Small-cell Lung Cancer and Elevated CA 19.9 Tumor Marker Levels Carcinoma microcítico de pulmón y elevación del marcador

The CA 19.9 antigen is a glycoprotein synthesized in several epithelia that is typically high in the serum of patients with pancreatic tumors. Thus, levels above 300 U/l have a positive predictive value of about 90%.1 Other tumors (bile duct, gastric, colon, hepatic, ovarian, endometrial, pulmonary, or urothelial) or different benign processes (hepatitis, cirrhosis, cholangitis, cholecystitis, pancreatic pseudocyst, pancreatitis, pulmonary fibrosis, bronchial asthma, asbestosis, bronchiectasis, tuberculosis, renal failure, mucinous cysts, hydronephrosis, Sjögren’s syndrome, rheumatoid arthritis, erythematous lupus, dermatopolymyositis, or giant cell arteritis2–4) may also run their course with high serum CA 19.9 levels (in the latter case, with more moderate values). Increased serum levels of CA 19.9 in lung tumors, especially in adenocarcinomas, are a known fact, although uncommon.5–7 Therefore, we consider it interesting to discuss 4 cases of pulmonary non-small-cell carcinoma treated in our unit within the last 2 years. The notably high CA 19.9, especially in 2 of the patients,