Intraductal tubulopapillary neoplasm (ITPN) of the pancreas: a distinct entity among pancreatic tumors

AIMS

Intraductal tubulopapillary neoplasm (ITPN) of the pancreas is a recently recognized pancreatic tumor entity. Here we aimed to determine the most important features with a systematic review coupled with an integrated statistical approach.

METHODS AND RESULTS

PubMed, SCOPUS, and Embase were searched for studies reporting data on pancreatic ITPN. The clinicopathological, immunohistochemical, and molecular data were summarized. Then a comprehensive survival analysis and a comparative analysis of the molecular alterations of ITPN with those of pancreatic ductal adenocarcinoma (PDAC) and intraductal papillary mucinous neoplasm (IPMN) from reference cohorts (including the International Cancer Genome Consortium- ICGC dataset and The Cancer Genome Atlas, TCGA program) were conducted. The core findings of 128 patients were as follows: (i) Clinicopathological parameters: pancreatic head is the most common site; presence of an associated adenocarcinoma was reported in 60% of cases, but with rare nodal metastasis. (ii) Immunohistochemistry: MUC1 (>90%) and MUC6 (70%) were the most frequently expressed mucins. ITPN lacked the intestinal marker MUC2; unlike IPMN, it did not express MUC5AC. (iii) Molecular landscape: Compared with PDAC/IPMN, the classic pancreatic drivers KRAS, TP53, CDKN2A, SMAD4, GNAS, and RNF43 were less altered in ITPN (P < 0.001), whereas MCL amplifications, FGFR2 fusions, and PI3KCA mutations were commonly altered (P < 0.001). (iv) Survival analysis: ITPN with a "pure" branch duct involvement showed the lowest risk of recurrence.

CONCLUSION

ITPN is a distinct pancreatic neoplasm with specific clinicopathological and molecular characteristics. Its recognition is fundamental for its clinical/prognostic implications and for the enrichment of potential targets for precision oncology.

A Review of Mucinous Cystic and Intraductal Neoplasms of the Pancreatobiliary Tract

CONTEXT.—

Although most pancreatic and bile duct neoplasms are solid, mucinous cystic neoplasms and intraductal neoplasms have been increasingly recognized even when clinically silent, thanks to the increased use of sensitive imaging techniques. Cystic and intraductal neoplasms of the pancreas are often resectable and curable and constitute about 5% of all pancreatic neoplasms. Owing to their preinvasive nature and different biology, recognition of these entities remains a major priority. Mucinous cystic neoplasms are histologically and clinically distinct from other cystic pancreatic neoplasms. Pancreatic intraductal neoplasms encompass 3 major entities: intraductal papillary mucinous neoplasm, intraductal oncocytic papillary neoplasm, and intraductal tubulopapillary neoplasm. Intraductal papillary neoplasms of bile ducts are also preinvasive mass-forming neoplasms with both similarities and differences with their pancreatic counterparts. All of these pancreatobiliary neoplasms have diverse and distinctive clinicopathologic, genetic, and prognostic variations.

OBJECTIVE.—

To review the clinical, pathologic, and molecular features of mucinous cystic and intraductal neoplasms of the pancreatobiliary tract.

DATA SOURCES.—

Literature review, diagnostic manuals, and guidelines.

CONCLUSIONS.—

This review will briefly describe well-known clinical and pathologic features and will focus on selected recently described aspects of morphology, grading, classification, and genomic alterations of cystic and intraductal neoplasms of the pancreatobiliary tract.

A resected case of focal autoimmune pancreatitis with pancreatic duct wall thickening representing periductal lymphoplasmacytic infiltrate

This case revealed that branch pancreatic duct wall thickening by endoscopic ultrasonography represented periductal lymphoplasmacytic infiltrate as a characteristic histopathological finding of autoimmune pancreatitis, which may help in the diagnosis of autoimmune pancreatitis. An 80-year-old man was referred because fluorodeoxyglucose-positron emission tomography for lung cancer indicated abnormal uptake in the pancreatic head. Computed tomography showed an enhanced mass with cystic structures in the pancreatic head. Magnetic resonance cholangiopancreatography revealed mild dilatation of the main pancreatic duct in the pancreatic body with no strictures. Endoscopic ultrasonography demonstrated a lobulated heterogeneous hypoechoic mass in the pancreatic head. A branch pancreatic duct with wall thickening connected the mass to the main pancreatic duct. An intraductal neoplasm filling and spreading into the branch pancreatic duct was considered, and surgery was performed. Histopathologically, the mass consisted of marked inflammatory cell infiltration, storiform fibrosis, and obliterative phlebitis. The branch pancreatic duct with wall thickening revealed a band-like inflammatory cell infiltration with mainly lymphocytes and plasma cells beneath the normal pancreatic duct epithelium. Immunohistological staining revealed abundant IgG4-positive plasma cells (> 10 cells/HPF) in the inflammatory cell infiltration. The definite diagnosis was type 1 focal autoimmune pancreatitis.

