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Bilateral acoustic neurinomas presenting as subarachnoid hemorrhage: case report

CHU, Ming; WEI, Lan-lan; LI, Guo-zhong; LIN, You-zhi; ZHAO, Shi-guang

Case report
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SDC

Department of Neurosurgery (Chu M, Li GZ, Lin YZ and Zhao SG), Department of Microbiology (Wei LL), First Affiliated Hospital of Harbin Medical University, Harbin 150001, China

Correspondence to: Dr. CHU Ming, Department of Neurosurgery, First Affiliated Hospital of Harbin Medical University, Harbin 150001, China (Tel: 86–451–53643849 ext 5098 or 86–451–89695527. Email: chuming120@sohu.com)

This study was supported by a grant from the National Natural Science Foundation of China (No. 30600204).

(Received February 17, 2006)

Edited by LUO Dan

Acoustic neurinoma usually results in impairment of facial nerve and hearing, and rarely leads to subarachnoid hemorrhage (SAH). In 2002, we treated a patient with bilateral acoustic neurinomas presenting as SAH.

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CASE REPORT

A 45-year-old women complaining of left-sided tinnitus for three months and a sudden onset of severe headache in the left posterior auricular region followed by nausea, vomiting and left facial numbness, was admitted to our hospital on April 28, 2002. Neurological examination on admission showed slight hearing loss on the left side and a stiff neck. Systemic blood pressure was normal. CT scanning revealed an isodense mass in the right cerebellopontine angle (CPA) and a nearly round high-density area in the left CPA (Fig. 1). The T1- and T2-weighted MRI showed slightly hypointense masses and hyperintense masses respectively in the both CPAs (Fig. 2). A contrast-enhanced T1-weighted MRI demonstrated that both the masses can be enhanced with cystic components in the left mass (Fig. 3). Brainstem auditory evoked responses (BAER) test revealed a delay of wave III-V interval in the left ear. Erythroic cerebrospinal fluid with a high opening pressure of 260 mmH2O was collected from a lumbar puncture. The patient was diagnosed with SAH.

Fig. 1.

Fig. 1.

Fig. 2.

Fig. 2.

Fig. 3.

Fig. 3.

Ten days after admission, bilateral suboccipital craniectomy was carried out. After the arachnoid membrane, which was slightly thick and turbid, was incised near the cisterna magna, the two tumors in the both CPAs were exposed. The tumors were covered with a yellowish brown capsule, which looked like an old hematoma membrane, suggesting an old intratumoral hemorrhage. During the operation, the fluid within the cyst was confirmed to be xanthochromic. The two tumors were thoroughly extirpated without injuring the facial nerve. Histological examination showed mixed neurinomas of types A and B with several hypervascular areas characterized by numerous dilated thin-walled vessels (Fig. 4). Two weeks after the operation, MRI scan confirmed that the tumors had disappeared completely (Fig. 5). Three years later, the patient returned to fulltime work only with a slight hearing loss on the left ear.

Fig. 4.

Fig. 4.

Fig. 5.

Fig. 5.

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DISCUSSION

Hemorrhage from brain tumors accounts for 1%-11% of intracranial bleeding,1 1%-2% of the hemorrhage occurred beneath the arachnoid including three types: SAH, intratumoral hemorrhage with SAH, and intracerebral hematoma surrounding the brain tumor with SAH.2 SAH usually results from a brain or spinal cord tumor. Only a few cases of acoustic neurinomas presenting as SAH were reported,1–8 the first one was described by McCoyd and colleagues in 1974.3 In all of these cases, however, no acoustic neurinoma occurred bilaterally.

Bilateral acoustic neurinoma is also known as neurofibromatosis type 2 (NF2), which is characterized by multiple tumors on the cranial and spinal nerves affecting both of the auditory nerves, and other lesions of the brain and spinal cord, occurring in 1/40 000 births.We had found only one record of spinal subarachnoid hematoma located around the cauda equina associated with NF2, but the spinal subarachnoid hematoma might have been caused by spontaneous bleeding from multiple small tumors associated with NF2.9 Our report of bilateral acoustic neurinoma presenting as SAH is extremely rare.

The mechanisms of hemorrhage from an acoustic neurinoma are not clarified yet. Tumors larger than 2 cm in diameter, with mixed Antoni types and dilated thin-walled vessels,7,8 combined with a ruptured aneurysm,2 or rapid growth,10 are apt to hemorrhage. In our case, no gross hemorrhage was visible; hemosiderin was presented in both macrophages and in tumoral tissues under a microscope. Cystic formations were also found, which probably resulted from intratumoral bleeding. Histological examination showed a mixture of Antoni types A and B. There were several hypervascular areas characterized by numerous dilated thin-walled vessels in the tumor. The tumoral vessels are often composed of endothelial wall, showing intense proliferative areas through which hemorrhage occur easily.

Early surgical intervention is feasible for acoustic tumors in patients with NF2, with high rates of hearing and facial nerve function preservation.11 We removed the two tumors totally through bilateral suboccipital craniotomies. During a 3-year follow-up, the patient has “serviceable” hearing and normal facial nerve function.

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REFERENCES

1. Yonemitsu T, Niizuma H, Kodama N, Fujiwara S, Suzuki J. Acoustic neurinoma presenting as subarachnoid hemorrhage. Surg Neurol 1983; 20: 125-130.
2. Kodama T, Matsukado Y, Takamoto K. Acoustic schwannoma presenting as subarachnoid hemorrhage due to ruptured contact aneurysm. Surg Neurol 1987; 27: 77-80.
3. McCoyd K, Barron KD, Cassidy RJ. Acoustic neurinoma presenting as subarachnoid hemorrhage. Case report. J Neurosurg 1974; 41: 391-393.
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7. Arienta C, Caroli M, Crotti FM. Subarachnoid hemorrhage due to acoustic neurinoma. Case report and review of the literature. Neurochirurgia (Stuttg) 1988; 31: 162-165.
8. Misra BK, Rout D, Bhiladvala DB, Radhakrishnan V. Spontaneous haemorrhage in acoustic neurinomas. Br J Neurosurg 1995; 9: 219-221.
9. Inoue T, Miyamoto K, Kushima Y, Kodama H, Nishibori H, Hosoe H, et al. Spinal subarachnoid hematoma compressing the conus medullaris and associated with neurofibromatosis type 2. Spinal Cord 2003; 41: 649-652
10. Ohta S, Yokoyama T, Nishizawa S. Massive hemorrhage into acoustic neurinoma related to rapid growth of the tumour. Br J Neurosurg 1998; 12: 455- 457.
11. Brackmann DE, Fayad JN, Slattery WH 3rd, Friedman RA, Day JD, Hitselberger WE et al. Early proactive management of vestibular schwannomas in neurofibromatosis type 2. Neurosurgery 2001; 49: 274-280.
Keywords:

bilateral acoustic neurinoma; subarachnoid hemorrhage

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