Intraductal Tubulopapillary Neoplasm of the Pancreas: An Update From a Pathologist's Perspective

Adenocarcinoma in Intraductal Tubulopapillary Neoplasm of the Pancreas: A Case Report and Literature Review

Intraductal tubulopapillary neoplasms (ITPNs) are a subgroup of pre-malignant pancreatic epithelial lesions. The histomorphological and immunophenotypical characteristics of ITPN have been described by several authors based on case series; however, the rarity of this tumor subtype and its similarity to other entities makes the identification of ITPN challenging for radiologists and pathologists. Herein, we report a case of ITPN with associated invasive carcinoma along with a literature review that will benefit further studies and help in planning treatments for patients in the future. A pancreatic mass was incidentally discovered in a 40-year-old woman during her annual check-up. Radiological investigation revealed a mass that obstructed the main pancreatic duct and caused ductal dilatation. Endoscopic retrograde cholangiopancreatography with biopsy indicated poorly differentiated adenocarcinoma. Subsequently, total pancreatectomy with splenectomy was performed to remove the tumor. ITPN of the pancreas with associated poorly differentiated adenocarcinoma was diagnosed based on pathological and immunohistological test results. Achieving complete resection of the tumor, the patient did not require chemotherapy during follow-up care. Thus, our study demonstrated the necessity of radiological and histopathological correlation in the definitive diagnosis of pancreatic ITPN. However, the determination of an invasive component is essential because malignant transformation affects the prognosis of patients.

Imaging features of intraductal tubulopapillary neoplasm of the pancreas and its differentiation from conventional pancreatic ductal adenocarcinoma

Intraductal tubulopapillary neoplasms (ITPN) are rare pancreatic tumors (< 1% of exocrine neoplasms) and are considered to have better prognosis than classical pancreatic ductal adenocarcinoma (PDAC). The present study aimed to evaluate imaging features of ITPN in computed tomography (CT) and magnetic resonance (MR) imaging. We performed monocentric retrospective analysis of 14 patients with histopathologically verified ITPN, operated in 2003–2018. Images were available for 12 patients and were analysed independently by two radiologists, blinded to reports. Imaging features were compared to a matched control group consisting of 43 patients with PDAC, matched for sex and age. Histopathologic analysis showed invasive carcinoma component in all ITPN patients. CT-attenuation values of ITPN were higher in arterial and venous phases (62.3 ± 14.6 HU and 68 ± 15.6 HU) than in unenhanced phase (39.2 ± 7.9 HU), compatible with solid lesion enhancement. Compared to PDAC, ITPN lesions had significantly higher HU-values in both arterial and venous phases (arterial and venous phases, p < 0.001). ITPN were significantly larger than PDAC (4.1 ± 2.0 cm versus 2.6 ± 0.84 cm, p = 0.021). ITPN lesions were more often well-circumscribed (p < 0.002). Employing a multiple logistic regression analysis with forward stepwise method, higher HU density in the arterial phase (p = 0.012) and well-circumscribed lesion margins (p = 0.047) were found to be significant predictors of ITPN versus PDAC. Our study identified key imaging features for differentiation of ITPN and PDAC. Isodensity or moderate hypodensity and well-circumscribed margins favor the diagnosis of ITPN over PDAC. Being familiar with CT-features of these rare pancreatic tumors is essential for radiologists to accelerate the diagnosis and narrow the differentials.

Intraductal Papillary Mucinous Neoplasms in Hereditary Cancer Syndromes

Hereditary pancreatic cancer, which includes patients with familial pancreatic cancer (FPC) and hereditary pancreatic cancer syndromes, accounts for about 10% of all pancreatic cancer diagnoses. The early detection of pre-cancerous pancreatic cysts has increasingly become a focus of interest in recent years as a potential avenue to lower pancreatic cancer incidence and mortality. Intraductal papillary mucinous cystic neoplasms (IPMNs) are recognized precursor lesions of pancreatic cancer. IPMNs have high prevalence in patients with hereditary pancreatic cancer and their relatives. While various somatic mutations have been identified in IPMNs, certain germline mutations associated with hereditary cancer syndromes have also been identified in IPMNs, suggesting a role in their formation. While the significance for the higher prevalence of IPMNs or similar germline mutations in these high-risk patients remain unclear, IPMNs do represent pre-malignant lesions that need close surveillance. This review summarizes the available literature on the incidence and prevalence of IPMNs in inherited genetic predisposition syndromes and FPC and speculates if IPMN and pancreatic cancer surveillance in these high-risk individuals needs to change.

