Intraductal low papillary histological pattern of carcinoma component shows intraductal spread in invasive carcinoma of the pancreas.

BACKGROUND/PURPOSE: We attempted to discriminate between carcinoma in situ (CIS) and the intraductal invasion/cancerization of invasive ductal carcinoma (IDC) of the pancreas, by comparing the histological patterns of the intraductal components and those of venous invasion.

METHODS

Specimens from 30 patients with IDC were examined histopathologically. Intraductal components and blood vessel invasion in IDC were assessed in specimens stained with hematoxylin & eosin and elastica van Gieson (EVG).

RESULTS

Intraductal components of IDC were found in 28 of the 30 cases of IDC, in 261 ducts, and in 2.3 ducts per one section of one case, on average. The intraductal components of IDC were classified into three histological patterns, as follows: low papillary (including flat), tubular (including solid and cribriform), and mixed (low papillary plus tubular). The incidences of the low papillary, tubular, and mixed patterns in the 261 ducts, were 39% (102 ducts), 56% (145 ducts), and 5% (14 ducts), respectively. The histological pattern of venous invasion was tubular in all but 1 of the 26 cases, and this 1 case showed low papillary patterns as well as a tubular pattern.

CONCLUSIONS

A tubular pattern of intraductal components in IDC of the pancreas indicates intraductal invasion, while a low papillary pattern indicates CIS or carcinoma in another location to which it has spread.