal of Clinical Neuroscience 13 (2006) 707–708
surgery for VS diameter less than 2.5 cm after surgery, which is similar to sporadic VS.5 Whilst, stereotactic radiosurgery has emerged as a treatment option for smaller VS, it is associated with treatment failure in 62% of tumours with a diameter more than 3 cm and 6% with diameter less than 3 cm.6 In recent reports, hearing is preserved in approximately 40 to 70% of patients following reduced-dose radiosurgery.7,8 Stereotactic radiosurgery thus seems attractive for the VS less than 3 cm in diameter but hearing preservation is not better than with surgery. If radiosurgery fails, subsequent surgical removal has been reported to be technically more difficult due to the development of fibrous tissue and adhesions around the cranial nerves, tumour and surrounding structures.9 Thus, hearing preservation is technically more difficult at surgery after previous radiosurgery. There is also concern for a small but significant potential for malignant transformation in VS and induction of other tumours, particularly sarcomas and meningiomas, within the radiation fields. In NF2, the development of a permanent and irreversible hearing loss is unpredictable and can be sudden,10 and therefore the timing of intervention is extremely important to maximize hearing preservation. Follow-up imaging at 6 monthly intervals has previously been recommended,11 but as this case demonstrates, deficits may develop quickly and tumours enlarge rapidly, and thus more frequent imaging may be important. Acknowledgement We thank Dr Alpha Tsui, Dr Vanessa Fahey and Professor Michael Gonzales for histopathological diagnosis. We thank Mr Robert JS Briggs and Professor Andrew H Kaye for advice and allowing us to report their patient.
References 1. Louis DN, Stermmer-Rachamimov AO, Wiestler OD. Neurofibromatosis type 2. In: Kleihues P, Cavenee WK, editors. Pathology & Genetics of Tumours of the Central Nervous System. World Health Organization Classification of Tumours. Lyon: IARC Press; 2000. p. 219–22. 2. Aguiar PH, Tatagiba M, Samii M, et al. The comparison between the growth fraction of bilateral vestibular schwannomas in neurofibromatosis 2 (NF2) and unilateral vestibular schwannomas using the monoclonal antibody MIB 1. Acta Neurochir (Wien) 1995;134:40–5. 3. Antinheimo J, Haapasalo H, Seppa¨la¨ M, et al. Proliferative potential of sporadic and neurofibromatosis 2-associated schwannomas as studied by MIB–1 (Ki–67) and PCNA labeling. J Neuropathol Exp Neurol 1995;54:776–82. 4. Pallini R, Tancredi A, Casalbore P, et al. Neurofibromatosis type 2: growth stimulation of mixed acoustic schwannoma by concurrent adjacent meningioma: possible role of growth factors. J Neurosurg 1998;89:149–54. 5. Slattery III WH, Brackmann DE, Hitselberger W. Hearing preservation in neurofibromatosis type 2. Am J Otol 1998;19: 638–43. 6. Hasegawa T, Kida Y, Kobayashi T, et al. Long-term outcomes in patients with vestibular schwannomas treated using gamma knife surgery: 10-year follow up. J Neurosurg 2005;102:10–6. 7. Flickinger JC, Kondziolka D, Niranjan A, et al. Results of acoustic neuroma radiosurgery: an analysis of 5 years’ experience using current methods. J Neurosurg 2001;94:1–6. 8. Iwai Y, Yamanaka K, Shiotani M, et al. Radiosurgery for acoustic neuromas: results of low-dose treatment. Neurosurgery 2003;53: 282–8. 9. Schulder M, Sreepada GS, Kwartler JA, et al. Microsurgical removal of a vestibular schwannoma after stereotactic radiosurgery: Surgical and Pathologic Findings. Am J Otol 1999;20:364–8. 10. Driscoll CL, Jackler RK, Pitts LH, et al. Lesions of the internal auditory canal and cerebellopontine angle in an only hearing ear: is surgery ever advisable? Am J Otol 2000;21:573–81. 11. Briggs RJ, Fabinyi G, Kaye AH. Current management of acoustic neuromas: review of surgical approaches and outcomes. J Clin Neurosci 2000;7:521–6.