Clinicopathologic view of intraductal papillary-mucinous tumor of the pancreas.

Intraductal papillary-mucinous tumors (IPMTs) of the pancreas form a special group of neoplasms characterized by intraductal papillary growth of mucin-producing columnar cells. Included among these neoplasms are papillary and villous adenomas, lesions with mucinous duct ectasia and mucin-producing carcinomas. Most patients are males and present with episodic pancreatitis-like symptoms, which may have been noted for years. These symptoms are due to incomplete and later complete duct obstruction by papillary proliferations and/or mucin, which eventually cause fibrotic atrophy of the normal parenchyma. At the time of diagnosis, malignant non-invasive IPMTs are observed in 5-30% of the cases. Fifteen to forty percent of the IPMTs show invasion and half of the invasive IPMTs have metastases. Pre-operatively, invasiveness cannot be predicted. Patients with non-invasive IPMT survive for long periods after surgery, as do many patients with invasive, non-metastatic IPMT, although intraductal proliferation with a mild degree of atypia may be present at the resection margin. In patients with invasive and metastatic IPMT, survival ranges from a few months up to 3 years.