Small intraductal papillary-mucinous adenomas of the pancreas

Intraductal papillary-mucinous tumors in the pancreas have recently been described as a distinct entity, but the classification of these neoplasms remains under debate. Of issue is the biologic potential of these lesions and the predictability of clinical behavior on the basis of histologic appearance. We report two cases with intraductal papillary tumors formed by highly differentiated mucin-containing columnar epithelium found incidentally at autopsy. Both were classified as adenomas on the basis of histologic features. Neither patient experienced symptoms from their lesion during life and both died of other causes. Both lesions were studied by the polymerase chain reaction and were found to harbor codon 12 mutations in the c-K-ras gene. The concept that these neoplasms represent an early stage in an adenoma-carcinoma sequence is discussed.