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

Pathological survey of precursor lesions in cholangiocarcinoma

BACKGROUND

To clarify the pathological significance of two precursors (high-grade biliary intraepithelial neoplasm [BilIN] and intraductal papillary neoplasm of bile duct [IPNB]) in cholangiocarcinomas (CCAs).

METHODS

Ninety-one cases of CCA (47 distal CCAs [dCCAs], 31 perihilar CCAs [pCCAs] and 13 intrahepatic CCAs of large duct type [LD-iCCAs]) were examined for their association with precursors. Neoplastic intraepithelial lesions without underlying infiltrating carcinoma in the surrounding mucosa of CCAs were considered to reflect high-grade BilIN. High-grade BilIN and IPNB were subdivided into gastric, biliary, intestinal and oncocytic subtypes, while CCAs were subdivided into gastrobiliary, intestinal and oncocytic subtypes. The postoperative overall survival (OS) was examined.

RESULTS

Fifty-four and 8 of 91 CCAs were associated with high-grade BilIN and IPNB, respectively, while these precursors were unidentifiable in the remaining CCAs. A majority of CCAs were of the gastrobiliary subtype, while the intestinal subtype was occasionally detected, and the oncocytic subtype was rare. CCAs with high-grade BilIN showed a similar postoperative OS to CCAs without precursors, while CCAs with IPNB showed a favorable postoperative OS compared to CCAs without precursors.

CONCLUSIONS

CCAs were frequently associated with precursors; high-grade BilIN may be a major precursor and IPNB a minor one. CCAs with IPNB showed a favorable postoperative OS compared to CCAs with high-grade BilIN.

An S100P-positive biliary epithelial field is a preinvasive intraepithelial neoplasm in nodular-sclerosing cholangiocarcinoma

Nodular-sclerosing cholangiocarcinoma (NS-CCA) is a common CCA of the intrahepatic large, perihilar, and distal bile ducts. Intraepithelial biliary neoplasms, such as the mucosal extension of carcinoma and preinvasive neoplastic lesions (ie, biliary intraepithelial neoplasia) reportedly occur in the bile ducts around CCA. In the present study, we collectively refer to these intraepithelial lesions as "intraepithelial neoplasms of the bile duct (IENBs)". We examined the IENBs in 57 surgically resected cases of NS-CCA. S100P immunostaining was used to help detect IENBs. The IENBs formed field(s) of continuous neoplastic biliary epithelial cells and showed a flat, micropapillary, or papillotubular configuration. IENBs could be classified into 3 categories based on their atypia: group A (neoplastic but not enough for malignancy), B (neoplastic and sufficiently well differentiated for high-grade dysplasia), and C (overtly malignant and variably differentiated). IENB was found in 31 of 57 cases, with group C the most common (26 cases) followed by group B (22 cases) and group A (16 cases). The expression of cancer-related molecules and MIB-1 index of groups A and B differed from those of invasive CCA, whereas these features of group C were relatively similar to those of invasive CCA. In conclusion, IENB was not infrequently found in NS-CCA and could be classified into 3 grades. Preinvasive lesions (biliary intraepithelial neoplasias) are likely to be found in groups A and B, whereas cancerization would be included in group C. The classification of IENB may be useful for future studies of the preinvasive intraepithelial neoplastic lesions of NS-CCAs.

Pathological diagnosis of flat epithelial lesions of the biliary tract with emphasis on biliary intraepithelial neoplasia

Flat epithelial lesions of the biliary tract cannot be detected by the image analysis, and the diagnosis entirely depends on pathological examination. The biliary tract is often affected by inflammatory conditions, and the resultant changes of the biliary epithelium make it difficult to differentiate them from neoplasia. Thus, the pathological diagnosis of biliary flat epithelial lesions can be challenging. In the biliary tract, there are several forms of intraepithelial neoplasia of the flat type, and biliary intraepithelial neoplasia (BilIN) is known as one of such lesions that represent the multistep cholangiocarcinogenesis. In this article, the diagnostic criteria and the differential diagnosis of biliary flat epithelial lesions, particularly focusing on BilIN, were presented and discussed to provide help to advance clinical and research applications of the BilIN system.

Histological characteristics of biliary intraepithelial neoplasia-3 and intraepithelial spread of cholangiocarcinoma

The increasing grades of biliary intraepithelial neoplasia (BilIN) reflect multistep carcinogenesis of cholangiocarcinoma, BilIN-3 representing the carcinoma in situ stage. A different form of in situ growth form of cancer cells is the intraepithelial spreading of cholangiocarcinoma cells. We examined the histological characteristics of carcinoma in situ in the biliary tract on 64 partial hepatectomy specimens with a diagnosis of hepatolithiasis. We distinguished two forms of carcinoma in situ: BilIN-3 and intraepithelial spread of carcinoma (IES). BilIN-3 is defined by epithelial atypia gradually decreasing towards the transition to adjacent normal biliary epithelium. In IES, the lesion shows an abrupt transition to normal biliary epithelium, in which the intraepithelial carcinoma then tends to spread. BilIN-3 and IES were observed in 17 (94 %) and seven (39 %), respectively, in cases of invasive cholangiocarcinoma (n = 18), and neither of them was observed in cases without invasive cholangiocarcinoma (n = 46). Most lesions of BilIN-3 and IES microscopically showed a flat or pseudopapillary pattern. The less frequent micropapillary configuration was noted more often in BilIN-3. BilIN-3 was not observed in septal and small intrahepatic bile ducts, while IES was regularly observed in such bile ducts. Immunohistochemical analysis showed p53 to be expressed significantly more frequently in IES (29 %) than in BilIN-3 (8 %). In conclusion, carcinoma in situ in the biliary tract is morphologically heterogeneous, and it is important to distinguish BilIN-3 and intraepithelial carcinoma spreading as distinct lesions, to better understand their biology.

