Mucinous cystadenoma is a type of cystic neoplasm. This type of tumor is usually benign when small but can grow and degenerate into a frank cancer. Most patients with these tumors are in their 5th and 6th decade and it is more common in women. Most of these tumors occur in the body and tail of the pancreas. As with serous cystadenomas they can usually be definitely diagnosed with modern diagnostic testing. When small (<3cm) and asymptomatic, most experts feel these lesions can be safely observed provided there is close surveillance with CT scans. If the lesion is >3cm, causing symptoms or obstructing the pancreatic duct they should be surgically excised. Even if a cystadenocarcinoma is found, the prognosis is quite good if the tumor can be surgically removed.