Intraductal Tubulopapillary Neoplasm of the Pancreas: A Clinicopathologic and Immunohistochemical Analysis of 33 Cases

Intraductal tubulopapillary neoplasm (ITPN) is a relatively recently described member of the pancreatic intraductal neoplasm family. Thus, the literature on its histologic and immunohistochemical features, clinical behavior, and its similarities and differences from other pancreatic neoplasms is limited. Thirty-three cases of ITPN, the largest series to date, were identified. Immunohistochemical labeling for cytokeratins, glycoproteins, pancreatic enzymes, markers for intestinal and neuroendocrine differentiation, and antibodies associated with genetic alterations previously described in pancreatic neoplasms was performed. Clinicopathologic features and survival was assessed. Seventeen patients were female and 14 were male. Mean age was 55 years (range, 25 to 79 y). Median overall tumor size was 4.5 cm (range, 0.5 to 15 cm). Forty-five percent of the tumors occurred in the head, 32% in the body/tail, and 23% showed diffuse involvement. Microscopically, the tumors were characterized by intraductal nodules composed of tightly packed small tubular glands lined by cuboidal cells lacking apparent mucin. Although it was often challenging to determine its extent, invasion was present in 71%. Almost all tumors labeled for CAM5.2, CK7, and CK19; most expressed CA19.9, MUC1, and MUC6. CDX2, MUC2, trypsin, chymotrypsin, chromogranin, and synaptophysin were not expressed. SMAD4 expression was retained in 100%; p16 expression and p53 overexpression was seen in 33% and 27%, respectively. Follow-up information was available for 22 patients (median follow-up, 45 mo; range, 11 to 173 mo). Two patients with invasive carcinoma died of disease at 23 and 41 months, respectively. One patient died of unrelated causes at 49 months. Twelve patients were alive with disease. Seven patients were alive with no evidence of disease. The overall 1-, 3-, and 5-year survival rates were 100% in patients without an invasive component and 100%, 91%, and 71%, respectively, in patients with an invasive component (P=0.7). ITPN is a distinct clinicopathologic entity in the pancreas. Despite the difficulties of determining the extent of invasive carcinoma in many cases, the overall outcome seems to be relatively favorable and substantially better than that of conventional pancreatic ductal adenocarcinoma, even when only the cases with invasive carcinoma are considered.

Clinicopathological features and surgical outcomes of intraductal tubulopapillary neoplasm of the pancreas: a systematic review

BACKGROUND AND AIMS

Intraductal tubulopapillary neoplasms (ITPNs) of the pancreas are rare. The purpose of this study was to collate and analyze published data on ITPNs of the pancreas to determine the clinicopathological features of the tumors and the surgical outcomes of patients.

PATIENTS AND METHODS

We searched MEDLINE and Igakuchuo-Zasshi for the period of 1980 to 2015 for case reports on surgical resection for ITPN of the pancreas. We evaluated the clinicopathological data associated with pancreatic ITPNs, the prognosis for each patient, and surgical outcomes described in the case reports.

RESULTS

We obtained clinicopathological data for 58 patients (33 men and 25 women) with a mean age of 61 years (range, 35-84 years) who had undergone surgical resection for ITPN of the pancreas, including one patient from our clinic. Although ITPNs of the pancreas have different clinicopathological features to intraductal papillary mucinous neoplasms, the treatment strategy for patients with ITPNs is the same as for patients with other cystic neoplasms of the pancreas. The immunohistochemical features of ITPNs included testing positive for cytokeratin 7 and/or cytokeratin 19 and negative for trypsin, MUC2, MUC5AC, and fascin. The overall 1-, 3-, and 5-year survival rates after surgery for the 37 cases with available data were 97.3, 80.7, and 80.7 %, respectively.

CONCLUSION

Surgical treatment is the only curative management option for patients with ITPN of the pancreas. To determine the best management strategy for this tumor and improve accuracy of prognosis for patients, we will continue to collect and analyze epidemiological and pathological data.

