Simultaneous liver mucinous cystic and intraductal papillary mucinous neoplasms of the bile duct:A case report

Cystic hepatic neoplasms are rare tumors,and are classified into two separate entities:mucinous cystic neoplasms(MCNs)and intraductal papillary mucinous neoplasms of the bile duct(IPMN-B).We report the case of a 56-year-old woman who presented with abdominal pain and jaundice due to the presence of a large hepatic multilocular cystic tumor associated with an intraductal tumor.Partial hepatectomy with resection of extrahepatic bile ducts demonstrated an intrahepatic MCN and an intraductal IPMN-B.This is the first report of the simultaneous occurrence of these two histologically distinct entities in the liver.     

Intraductal papillary neoplasm of the bile duct developing in a patient with primary sclerosing cholangitis: A case report

We report a case of intraductal papillary neoplasm of the bile duct (IPNB) that developed in a patient with primary sclerosing cholangitis. A 46-year-old woman was admitted to our hospital with obstructive jaundice. The liver function tests demonstrated increased serum liver enzyme levels. Computed tomography showed dilatation of the intrahepatic bile ducts. Abdominal ultrasonography revealed a highly echoic protruding lesion in the posterior bile duct near the right lobe of the liver. The lesion was suspected to be IPNB, but we were unable to confirm whether it was a carcinoma. A right hepatectomy was performed, and this showed that the dilated bile duct was filled with mucin and contained several yellowish papillary tumors. Histologically, the neoplastic biliary epithelium showed papillary growth in the dilated lumen. The tumor was diagnosed as IPNB, high-grade intraepithelial neoplasia secreting abundant mucin. No recurrence has been detected 3 years after surgery.     

Mucin-producing bile duct tumors: radiological–pathological correlation and diagnostic strategy

Mucin-producing bile duct tumors are characterized by intraductal papillary tumors producing large amounts of mucin. The tumor comprises macroscopically prominent intraductal papillary neoplastic epithelia and produces a large amount of viscid mucin, resulting in dilatation of the bile ducts. The surface of the tumor is frond-like, velvety, or serrated. The tumor exhibits five intraductal growth patterns; polypoid intraductal growth, mucosal spreading growth, cast-like intraductal growth, cystic tumor, and intraductal floating tumors. Imaging features reflect the interplay between the morphology of the tumor, the amount of mucin production, and biliary dilatation. This review article describes the radiological manifestations of the tumor, based on pathological-radiological correlation and biological behavior.     

Intraductal papillary mucinous tumor of the pancreas: computerized tomography and magnetic resonance imaging features

The aim of this study was to analyze the computerized tomography (CT) and magnetic resonance imaging (MRI) features of intraductal papillary mucinous tumor (IPMT) of the pancreas. The cases of eight patients with pathologically proven IPMT (1 papillary hyperplasia, 7 adenocarcinoma) of the pancreas were retrospectively reviewed. There were five men and three women with ages ranging from 42 to 82 years. Imaging studies included six thin-section dynamic CT scans, seven MRI scans, one MR cholangiopancreatography scan, and two endoscopic retrograde cholangiopancreatography scans. There was only one benign IPMT, which presented as a unilocular cyst in the pancreatic body with no mural nodules and no dilatation of the main pancreatic duct (MPD). All seven patients with malignant IPMT had multilocular cysts with papillary projections in the pancreatic head and/or uncinate process accompanied by dilated MPD (5 diffuse, 2 segmental). Communication between the cystic lesions and the MPD were evident in all seven patients. One patient had small mural nodules in the branch ducts of the pancreatic body and five had a bulging papilla with a patulous orifice. A mass effect resulting in biliary obstruction was shown in one patient. One patient had a ruptured cyst with mucin leakage into the right anterior pararenal space following sono-guided aspiration. In conclusion, the main imaging feature of IPMT in our patients was a multilocular cyst with papillary projections located in the pancreatic head and uncinate process. Although CT and MRI cannot differentiate mucin content from pancreatic juice, communication between the cystic lesion and the dilated MPD and a bulging papilla with a patulous orifice are characteristics of IPMT.     

Gd-EOB-DTPA-enhanced magnetic resonance imaging features of hepatic hemangioma compared with enhanced computed tomography

