Solitary metastatic breast carcinoma in a trigeminal nerve mimicking a trigeminal neurinoma. Case report.

An unusual case of a metastatic adenocarcinoma located entirely within the trigeminal nerve is reported. The patient, with a history of breast cancer, presented with a pure trigeminal mononeuropathy. The neurological and neuroradiological findings in this patient were quite similar to those of a patient with trigeminal neurinoma. Surgery revealed that the tumor was located within the trigeminal nerve and its appearance was similar to that of a neurinoma. However, histopathological studies proved the tumor to be an adenocarcinoma that was related to the breast cancer treated earlier. A solitary metastatic tumor arising solely in a trigeminal nerve is quite rare; this is the first report of such a case metastasized from breast cancer.