Cerebrospinal fluid cytology to aid the diagnosis of cerebellopontine angle tumors.

OBJECTIVE: To determine if cerebrospinal fluid (CSF) cytology can be useful in the workup of patients with internal auditory canal/cerebellopontine angle (IAC/CPA) tumors and facial paralysis to diagnose metastatic disease before surgical intervention. STUDY DESIGN: Retrospective case series. SETTING: Tertiary referral center. PATIENTS: Patients who presented with or developed facial paralysis and IAC/CPA tumors. OUTCOME MEASURE: Lumbar puncture and CSF cytological analysis. RESULTS: Seven patients presented with or developed high-grade facial paralysis (greater than House-Brackmann Grade II). In the first patient, excision of the tumor revealed adenocarcinoma. All subsequent patients were evaluated with CSF cytological analysis. In five of these patients, cytological CSF analysis revealed malignant cells, suggesting a diagnosis of a metastatic lesion rather than acoustic neuroma. Primary neoplasms were identified in all but one of these patients. A sixth patient had metastatic breast cancer, but negative CSF cytology and a stable CPA tumor after radiation treatment. Two patients who were being conservatively followed up for their IAC/CPA tumor developed a nonprogressive but persistent mild Grade II facial weakness and underwent CSF analysis which tested negative. One patient had surgical resection with pathologic findings consistent with a typical acoustic schwannoma, and the other patient has been conservatively followed up without change. CONCLUSION: Our experience suggests that patients presenting with IAC/CPA tumors and progressive facial paralysis of House-Brackmann Grade III or greater should have a CSF cytological examination before surgical intervention to evaluate for a malignant process.