Intraductal tubulopapillary neoplasms of the pancreas: case report and review of the literature

A 69-year-old woman was referred to our hospital after incidental identification of a pancreatic mass during follow-up for diabetes mellitus. Various imaging examinations showed a tumor in the main pancreatic duct, without apparent hypersecretion of mucin. Brush cytologic examination revealed class V disease (adenocarcinoma). Because preoperative examination suggested an intraductal neoplasm with associated invasive cancer, total pancreatectomy was performed. Histological examination, based on current World Health Organization classifications, suggested a diagnosis of intraductal tubulopapillary neoplasm. A small cystic lesion adjacent to the intraductal tubulopapillary neoplasm was incidentally diagnosed as serous cystadenoma. The patient has remained well without recurrence as of 24 months postoperatively. Computed tomography and magnetic resonance imaging of the intraductal tubulopapillary neoplasm suggested ductal cell carcinoma of the pancreas rather than intraductal papillary mucinous neoplasm. Distinguishing intraductal tubulopapillary neoplasm from ductal cell carcinoma is clinically important, as intraductal tubulopapillary neoplasm has a favorable prognosis after curative resection.

Classification, morphology and molecular pathology of premalignant lesions of the pancreas

Over the past few years there have been substantial advances in our knowledge of premalignant lesions of the pancreas. Given the dismal prognosis of untreated pancreatic cancer, and the small proportion of patients who are operative candidates, an understanding of these premalignant lesions is essential for the development of strategies for early diagnosis and prevention. The 2010 WHO classification has added new entities, including intraductal tubular papillary neoplasms (ITPNs), and clarified the nomenclature and grading of previously recognised precursor lesions of pancreatic adenocarcinoma, such as intraductal papillary mucinous neoplasms (IPMNs), mucinous cystic neoplasms (MCNs) and pancreatic intraepithelial neoplasia (PanIN). In particular, there has been an upsurge of interest in the natural history of IPMN, driven partly by improvements in imaging modalities and the consequent apparent increase in their incidence, and partly by recognition that subtypes based on location or histological appearance define groups with significantly different behaviours. In mid 2012 revised international guidelines for the classification and management of IPMNs and MCNs were published, although in several respects these guidelines represent a consensus view rather than being evidence-based. In recent years major advances in molecular technologies, including whole-exome sequencing, have significantly enhanced our knowledge of pancreatic premalignancy and have identified potentially highly specific diagnostic biomarkers such as mutations in GNAS and RNF43 that could be used to pre-operatively assess pancreatic cysts.

Intraductal tubulopapillary neoplasm of the pancreas on fine needle aspiration: case report with differential diagnosis

Intraductal tubulopapillary neoplasm (ITPN) is a rare primary pancreatic neoplasm accounting for less than 1% of all pancreatic exocrine neoplasms and 3% of intraductal neoplasms of the pancreas. Data on this entity are still limited. Here, we report a case of ITPN with cytopathologic and histopathologic findings. A 41-year-old woman with a 2.2 cm cyst in the head of the pancreas for five years was referred to our institution. The endoscopic ultrasound-guided fine-needle aspiration produced cytospins were moderately cellular with a few fragments of markedly atypical epithelium. The neoplastic cells displayed high-grade nuclear atypia with enlarged, eccentric nuclei, anisonucleosis and prominent nucleoli, irregular nuclear membranes, high nucleus to cytoplasmic (N/C) ratios, and a moderate amount of cytoplasm with no intracytoplasmic mucin. Histologically, the lesion was found to be an ITPN with focal high-grade dysplasia. No invasive carcinoma was identified. The neoplastic cells exhibited luminal immunolabeling for MUC-1, but were negative for MUC-2, trypsin, chymotrypsin, and P53. Approximately 5% of the neoplastic cells showed Ki-67 immunoreactivity. ITPN of pancreas may be a source of markedly atypical epithelial cells in pancreatic cystic aspiration. Clinical and radiographic findings, molecular mutational analysis, in combination with cytological features are essential to differentiate it from other disease entities.

Intraductal tubular neoplasm of the common bile duct

Recently, biliary neoplasms resembling intraductal neoplasms of the pancreas have been documented. In this report, a rare case of intraductal tubular neoplasm (ITN) arising in the common bile duct is presented. A polypoid mass, 10 mm in diameter, was found in a 67-year-old woman in the intrapancreatic part of the common bile duct during the follow up to cholecystolithiasis and choledocholithiasis. Endoscopic polypectomy was performed for the lesion. Histology of the lesion revealed tubular neoplasm, composed of an admixture of tubular glands resembling pyloric gland adenoma with minimal atypia (low-grade tubular adenoma), and those resembling intestinal type tubular adenoma (high-grade tubular adenoma). There was no significant formation of papillae or oncocytic cytoplasm. Small foci of carcinoma in situ of the intestinal type were also observed. On immunostaining low-grade tubular adenoma was positive for MUC5AC and MUC6, and negative for MUC2 and cytokeratin (CK) 20, while high-grade tubular adenoma and carcinoma in situ were positive for MUC2 and CK20, and negative for MUC5AC. Although more case studies of ITN in the biliary tracts are required to clarify the tumorigenesis and pathological features, the lesion may be the biliary counterpart to pancreatic ITN.

