Two Cases of Cranial Nerve Metastasis Treated with Radiotherapy and Chemotherapy in Patients with Lung Adenocarcinoma

The incidence of central nervous system metastasis is known to be high among patients with lung cancer. The frequency of brain metastasis and carcinomatous meningitis during the entire clinical course of non-small cell lung cancer is reported to be about 40% and 5%, respectively. In contrast, the incidence of cranial nerve metastasis is extremely rare, and detailed reports of its clinical course remain limited. Herein, we report 2 patients diagnosed with cranial nerve metastasis of lung adenocarcinoma and treated with radiotherapy and systemic chemotherapy. Both patients had cranial nerve symptoms, and brain magnetic resonance imaging showed cranial nerve enhancement. However, no evidence of carcinomatous meningitis was noted on magnetic resonance imaging and cerebrospinal fluid cytology. Based on these observations, these patients were diagnosed with cranial nerve metastasis of lung adenocarcinoma. Radiotherapy and chemotherapy were performed in both cases. In both cases, neurological symptoms had not worsened and imaging findings did not indicate any deteriorations. Therefore, radiotherapy and systemic chemotherapy should be considered when treating cranial nerve metastasis of lung adenocarcinoma. Early therapeutic intervention may lead to attenuation of the cranial nerve dysfunction resulting from cranial nerve metastasis.