Two cases of pancreatic cystadenocarcinoma with elevated CA 19-9 levels in the cystic fluid in comparison with two cases of pancreatic cystadenoma.

A 39-year-old woman was hospitalized with left hypochondralgia. Ultrasonography and abdominal computed tomography showed a cystic mass in the tail of the pancreas. Echo-guided aspiration of the cyst was performed, and a markedly elevated CA 19-9 level in the cystic fluid was found. A surgical operation was performed, and the tumor was radically resected. The pathologic diagnosis was papillary adenocarcinoma of the pancreas. Another case of pancreatic cystadenocarcinoma also had an extremely high cystic CA 19-9 level, whereas two cases with benign pancreatic cysts had very low cystic CA 19-9 levels. Moreover, positive localization of CA 19-9 in the cancerous tissue was clearly demonstrated by an immunohistochemical technique, indicating active secretion of CA 19-9 into the cyst, while CA 19-9 in the tissue of pancreatic cystadenoma was almost non-existent. Measurement of the CA 19-9 level in the cystic fluid might therefore be a valuable additional aid in the diagnosis of cystadenocarcinoma of the pancreas.