[Lung carcinoma producing carbohydrate antigen 19-9; report of a case]

A 58-year-old female was admitted to our hospital for investigation of serum elevation of carbohydrate antigen (CA 19-9). Computed tomography of the chest revealed a spiculated pulmonary nodule with the longest diameter of 3.7 cm in the right lower lobe. The diagnosis of lung adenocarcinoma was made. The patient underwent right lower lobectomy with lymphnode dissection. Histological examination revealed acinar type adenocarcinoma. The tumor was classified as stage IB with T2aN0M0. Immunohistochemically, the tumor cells stained positively for CA19-9. The serum CA19-9 level returned to a normal level after operation, but increased again with mediastinal lymphnode metastasis and brain metastasis. She died after an operation in 16 months.