Diminished Immune Surveillance during Histologic Progression of Intraductal Papillary Mucinous Neoplasms Offers a Therapeutic Opportunity for Cancer Interception

PURPOSE

Intraductal papillary mucinous neoplasms (IPMN) are bona fide precursors to pancreatic ductal adenocarcinoma (PDAC). While genomic alterations during multistep IPMN progression have been well cataloged, the accompanying changes within the tumor immune microenvironment (TIME) have not been comprehensively studied. Herein, we investigated TIME-related alterations during IPMN progression, using multiplex immunofluorescence (mIF) coupled with high-resolution image analyses.

EXPERIMENTAL DESIGN

Two sets of formalin-fixed, paraffin-embedded tissue samples from surgically resected IPMNs were analyzed. The training set of 30 samples consisted of 11 low-grade IPMN (LG-IPMN), 17 high-grade IPMN (HG-IPMN), and 2 IPMN with PDAC, while a validation set of 93 samples comprised of 55 LG-IPMN and 38 HG-IPMN. The training set was analyzed with two panels of immuno-oncology-related biomarkers, while the validation set was analyzed with a subset of markers found significantly altered in the training set.

RESULTS

Cell types indicative of enhanced immune surveillance, including cytotoxic and memory T cells, and antigen-experienced T cells and B cells, were all found at higher densities within isolated LG-IPMNs compared with HG-IPMNs. Notably, the TIME of LG-IPMNs that had progressed at the time of surgical resection (progressor LGD) resembled that of the synchronous HG-IPMNs, underscoring that attenuated immune surveillance occurs even in LG-IPMNs destined for progression.

CONCLUSIONS

Our findings provide a basis for interception of cystic neoplasia to PDAC, through maintenance of sustained immune surveillance using vaccines and other prevention approaches.

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.

Intestinal Autotransplantation and In-Situ Resection of Recurrent Pancreatic Head Intraductal Tubulopapillary Neoplasm with Portal Cavernoma: A Case Report

BACKGROUND

Intraductal tubulopapillary neoplasm (ITPN) is a new entity of a rare premalignant pancreatic neoplasia, and a radical curative resection is indicated. As with other tumors of the root of the mesentery, the proximity of the lesion to large splanchnic vessels, abdominal aorta, and inferior vena cava poses major risks of a massive hemorrhage and visceral ischemia using conventional surgical techniques. At times, these lesions are amenable for resection using novel techniques developed from organ transplantation. Multivisceral (allo-) transplantation should be considered when radical resection of a benign tumor is likely to compromise portal flow and possibly precipitate acute liver failure, but it may be associated with a long waitlist time and tumor progression. Autotransplantation offers a safe and curative resection of otherwise inoperable tumors in a bloodless field, an excellent exposure, and prevention of warm ischemic injury to the affected viscera, which are then autotransplanted.

METHODS

We describe the en bloc resection of a large and recurrent ITPN of the pancreas, distal stomach, proximal duodenum, transverse colon, superior mesenteric vein, and portal cavernoma, followed by intestinal autotransplantation.

RESULTS

A complete tumor resection was achieved with negative margins, adequate cold preservation of the reimplanted intestine, and without significant hemorrhage. The patient was discharged from the hospital 10 days later. The histopathologic examination revealed free-margin resection of ITPN with an associated invasive carcinoma. The patient received adjuvant chemotherapy with folinic acid, fluorouracil, and oxaliplatin and remains disease-free 20 months after surgery.

CONCLUSIONS

Autotransplantation offers curative resection of otherwise unresectable lesions of the root of the mesentery.

