Analysis of isolated cranial nerve manifestations in patients with cancer.

The aim of this study was to assess the underlying causes of isolated cranial nerve (CN) manifestations in cancer patients. In a prospective study over a 16 month period, 20 of 242 patients presented with isolated CN manifestations, and were assessed for the following: primary site; CN symptoms and signs; length of time between primary diagnosis and neurological involvement; and survival following the neurological diagnosis. The most frequent primary site was determined as hematological malignancy (9/20). Thirteen of the 20 patients presented with single CN manifestations. Underlying causes of CN manifestations in 16 of the 20 patients were related to metastases. They included meningeal carcinomatosis (10/16), brain stem metastases (3/16), primary brain astrocytomas (1/16), and metastases out of the central nervous system (2/16). The remaining four patients' CN manifestations related to non-metastatic conditions. Although most of the isolated CN manifestations were due to systemic metastasis, in particular to the meninges, up to 20% were related to benign conditions.