Cystadenocarcinoma versus pseudocyst of the pancreas: a difficult differential diagnosis.

Cystadenocarcinoma of the pancreas is a rare malignant tumor. It may appear as a typical pseudocyst on US and CT. Percutaneous drainage of a presumed pancreatic pseudocyst not only may have complications but also may miss the correct diagnosis. In such patients, only a total excision of the cystic mass and complete pathologic examination can distinguish between inflammatory, benign, or malignant neoplastic lesions.