Clinical commentaryMetastases in cerebellopontine angle from the tumors of central nerve system

- Cerebellopontine angle (CPA) metastasis means malignancy in CPA region due to neuroaxis dissemination.
- The CPA metastases from tumors of central nerve system are very rare.
- CPA metastases can be divided into 2 types including the miliary and massive based on MRI features.
- Therapeutic mainstream requires resection combined with chemo- and/or radio-strategies.
- Prognosis correlates with the primary pathological features.

The objective of this study was to analyze the characters of the cerebellopontine angle (CPA) metastases from central nerve system (CNS) tumors. Ten patients were reviewed for the period between 2008 and 2015. The clinical and neuroimaging features, and treatment outcomes were analyzed retrospectively. The average period during primary diagnosis through the diagnosis of CPA metastases was 42.4 months. Among the 10 cases, the primary tumors and metastases were found simultaneously in 3 cases, the metastases after primary tumor removal were found in 5 cases, and the metastases after stereotaxic radiosurgery were found in 2 cases. Only 4 patients presented with the symptoms and signs associated with CPA involving, one with hearing loss, one presenting facial paralysis, one suffering from tinnitus and one case with dizziness. There were 2 cases with the miliary metastases and 8 cases with massive metastases. There existed 3 cases with single CPA metastases, whereas 7 cases with multiple metastatic foci. Among the 8 cases of massive metastatic foci, 6 tumors presented the solid features and the other 2 cases exhibited cystic and solid features. In this cohort of cases, 4 cases were involved in the bilateral and 6 cases presented unilateral metastatic foci. The three CPA metastases were removed in this group, 6 case performed with radiotherapy, and 5 cases received chemotherapy. In the current group 5 patients have been dead, 3 patients kept stable and 2 cases experienced improvement. In spite of seldom previous reports regarding the metastases from CNS tumors occurring in the CPA are existent, this rare form of the disease should be considered in future evaluation as a differential diagnosis.