Intraductal oncocytic papillary neoplasms of the pancreas and bile ducts: a description of five new cases and review based on a systematic survey of the literature

BACKGROUND

Intraductal oncocytic papillary neoplasms (IOPN) are rare tumors of the pancreatic and biliary ductal system. It is not absolutely clear if the molecular and clinicopathologic characteristics of IOPN differ significantly from other related lesions, namely intraductal papillary mucinous neoplasms (IPMN). Therefore it is not clear if it is reasonable to consider IOPN as a separate diagnostic and clinical entity.

METHODS

In order to describe the clinicopathologic characteristics of IOPN and to compare them with the IPMN profile, we performed a systematic review of the literature and additionally studied five previously unreported IOPN cases.

RESULTS

IOPN differ from IPMN by lack of K-ras gene mutations in all studied cases. Several differences in the clinical and biological profile between IOPN and IPMN exist, but they are of quantitative rather than of qualitative nature. Additionally, pancreaticobiliary or gastric-foveolar IPMN components may coexist with IOPN component within a single lesion, which suggests at least a partial relation of the pathogenetic pathways of IPMN and IOPN. Importantly, the pathogenesis of accumulation of mitochondria and oxyphilic appearance of IOPN remains unknown.

CONCLUSIONS

At present, there are no reliable criteria other than histopathological picture and K-ras gene status to differentiate IOPN from IPMN. In particular, no clear differences in optimal treatment options and prognosis between these tumors are known. Further studies are needed to clarify the biology of IOPN and to establish their position in clinicopathologic classifications of pancreatic tumors.

Intraductal tubulopapillary neoplasms of the pancreas distinct from pancreatic intraepithelial neoplasia and intraductal papillary mucinous neoplasms

We have encountered cases of unusual intraductal pancreatic neoplasms with predominant tubulopapillary growth. We collected data on 10 similar cases of "intraductal tubulopapillary neoplasms (ITPNs)" and analyzed their clinicopathologic and molecular features. Tumor specimens were obtained from 5 men and 5 women with a mean age of 58 years. ITPNs were solid and nodular tumors obstructing dilated pancreatic ducts and did not contain any visible mucin. The tumor cells formed tubulopapillae and contained little cytoplasmic mucin. The tumors exhibited uniform high-grade atypia. Necrotic foci were frequently observed, and invasion was observed in some cases. The ITPNs were immunohistochemically positive for cytokeratin 7 and/or cytokeratin 19 and negative for trypsin, MUC2, MUC5AC, and fascin. Molecular studies revealed abnormal expressions of TP53 and SMAD4 in 1 case, but aberrant expression of beta-catenin was not observed. No mutations in KRAS and BRAF were observed in the 8 cases that were examined. Eight patients are alive without recurrence, 1 patient died of liver metastases, and 1 patient is alive but had a recurrence and underwent additional pancreatectomy. The mitotic count and Ki-67 labeling index were significantly associated with invasion. All the features of ITPN were distinct from those of other known intraductal pancreatic neoplasms, including pancreatic intraepithelial neoplasia, intraductal papillary mucinous neoplasm, and the intraductal variant of acinar cell carcinoma. Intraductal tubular carcinomas showed several features that were similar to those of ITPN, except for the tubulopapillary growth pattern. In conclusion, ITPNs can be considered to represent a new disease entity encompassing intraductal tubular carcinoma as a morphologic variant.

Intraductal tubular carcinoma of the pancreas: a case report with the imaging findings

We describe here a case of intraductal tubular carcinoma of the main pancreatic duct. Gadolinium-enhanced pancreas magnetic resonance (MR) imaging showed an enhancing mass that was confined in the dilated main pancreatic duct of the pancreatic body, along with dilatation of the upstream main pancreatic duct and chronic pancreatitis that was due to obstruction. MR cholangiopancreatography and an endoscopic retrograde pancreatogram showed a filling defect that was due to an intraductal mass of the pancreatic body, along with dilatation of the upstream main pancreatic duct and no dilatation of the downstream main pancreatic duct. The pathological findings demonstrated an intraductal nodular appearance without papillary projection or mucin hypersecretion.