Total Pancreatectomy with Splenectomy for Multifocal Intraductal Tubulopapillary Neoplasm (ITPN) of the Pancreas Associated with Invasive Component: Report of a Rare Case

Patient: Male, 82-year-old

Final Diagnosis: Pancreatic intraductal tubulopappilary neoplasm (ITPN)

Symptoms: Abdominal pain • anorexia • weakness • weight loss

Medication: Amlodipine 5 mg/valsartan 160 mg • nebivolol 5 mg • metformin 850 mg • pancreatin 25 000 IU

Clinical Procedure: Total pancreatectomy with splenectomy

Specialty: Oncology • Pathology • Radiology • Surgery

Intraductal Tubulopapillary Neoplasm of the Pancreas Presenting as a Localized Pancreatic Tumor in a 52-Year-Old Woman: Focusing on a Rare Pancreatic Malignancy and Contrasting to Intrapapillary Mucinous Neoplasm

Intraductal tubulopapillary neoplasm (ITPN) is a distinctive type of pancreatic tumor first discovered more than three decades ago. ITPNs currently account for less than 1% of all pancreatic exocrine tumor cases recognized, and less than 5% of pancreatic intraductal tumors. A patient's presentation is often nonspecific in comparison to other intraductal pancreatic neoplasms. We discuss a 52-year-old female presenting with abdominal pain and weight loss with ITPN, and go on to define the typical presentation, clinical features, and pathology behind the tumor.

Intraductal Tubulopapillary Neoplasm of the Pancreas and Bile Duct: A Review

Intraductal tubulopapillary neoplasms (ITPNs) of the pancreas and bile duct are contemporary entities. It is unclear on how to best manage patients with this diagnosis because little is known about its progression to cancer. This review provides an update on the current knowledge of ITPN of the pancreas and bile duct with an overview of clinical, radiological, histopathological, and molecular features, as well as the prognosis and management. Embase and Medline databases search were performed to identify studies that evaluated ITPN of the pancreas and bile duct. The infrequent exposure to this variant poses a diagnostic challenge. The diagnosis of ITPN is almost always made postoperatively because there are no characteristics on radiological studies to distinguish it from other cystic neoplasms of the pancreas. As ITPN has a favorable prognosis, it is crucial to establish an accurate diagnosis and differentiate it from other pancreatic and biliary variants. These neoplasms are considered to be precursor lesions to carcinomas, hence, surgery and close clinical surveillance are recommended. Further studies are essential to elucidate the natural history of ITPN, guide best treatment strategy and determine disease recurrence and survival.

Multimodality imaging studies of intraductal tubulopapillary neoplasms of the pancreas

PURPOSE

We aimed to investigate multimodality imaging findings of intraductal tubulopapillary neoplasms (ITPN) of the pancreas.

METHODS

This study was approved by the institutional review board with waived informed consent. A total of eight patients were histopathologically diagnosed with pancreatic ITPN in a single institution over a 6-year period. The imaging findings of dynamic contrast-enhanced computed tomography (CT), magnetic resonance cholangiopancreatography (MRCP), endoscopic ultrasonography (EUS), and positron emission tomography-computed tomography (PET-CT) were reviewed and correlated with clinicopathologic findings.

RESULTS

Histopathologically, an invasive carcinoma component was found in 5 of 8 patients (62.5%). The median diameter of the lesions and the main pancreatic ducts were larger in ITPN with invasive carcinoma (19 mm, 13.3-98.0 mm and 13 mm, 5.9-16.3 mm, respectively) than in ITPN without invasive carcinoma (13 mm, 12.7-18.5 mm and 6 mm, 5.6-6.1 mm, respectively), but not significantly (lesions, P = 0.229 and main pancreatic ducts, P = 0.143). Pancreatolithiasis accompanied invasive carcinoma in 3 of 5 patients (60%). Intraductal solid tumors were demonstrated on CT (5/8, 62.5%), MRCP (5/7, 71.4%), and EUS (7/7, 100%). In addition, various imaging findings mimicking chronic autoimmune pancreatitis or pancreatic ductal adenocarcinoma were found in 3 patients (37.5%) on multimodality imaging. The lesion multiplicity and synchronous or metachronous biliary cancer occurred in 3 patients (37.5%), respectively.

CONCLUSION

Patients with associated invasive carcinoma from pancreatic ITPN may have presented a trend toward larger tumor size and dilated pancreatic duct with pancreatoliths, but the difference was not statistically significant. Further studies with a larger number of patients are needed to provide better insight into these findings. Pancreatic ITPN can show various atypical imaging findings as well as typical intraductal solid tumor on multimodality imaging. The presence of lesion multiplicity and synchronous or metachronous biliary cancer can be helpful for assisting with the diagnosis of pancreatic ITPN.

