Intraductal papillary mucinous tumor of the pancreas is characterized by intraductal papillary proliferation of mucin-producing epithelial cells with or without excessive mucin secretion. According to the degree of epithelial dysplasia, intraductal papillary mucinous tumor is classified into adenoma, borderline tumor, and carcinoma. We recently experienced a case of fine needle aspiration cytology of the intraductal papillary mucinous adenoma in a 69-year-old male. The fine needle aspiration cytology yielded flat sheets of columnar, mucin containing epithelial cells in the background of dense mucin containing degenerated cellular material and histiocytes.
BACKGROUND Usually, a malignant intraductal papillary mucinous tumor (IPMT) of the pancreas shows invasive carcinoma. Recently, IPMT with an unusual growth pattern of a fistulous extension was reported. However, little is known about malignant IPMTs with a different growth pattern of invasion and fistulous extension. METHODS Malignant IPMTs were classified into invasive (colloid or tubular type) carcinomas and the fistulous extension type according to their growth patterns. Their clinicopathological characteristics were compared. RESULTS Among a total of 68 cases of IPMT, there were 16 cases with malignant IPMT; eight, six and two of the colloid, tubular, and fistulous extension types, respectively. The immunohistochemical (IHC) expression of MUC1 was found in seven out of eight colloid and five out of six tubular types, but there was no IHC expression of MUC1 in the fistulous extension type. The IHC expression of MUC2 was noted in one of the eight colloid, one of the six tubular and in both cases with the fistulous extension type.
There was no difference in the tumor recurrence rates bet- ween the different growth patterns. CONCLUSIONS IPMT with the fistulous extension type has a peculiar extension pattern consisting of multiple fistulous tracts without a mass. Although most of the epithelium in the fistulous tract show moderate to severe dysplasia, only the fistulous extension should be considered to be an unusual growth pattern of malignant IPMT. The clinical significance of this unusual type of IPMT remains to be determined.
Jin Hee Sohn, Kyung Me Kim, Seoung Wan Chae, Woo Ho Kim, Woo Sung Moon, Young Nyun Park, Chul Gun Park, Eun sil Yu, Hee Kyung Jang, Hee Jin Jang, Jong Jae Jung, Jin Sook Jung, So Young Jin, Jong Sang Choi, Dae Young Kang
BACKGROUND Mucin producing cystic neoplasms, such as mucinous cystic tumor (MCT) and intraductal papillary mucinous tumor (IPMT) of the pancreas, are uncommon but become increasing in their incidences. The pathologic classification and biologic potential of these neoplasmsremain the subject of controversy. METHODS The Gastrointestinal Pathology Study Group of the Korean Society of Pathologists analyzed the clinicopathologic characteristics of 85 casesof MCT and 72 cases of IPMT and examined the expression patterns of p53, CEA and MUC1. RESULTS IPMT was located largely in the head, and showed connection with the main pancreatic duct (MPD, 68.1%), no ovarian-like stroma (0/72), and presence of intervening intratumoralnormal or atrophic parenchyma. On the other hand, MCT was located largely in thetail (73%), and showed common ovarian-like stroma (66/80), rare connection with the MPD(7/85) and no intervening pancreatic parenchyma. CEA and p53 immunoexpressions weresignificantly increased from adenoma through borderline to carcinoma, but MUC 1 was expressedonly in the invasive carcinoma among cases of MCT and IPMT. CONCLUSIONS The tumorlocation, ovarian-like stroma, connection with the MPD and intratumoral intervening nonneoplastictissue were helpful in the differential diagnosis between IPMT and MCT. CEA and p53expressions can be indicators of malignancy, while MUC 1 expression can indicate invasion.