Fluid CEA and CA19-9

Pancreatic cystic lesions include inflammatory pseudocysts, benign serous cystadenomas and mucinous cystic tumours. The mucinous tumours include mucinous cystic neoplasms, which are benign but have the potential for malignant transformation, and mucinous cystadenocarcinoma. Pancreatic cystic lesions may present with recurrent pancreatitis, chronic abdominal pain or jaundice, but in many cases they do not cause any symptoms and are detected by abdomanal ultrasound or other imaging studies undertaken in the evaluation of another disorder. Surgical resection is the treatment for symptomatic patients but could be avoided in asymptomatic patients if it was possible to distinguish between benign and malignant cysts. The clinical and radiological features of these lesions are unreliable to make a pre-operative diagnosis. The concentration of CEA and CA19-9 in aspirated cyst fluid has been suggested as an aid to the differential diagnosis of these lesions. A number of studies have reported fluid CEA values above 350 µg/L in mucinous cysts and below 23 µg/L in benign serous cystadenomas or pseudocysts. The discriminatory power of fluid CA19-9 is less clear which may be due to the association with pancreatitis and the effects of the genetics of the Lewis antigen system on CA19-9 concentrations.