AIM:To clarify features of hepatic hemangiomas on gadolinium-ethoxybenzyl-diethylenetriaminpentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) compared with enhanced computed tomography (CT). METHODS:Twenty-six patients with 61 hepatic hem- angiomas who underwent both Gd-EOB-DTPA-enhanced MRI and enhanced CT were retrospectively reviewed. Hemangioma appearances (presence of peripheral nodular enhancement, central nodular enhancement, diffuse homogenous enhancement, and arterioportal shunt during the arterial phase, fill-in enhancement during the portal venous phase, and prolonged enhancement during the equilibrium phase) on Gd-EOB-DTPA-enhanced MRI and enhanced CT were evaluated.The degree of contrast enhancement at the enhancing portion within the hemangioma was visually assessed using a five-point scale during each phase. For quantitative analysis, the tumor-muscle signal intensity ratio (SIR), the liver-muscle SIR, and the attenuation value of the tumor and liver parenchyma were calculated. The McNemar test and the Wilcoxon's signed rank test were used to assess the significance of differences in the appearances of hemangiomas and in the visual grade of tumor contrast enhancement between Gd-EOB-DTPA-enhanced MRI and enhanced CT. RESULTS:There was no significant difference between Gd-EOB-DTPA-enhanced MRI and enhanced CT in the presence of peripheral nodular enhancement (85% vs 82%), central nodular enhancement (3% vs 3%), diffuse enhancement (11% vs 16%), or arterioportal shunt (23% vs 34%) during arterial phase, or fill-in enhancement (79% vs 80%) during portal venous phase. Prolonged enhancement during equilibrium phase was observed less frequently on Gd-EOB-DTPA-enhanced MRI than on enhanced CT (52% vs 100%, P 0.001). On visual inspection, there was significantly less contrast enhancement of the enhancing portion on Gd-EOB-DTPA-enhanced MRI than on enhanced CT during the arterial (3.94 ± 0.98 vs 4.57 ± 0.64, respectively, P 0.001), portal venous (3.72 ± 0.82 vs 4.36 ± 0.53, respectively, P 0.001), and equilibrium phases (2.01 ± 0.95 vs 4.04 ± 0.51, respectively, P 0.001). In the quantitative analysis, the tumor-muscle SIR and the liver-muscle SIR observed with Gd-EOB-DTPA-enhanced MRI were 0.80 ± 0.24 and 1.28 ± 0.33 precontrast, 1.92 ± 0.58 and 1.57 ± 0.55 during the arterial phase, 1.87 ± 0.44 and 1.73 ± 0.39 during the portal venous phase, 1.63 ± 0.41 and 1.78 ± 0.39 during the equilibrium phase, and 1.10 ± 0.43 and 1.92 ± 0.50 during the hepatobiliary phase, respectively. The attenuation values in the tumor and liver parenchyma observed with enhanced CT were 40.60 ± 8.78 and 53.78 ± 7.37 precontrast, 172.66 ± 73.89 and 92.76 ± 17.92 during the arterial phase, 152.76 ± 35.73 and 120.12 ± 18.02 during the portal venous phase, and 108.74 ± 18.70 and 89.04 ± 7.25 during the equilibrium phase, respectively. Hemangiomas demonstrated peak enhancement during the arterial phase, and both the SIR with Gd-EOB-DTPA-enhanced MRI and the attenuation value with enhanced CT decreased with time. The SIR of hemangiomas was lower than that of liver parenchyma during the equilibrium and hepatobiliary phases on Gd-EOB-DTPA-enhanced MRI. However, the attenuation of hemangiomas after contrast injection was higher than that of liver parenchyma during all phases of enhanced CT. CONCLUSION:Prolonged enhancement during the equilibrium phase was observed less frequently on Gd-EOB-DTPA-enhanced MRI than enhanced CT, which may exacerbate differentiating between hemangiomas and malignant tumors.     

Endoscopic diagnosis of intraductal papillary mucinous neoplasm of the bile duct

Background/Purpose

Intraductal papillary mucinous neoplasm of the bile duct (IPMN-B) is considered an uncommon tumor. The purpose of this study was to evaluate the diagnostic utility of endoscopic cholangiography (ERC) with subsequent peroral cholangioscopy (POCS) and/or intraductal ultrasonography (IDUS) for this tumor.

Methods

From December 1991 to November 2006, a retrospective analysis was made of eight patients with IPMN-B. Their clinical features and the endoscopic diagnostic strategy for POCS and IDUS were reviewed.

Results

In all the patients, ERC failed to show papillary tumors, due to coexisting mucin or biliary sludge. POCS was carried out after ERC and it showed the presence and locations of papillary tumors in all patients, except for one with a tumor in the peripheral intrahepatic bile duct (B3). IDUS was performed in seven of the eight patients; in five of these patients, intraductal protruding tumors were clearly visualized, whereas flat tumors were not identified in the remaining two patients. In one of the eight patients, endoscopic nasobiliary drainage did not remove the huge amount of mucin. Hence, this patient required subsequent percutaneous biliary drainage. Six of the eight patients underwent surgical treatment; five patients underwent a hepatic resection with or without extrahepatic bile duct resection and one underwent a pancreaticoduodenectomy. Five of the six operated patients are still alive; one patient died of gastric cancer 90 months after the operation (mean follow-up period, 45.3 months). The two remaining patients, who were considered inoperable due to major medical comorbidities, died of liver failure and cholangitis 3 and 6 months, respectively, after stent placement.

Conclusion

ERC failed to delineate intraductal papillary tumors, due to coexisting mucin. The presence and location of papillary tumors were correctly diagnosed by both POCS and IDUS, but POCS may be better than IDUS to diagnose the extent of the tumor.     