Pancreatic Ductal Adenocarcinoma and Its Precursor Lesions: Histopathology, Cytopathology, and Molecular Pathology

Pancreatic ductal adenocarcinoma is one of the most aggressive malignant neoplasms with poor outcomes. At the time of diagnosis, the disease is usually at an advanced stage and only a minority is eligible for surgical resection. To improve the prognosis, it is essential to diagnose and treat the disease in an early stage before its progression into an invasive disease. This article reviews clinical features, histopathology, cytopathology, and molecular alterations of pancreatic ductal adenocarcinoma and its precursors. Moreover, we review a recently updated two-tier classification system for precursor lesions, new findings in premalignant cystic neoplasms, and recently updated staging criteria for invasive carcinoma based on the Cancer Staging Manual, eighth edition, from the American Joint Committee on Cancer. Finally, we discuss the potential clinical applications of the rapidly growing molecular and genetic information of pancreatic cancer and its precursors.

A rare case of intraductal tubulopapillary neoplasm of the pancreas - case report (with video)

Intraductal tubulopapillary neoplasm (ITPN) is a premalignant epithelial tumor of the pancreas. We report a case of ITPN detected incidentally during histopathology examination (HPE) from a specimen taken at the time of endosonography in a patient with pancreatitis. A 53-year-old man presented with severe recurrent epigastric pain, associated with episodic nonbilious vomiting, with a weight loss of about 7 Kg since 15 days. He underwent Magnetic resonance cholangiopancreatography which showed an ovoid soft tissue lesion in the Pancreatic duct (PD) reported as possible intraductal neoplasm. Patient underwent Endoscopic Ultrasound, whereby the PD was dilated and a large hypoechoic lesion was noted in the PD (head region) causing upstream dilatation. Lesion did not show any vascularity on Doppler. Fine needle biopsy was sent from the intraductal lesion for histopathology examination (HPE). Patient then underwent an ERCP. After performing a pancreatic sphincterotomy, pancreaticoscopy was done using SPYGLASS DS system which showed a nodular intraluminal lesion in the head region with irregular and abnormal vascularity and papillary fronds. Biopsies were taken from this lesion using SpyBite biopsy forceps. To our surprise this HPE report came out to be ITPN. Patient was then referred for surgery. There is often a difference of opinion in distinguishing and classifying such tumors when compared to the subtypes of mucinous neoplasm. Identification of this neoplasm is often challenging for pathologists as well as radiologists. We present this case since it is infrequent and atypical in routine medical practice.

Deciphering DNA methylation signatures of pancreatic cancer and pancreatitis

BACKGROUND

Chronic pancreatitis presents a high risk of inflammation-related progression to pancreatic cancer. Pancreatic cancer is the fourth leading cause of cancer-related death worldwide. The high mortality rate is directly related to the difficulty in promptly diagnosing the disease, which often presents as overt and advanced. Hence, early diagnosis for pancreatic cancer becomes crucial, propelling research into the molecular and epigenetic landscape of the disease.

MAIN BODY

Recent studies have shown that cell-free DNA methylation profiles from inflammatory diseases or cancer can vary, thus opening a new venue for the development of biomarkers for early diagnosis. In particular, cell-free DNA methylation could be employed in the identification of pre-neoplastic signatures in individuals with suspected pancreatic conditions, representing a specific and non-invasive method of early diagnosis of pancreatic cancer. In this review, we describe the molecular determinants of pancreatic cancer and how these are related to chronic pancreatitis. We will then present an overview of differential methylated genes in the two conditions, highlighting their diagnostic or prognostic potential.

CONCLUSION

Exploiting the relation between abnormally methylated cell-free DNA and pre-neoplastic lesions or chronic pancreatitis may become a game-changing approach for the development of tools for the early diagnosis of pancreatic cancer.

Imaging findings of intraductal tubulopapillary neoplasm (ITPN) of the pancreas: Two case reports and literature review

RATIONALE

Intraductal tubulopapillary neoplasm (ITPN) is a rare type of pancreatic epithelial neoplasm. We report 2 cases of ITPN and detail the imaging findings.

