Successful re-treatment with gefitinib for carcinomatous meningitis as disease recurrence of non-small-cell lung cancer

We report the case of a woman with gefitinib-sensitive lung adenocarcinoma, who was successfully re-treated with gefitinib for carcinomatous meningitis as the disease recurrence. The good response to gefitinib treatment was supported in part by the existence of epidermal growth factor receptor mutation in carcinoma cells in the specimen obtained from transbronchial lung biopsy, in which E709G in exon 18 and L858R in exon 21 were shown. Although carcinomatous meningitis had been well controlled by the treatment with gefitinib, serum carcinoembryonic antigen (CEA) level increased with re-growth of primary tumor and development of lymphangitic carcinomatosis. Immunohistochemical findings revealed de novo emergence of CEA-producing carcinoma cells in the biopsy specimen taken after recurrence of pulmonary lesion during re-treatment of gefitinib, but revealed little or no CEA expression in the specimen obtained at first presentation. These facts may suggest the possibility of oligo clonality of carcinoma cells in this case.