Cystic schwannomas of the jugular foramen: Clinical and surgical remarks

OBJECTIVE: The goals of this report were to outline the clinical presentati on, radiological characteristics, surgical techniques, postoperative morbid ity, and long-term follow-up results for cystic jugular foramen (JF) schwan nomas and to describe their differences, compared with solid schwannomas in volving the JF. METHODS: A retrospective analysis of radiological studies and surgical reco rds identified five primarily cystic tumors among 21 cases of JF schwannoma s that had been surgically treated at our institution. RESULTS: Two types of cystic JF schwannomas were observed, i.e., Type 1 les ions, which are single large cysts with thin ring-like enhancement of the t umor wall, and Type 2 lesions, which are multiple cysts with very irregular , thick enhancement of the cyst wall. The most common symptoms were hearing loss, ataxia, and headaches. Total surgical removal could be performed in all cases. The immediate postoperative findings indicated hearing improveme nt in three cases. No deterioration of lower cranial nerve function was obs erved. All patients were independent in the immediate postoperative period and in the long-term follow-up period (Karnofsky Performance Scale score, 9 0). CONCLUSION: Surgical treatment of cystic JF schwannomas can be very demandi ng because of generally stronger adhesion of the tumor capsule to the surro unding structures, fragile tumor capsules, and difficulty in identification of the arachnoidal planes in some cases. Early identification of the arach noidal planes without opening of the cyst and sharp dissection may be usefu l. Careful intradural opening of the JF should be performed to achieve tota l removal of the last tumor portion within the JF. A comparison of these le sions with solid schwannomas involving the JF indicated that cystic tumors affected a younger population, with less preoperative swallowing impairment (P < 0.05). The immediate postoperative course in both types of cystic JF schwannomas was usually better than for solid lesions, because of minor pos toperative cranial nerve morbidity, especially involving lower cranial nerv e function, in the latter cases. Long-term follow-up data failed to demonst rate any significant differences in final patient outcomes, however.