PATIENT CONCERNS

The 1st case was a 36-year-old woman who complained of jaundice, yellow urine and diarrhea. She accepted ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI) examination before surgery, which all revealed a mass in the pancreatic head. The 2nd case was a 62-year-old woman who was admitted to our hospital for the treatment of a pancreatic tumor. The MRI showed a mass filled the mian pancreatic duct in the head and neck.

DIAGNOSIS

The ITPN is an intraductal, grossly visible, tubule-forming epithelial neoplasm with high-grade dysplasia and ductal differentiation without overt mucin production.

INTERVENTIONS

The 1st patient received percutaneous transhepatic cholangial drainage procedure, endoscopic ultrasound guided fine needle aspiration, pancreatoduodenectomy, cholecystectomy, and lymphadenectomy successively. The 2nd patient received pancreaticoduodenectomy, cholecystectomy, and partial gastrectomy.

OUTCOMES

Two months after surgery, the follow-up MRI revealed hepatic metastasis of the 1st patient. She is still alive now. The 2nd patient was lost to follow-up.

LESSONS

The ITPN is a rare pancreatic neoplasm and its clinical symptoms are atypical. It is difficult to make accurate diagnosis of ITPN before surgery even though various imaging modalities are used in combination. When a solid mass growing in the lumen of the pancreatic duct, ITPN should be taken into consideration.

Rare pancreatic tumors

In this review, we will focus on rare pancreatic tumors. Most of these tumors do not have distinct characteristic appearances so the key to diagnosis requires a combination of imaging appearance, laboratory data, patient demographics, and associated medical syndromes in order to narrow the differential diagnosis. Nonetheless, imaging plays a vital role in narrowing the differential and guiding management. While there are many variant pathologic entities that cannot be encompassed by a single review, we aim to illustrate the imaging appearance of less common pancreatic tumors highlighting key distinctive diagnostic characteristics and discuss the implications for management. While there is overlap in the imaging appearances of many of these entities, for educational purposes, lesions will be categorized into solid (hypoenhancing and hyperenhancing), cystic lesions, mesenchymal neoplasms, and neoplasms seen in younger patients (< 40 years).

Classification, Morphology, Molecular Pathogenesis, and Outcome of Premalignant Lesions of the Pancreas

CONTEXT

- Invasive pancreatic ductal adenocarcinoma has a greater than 90% mortality rate at 5 years. Understanding noninvasive, curable precursor lesions gives us the best hope for reducing mortality from pancreatic ductal adenocarcinoma. The 3 pancreatic precursor lesions that have been well studied include intraductal papillary mucinous neoplasm, mucinous cystic neoplasm, and pancreatic intraepithelial neoplasia.

OBJECTIVE

- To give an update on the latest clinical, molecular, and pathologic advances in intraductal papillary mucinous neoplasm, mucinous cystic neoplasm, and pancreatic intraepithelial neoplasia for the general surgical pathologist.

DATA SOURCES

- The current literature was analyzed and the authors' experiences with institutional and consult material were incorporated.

CONCLUSIONS

- Our understanding of the molecular alterations that lead from pancreatic precursor lesion to invasive carcinoma continues to evolve. These advances aid clinicians in their treatment decisions and researchers in their search for actionable, druggable targets.

Pancreatic Cancer: Molecular Characterization, Clonal Evolution and Cancer Stem Cells

Pancreatic Ductal Adenocarcinoma (PDAC) is the fourth most common cause of cancer-related death and is the most lethal of common malignancies with a five-year survival rate of <10%. PDAC arises from different types of non-invasive precursor lesions: intraductal papillary mucinous neoplasms, mucinous cystic neoplasms and pancreatic intraepithelial neoplasia. The genetic landscape of PDAC is characterized by the presence of four frequently-mutated genes: KRAS, CDKN2A, TP53 and SMAD4. The development of mouse models of PDAC has greatly contributed to the understanding of the molecular and cellular mechanisms through which driver genes contribute to pancreatic cancer development. Particularly, oncogenic KRAS-driven genetically-engineered mouse models that phenotypically and genetically recapitulate human pancreatic cancer have clarified the mechanisms through which various mutated genes act in neoplasia induction and progression and have led to identifying the possible cellular origin of these neoplasias. Patient-derived xenografts are increasingly used for preclinical studies and for the development of personalized medicine strategies. The studies of the purification and characterization of pancreatic cancer stem cells have suggested that a minority cell population is responsible for initiation and maintenance of pancreatic adenocarcinomas. The study of these cells could contribute to the identification and clinical development of more efficacious drug treatments.