Clinicopathologic study of intrapancreatic cancer spread in carcinoma of the body and tail of the pancreas

OBJECTIVE

The aims of this study were to clarify the type of intrapancreatic spread of cancer of the pancreatic body and tail and to assess whether a 2-cm transection margin is adequate to ensure negative margins.

METHODS

We selected 66 patients who underwent distal pancreatectomy for cancer of the pancreatic body and tail. We investigated intrapancreatic cancer spread in these patients histopathologically and analyzed the relationship between 2-cm-margin positivity and other clinicopathological characteristics.

RESULTS

Two-centimeter-margin positivity was observed in 17 cases. In these, tumors had a tendency to spread toward the pancreatic head along the main pancreatic duct. As a result of statistical analysis, we considered venous invasion (odds ratio [OR], 15.48; 95% confidence interval [CI], 1.61-148.94; P = 0.0177), 2-cm-margin fibrosis (OR, 173.88; 95% CI, 8.96-3375.03; P = 0.0007), and 2-cm-margin hardness (OR, 5.97; 95% CI, 1.07-33.46; P = 0.0420) as being independently related to 2-cm-margin positivity.

CONCLUSIONS

The results suggest that 2 cm is not a safe length to ensure a negative margin. In the future, preoperative and intraoperative evaluation of the degree of fibrosis of pancreatic parenchyma could lead to cancer-free pancreatic cut-end margins.

Invasive ductal carcinoma of the pancreas tail with noninvasive growth through the nondilated main pancreatic duct and macroscopically cystic invasive carcinomatous glands

Noninvasive growth forming macroscopically dilated cystic pancreatic ducts is a fundamental feature of intraductal papillary mucinous neoplasm (IPMN), from which invasive carcinomas can arise. However, some invasive ductal carcinomas of the pancreas also show a macroscopically cystic feature. We experienced 2 cases of invasive ductal carcinoma of the pancreas tail with noninvasive growth through the main pancreatic duct without dilation at the body side, and with collection of macroscopically cystic carcinomatous glands infiltrating at the spleen side, which resembled some IPMNs and/or IPMN-derived invasive carcinomas. These cases were different from IPMN in that they lacked macroscopic dilatation of the pancreatic ducts, and the macroscopically dilated cystic carcinomatous glands were invasive but not intraductal. The intraductal component of the carcinomas showed papillary growth of neoplastic epithelia with atypia consistent with PanIN-3. Both intraductal and invasive components predominantly showed gastric mucin phenotype (MUC5AC+, MUC6 focally +, MUC2- or MUC2+ in scattered small number of cells). Recognition of these pancreatic carcinoma cases is important in the following 2 points: (1) The presence of such cases should always be kept in mind as differential diagnosis of IPMN or IPMN-derived invasive carcinoma in imaging and pathologic diagnoses. (2) The histogenesis of these cases might be placed in the intermediate between 2 major histogenetic pathways of pancreatic carcinoma, that is, one from microscopic precursors called PanIN and the other from macroscopic precursors of IPMN. These cases can be regarded as invasive carcinomas derived from semimacroscopic extension of the intraductal lesion of the main pancreatic duct.

Invasive ductal adenocarcinoma of the pancreas may originate from the larger pancreatic duct: a study of 13 tumors less than 2 cm in diameter

BACKGROUND/PURPOSE

We aimed to elucidate the origin/primary site of invasive ductal adenocarcinoma of the pancreas, based on the distribution of intraductal carcinoma components. These components were identified by a mural elastic fiber cuff.

METHODS

Thirteen specimens from patients with invasive ductal adenocarcinoma (microscopically, less than 2 cm in diameter) of the pancreas were studied histopathologically. Variants of invasive ductal adenocarcinoma and intraductal papillary-mucinous carcinoma were excluded.

RESULTS

Intraductal carcinoma components of invasive ductal adenocarcinoma were found in 12 of the specimens 13 (92%), and were observed within the tumor mass and/or on its boundary, or outside the tumor mass. Intraductal components were characterized by low papillary projections lacking a fibrovascular core, with/without surrounding tubular structures, or by irregular stratification and pleomorphism of the epithelial cells. Invasive components mostly showed a tubular pattern with desmoplasia. The distribution of the intraductal components in the 12 specimens was as follows: in 9 (75%), they were in both the main pancreatic duct and large branch ducts; and in 3, they were in the smaller branch ducts only.

CONCLUSIONS

Invasive ductal adenocarcinomas of the pancreas may originate most frequently from the main pancreatic duct or larger branch ducts, while the smaller ducts are less often the site of cancer origin.