Abstract
Background. We herein report a case of lung adenocarcinoma with gefitinib-resistant carcinomatous meningitis exhibiting dose-dependent effects of erlotinib. Case. A 68-year-old non-smoking female was diagnosed with lung adenocarcinoma, cT1bN3M1b, cStage IV and found to be positive for an epidermal growth factor receptor gene mutation (Exon 21: L858R). She was treated with gefitinib and achieved a partial response (PR). Although the CEA level gradually became elevated after 10 months of treatment, we continued the gefitinib therapy because no lesions were classified as demonstrating progressive disease (PD). The patient was subsequently admitted to our hospital due to vomiting and anorexia. The spinal fluid displayed an increased protein level and decreased glucose level, whereas no CEA elevation or atypical cells were observed. Brain MRI showed findings indicative of brain metastasis, with meningeal dissemination in the basal ganglia. Therefore, we comprehensively diagnosed the patient with carcinomatous meningitis and changed the treatment regimen from 250 mg of daily gefitinib to 150 mg of daily erlotinib. Within one week, her symptoms improved and the CEA level declined. However, we again decreased the daily dose of erlotinib from 150 mg to 100 mg due to a severe rash. Unfortunately, her headache worsened and the CEA level again became elevated; therefore, we increased the dose to 125 mg and 150 mg, after which the patient's symptoms improved and the CEA level decreased. Conclusions. This case suggests that adequate treatment with erlotinib improves carcinomatous meningitis in patients resistant to gefitinib.