Intraductal tubulopapillary neoplasm (ITPN) of the pancreas associated with an invasive component: a case report with review of the literature

BACKGROUND

Intraductal tubulopapillary neoplasm (ITPN) depicts a distinct entity in the subgroup of premalignant epithelial tumors of the pancreas. Although the histomorphological and immunophenotypical characterization of ITPN has been described by several authors in terms of report of case series in the past, the rarity of that tumor subtype and similarity to other entities still makes identification of ITPN a challenge for radiologists and pathologists. To date, little is known about tubulopapillary carcinoma that can evolve from ITPN.

CASE PRESENTATION

In the present work, we analyze one case of ITPN associated with an invasive component and discuss the results involving the current literature. Collected patient data included medical history, clinical symptoms, laboratory tests, radiological imaging, reports of interventions and operation, and histopathological and immunohistochemical examinations. The patient initially presented with acute pancreatitis. A solid tumor obstructing the main pancreatic duct and sticking out of the papilla of Vater was detected and caught via endoscopic intervention. Histopathological examination of the specimen revealed mainly tubular growth pattern with back to back tubular glands. Immunohistochemically, the tumor was strongly positive for keratin 7 (CK7) and pankeratin AE1/AE3, and alpha 1 antichymotrypsin; negative for synaptophysin and chromogranin A, CDx2, CK20, S100, carcinoembryonic antigen (CEA), MUC 2, MUC5AC, and somatostatin; and in part positive for CA19-9. Extended pancreatoduodenectomy was performed, the final diagnosis was tubulopapillary carcinoma grown in an ITPN.

CONCLUSION

The identification of an ITPN of the pancreas can be a challenging task. Endoscopic retrograde cholangiopancreaticography is an excellent tool to directly see and indirectly visualize the intraductal solid tumor and to take a biopsy for histopathological evaluation at the same time. Together with a thorough immunohistochemical workup, differential diagnoses can be ruled out quickly. To date, reports of ITPN are rare and little is known about the potential for malignant transformation and the prognosis of tubulopapillary carcinoma grown from an ITPN. Radical surgical resection following oncologic criteria is recommended; however, more data will be needed to assess an adequate treatment and follow-up standard.

Comparative radiological pathological study of biliary intraductal tubulopapillary neoplasm and biliary intraductal papillary mucinous neoplasm

PURPOSE

Biliary tract intraductal tubulopapillary neoplasms (BT-ITPNs) and intraductal papillary mucinous neoplasms (BT-IPMNs) are rare and poorly described. Herein, we examined the magnetic resonance imaging (MRI) features of BT-ITPNs and BT-IPMNs and correlated them with key gross and microscopic pathological findings.

METHODS

We retrospectively identified five patients with definitive pathological findings of BT-ITPN and available diagnostic MRI findings. Key MRI features were correlated to the gross and microscopic pathology and compared to those of BT-IPMNs (19 patients).

RESULTS

All BT-ITPNs showed ductal dilatation and visible intraductal soft tissue with peribiliary liver parenchyma enhancement. One BT-ITPN patient had synchronous lung metastases, and another showed rapid tumor growth rate. The intraductal soft tissue proportion of BT-ITPNs was significantly more than that of BT-IPMNs (p < 0.05). CA-199 level was elevated in 60% of BT-ITPN cases. The overall combined 1-year and 3-year survival rates in the BT-ITPN group was 100% and 40%, and in the BT-IPMN group was 100% and 58%, respectively. A high intraductal soft tissue proportion, a lack of intraluminal mucin, and immunohistochemical absence of MUC5AC are radiological and pathological characteristics that differentiate BT-ITPN from BT-IPMN.

CONCLUSIONS

Although rare, BT-ITPN should be suspected when solid intraductal soft tissue and peribiliary liver parenchyma enhancement are present, particularly if the bile duct upstream and downstream of the lesion have a normal diameter, without mucin. Owing to the aggressive nature of the tumor, recognition of these features may indicate the need for more aggressive treatment in selected patients.