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cerebellopontine_angle_tumor

Cerebellopontine angle tumor

Epidemiology

Cerebellopontine angle (CPA) lesions account for up to 10% of all intracranial tumors.

Differential diagnosis

Although the preponderance of cerebellopontine angle lesions are schwannomas, focused attention to patient clinical history, imaging studies, and tissue biopsies when indicated will aid in detection of less common lesions that might otherwise be misdiagnosed. This is most critical for pathologies that dictate different management paradigms be undertaken 1).

Types

Clinical features

CPA tumors are estimated to be the secondary cause for up to 9.9% patients with trigeminal neuralgia.

Audiologic evaluation

The most common chief complaint in patients diagnosed with CPA tumors was asymmetrical hearing loss, with most frequent accompanying symptoms being tinnitus in patients with vestibular schwannoma (VS) and dizziness in those with other types of CPA tumor. The most frequent patterns of hearing loss were the descending type in patients with VS and the flat type in patients with non-VS tumors (p < 0.05). Pure tone thresholds tended to increase more in patients with VS than non-VS tumors according to tumor size, and pure tone averages were significantly higher in patients with VS than non-VS tumors of 11-25 mm in size (p < 0.05) 2).

Cerebellopontine angle tumors in infants and children

A plethora of tumor types occur in childhood at the CPA/CMF and a review indicated 50 % were benign in histology. High rates of lower cranial nerve morbidity were experienced but their dysfunctions were often recovered or compensated in 2 years. However, one should be cognizant of these complications and conduct resection with appropriate surgical approach, intraoperative monitoring, and surgical microscope 3).

Treatment

Case series

2016

Twenty-four patients with pathologies at the cerebellopontine lesion were studied. General anesthesia was maintained with fentanyl and propofol. A monopolar stimulator was used at amplitudes of 0.05 to 0.1 mA. Both acoustic and visual signals were displayed as vocalis muscle electromyographic activity using endotracheal tube surface electrodes.

The average number of rootlets was 7.4 (range, 5-10); 75% of patients had 7 or 8 rootlets. As many as 6 rootlets (2-4 in most cases) were responsive in each patient. In 23 of the 24 patients, the responding rootlets congregated on the caudal side. The maximum electromyographic response was predominantly in the most caudal or second most caudal rootlet in 79%.

The majority of motor fibers of the lower cranial nerves run through the caudal part of the rootlets at the cerebellomedullary cistern, and the maximal electromyographic response was elicited at the most caudal or second most caudal rootlet 4).


A study included 171 patients with otologic symptoms who were diagnosed with CPA tumors, including 116 with VS and 55 with other types of CPA tumors. Factors analyzed retrospectively included tumor type, size, and location and the results of audiometric examinations.

The most common chief complaint in patients diagnosed with CPA tumors was asymmetrical hearing loss, with most frequent accompanying symptoms being tinnitus in patients with VS and dizziness in those with other types of CPA tumor. The most frequent patterns of hearing loss were the descending type in patients with VS and the flat type in patients with non-VS tumors (p < 0.05). Pure tone thresholds tended to increase more in patients with VS than non-VS tumors according to tumor size, and pure tone averages were significantly higher in patients with VS than non-VS tumors of 11-25 mm in size (p < 0.05) 5).

1951

ADASAL R, MUTLU N. [Two tumor cases of the pontocerebellar angle with deceiving symptoms]. Concours Med. 1951 Jan 27;73(4):261-5. Undetermined Language. PubMed PMID: 14802047.

1949

BENAIM J. [Tumors of the cerebellopontile angle; considerations on 10 cases]. Neurocirugia. 1949-1950;7:105-28. Undetermined Language. PubMed PMID: 14827057. 6)

1)
Friedmann DR, Grobelny B, Golfinos JG, Roland JT Jr. Nonschwannoma Tumors of the Cerebellopontine Angle. Otolaryngol Clin North Am. 2015 Jun;48(3):461-475. doi: 10.1016/j.otc.2015.02.006. Review. PubMed PMID: 26043142.
2) , 5)
Kim SH, Lee SH, Choi SK, Lim YJ, Na SY, Yeo SG. Audiologic evaluation of vestibular schwannoma and other cerebellopontine angle tumors. Acta Otolaryngol. 2016 Feb;136(2):149-53. doi: 10.3109/00016489.2015.1100326. Epub 2015 Oct 19. PubMed PMID: 26479426.
3)
Tomita T, Grahovac G. Cerebellopontine angle tumors in infants and children. Childs Nerv Syst. 2015 Oct;31(10):1739-50. doi: 10.1007/s00381-015-2747-x. Epub 2015 Sep 9. PubMed PMID: 26351227; PubMed Central PMCID: PMC4564453.
4)
Wanibuchi M, Akiyama Y, Mikami T, Komatsu K, Sugino T, Suzuki K, Kanno A, Ohtaki S, Noshiro S, Mikuni N. Intraoperative Mapping and Monitoring for Rootlets of the Lower Cranial Nerves Related to Vocal Cord Movement. Neurosurgery. 2016 Jun;78(6):829-34. doi: 10.1227/NEU.0000000000001109. PubMed PMID: 26544957.
6)
BENAIM J. [Tumors of the cerebellopontile angle; considerations on 10 cases]. Neurocirugia. 1949-1950;7:105-28. Undetermined Language. PubMed PMID: 14827057.
cerebellopontine_angle_tumor.txt · Last modified: 2018/09/04 13:32 by administrador