Tumorigenesis and phenotypic characteristics of mucin-producing bile duct tumors: an immunohistochemical approach

Intraductal papillary neoplasm of the bile duct (IPNB) is characterized by exophytic proliferation of neoplastic epithelial cells with fibrovascular stalks in bile duct lumen, mucin hypersecretion, and considerable dilatation or multilocular changes of the affected bile ducts. A mucin-producing bile duct tumor is an IPNB with excessive mucin production and clinical symptoms. Herein, the phenotypes as well as the tumorigenesis and progression of IPNB are reviewed with immunohistochemical assistance. The tumors are subdivided into three phenotypes: pancreatobiliary, intestinal, and gastric. About half of IPNB cases are of the pancreatobiliary type, and the remaining half are of the intestinal type. Aberrant expression of CDX2 with MUC2 and CK20 is related to the development of intestinal metaplasia. Inactivation of P16INK4a and nuclear expression of β-catenin are related to the development of IPNB. Decreased expression of membranous β-catenin and E-cadherin and aberrant expression of MMP-7 and -9 and of MUC1 are related to invasion of IPNB with tubular adenocarcinoma, whereas MUC2 is involved in the invasion of IPNB with mucinous carcinoma. IPNB can be regarded as a counterpart of intraductal papillary mucinous neoplasm (IPMN) of the pancreas, particularly the main duct type. More comparative studies between IPNB and pancreatic IPMN are recommended for further analysis of these papillary neoplasms.     

Mucinous Cystic Neoplasm of the Liver or Intraductal Papillary Mucinous Neoplasm of the Bile Duct? A Case Report and a Review of Literature

Mucinous cystic neoplasm of the liver (MCN-L) and intraductal papillary mucinous neoplasm of the bile duct (IPMN-B) are diagnoses that were classified by the World Health Organization in 2010 as mucin-producing bile duct tumors of the hepatobiliary system. The preoperative differential diagnosis between these two entities is difficult; the presence of a communication with the bile duct is usually considered as a typical sign of IPMN-B. However, the presence of an ovarian-like stroma (OLS) has been established to define the diagnosis of MCN-L. We present the case of a 33-year-old woman with a rapid progression of a cystic tumor of the liver. In 2 years, the lesion increased from 27 to 64 mm and a dilation of the left hepatic duct appeared. Percutaneous transhepatic drainage with a biopsy was performed. No malignant cells were found on biopsy. Because of the rapid progression of the cystic tumor and unclear malignant potential, left hemihepatectomy was performed. Even though tumor masses were present in the biliary duct, on the basis of the presence of OLS, histology finally confirmed MCN-L with intermediate-grade intraepithelial dysplasia to high-grade intraepithelial dysplasia. The patient is currently under oncologic follow-up with no signs of recurrence of the disease. We present a rare case where MCN-L caused a dilation of the left hepatic duct, a sign that is usually a characteristic of IPMN-B.     

TWO CASES OF MUCIN‐PRODUCING CHOLANGIOCARCINOMA DIAGNOSED BY PERORAL CHOLANGIOSCOPY

Mucin‐producing cholangiocarcinoma, which excretes excessive amounts of mucin into the biliary tract and causes obstructive jaundice and cholangitis due to the mucin retention, is rare. In this paper, we report two cases of this disease, which were demonstrated by peroral cholangioscopy (POCS). The radiologic features of these tumors show the diffuse dilatation of the bile ducts demonstrated by computed tomography (CT) and ultrasonography (US), the amorphous filling defects in the dilated bile ducts revealed by cholangiography. Their endoscopic features are mucin flowing out from the papilla of Vater during endoscopic retrograde cholangiography (ERC), and the papillary tumor with contiguous superficial spread in the bile ducts observed by cholangioscopy, although removal of mucin in the biliary tract is sometimes necessary before cholangioscopy in order to examine the lesion sufficiently. According to the previous reports, prognosis after curative resection of these tumors is better than that of ordinary type of cholangiocarcinoma. Therefore, it is important to examine the tumor extension in the bile ducts by cholangioscopy, although a selection of route inserting cholangioscope is controversial.     

Left hepatic trisegmentectomy for intraductal papillary cholangiocarcinoma: report of a case

We present a rare case of intraductal papillary cholangiocarcinoma in a 69 year-old man which was treated with left hepatic trisegmentectomy. The hepatic bile ducts were dilated by intraductal masses, which had extended into the intrahepatic bile ducts without involvement of the posterior inferior segmental duct (B6). The patient underwent left hepatic trisegmentectomy with hilar duct resection. The tumors in the posterior superior segmental duct (B7) were resected and biliary reconstruction was performed with a jejunal loop. Post-operative recovery was good, and the patient survived for 7 months after surgery.     

Clinicopathological features of "intraductal papillary neoplasm of the bile duct" and patient outcome after surgical resection

BACKGROUND/AIMS: Intraductal papillary neoplasm of the bile duct (IPNB) represents a biliary papillary tumor mainly growing in the bile duct lumen resembling intraductal papillary mucin-producing neoplasm of the pancreas. However, its clinical spectrum and characteristics have not been fully evaluated. METHODOLOGY: To define the clinicopathologic characteristics and prognosis of IPNB patients, 6 cases of IPNB who underwent surgical resection are presented. RESULTS: Patients were 3 males and 3 females, aged between 47 and 79 years. Five patients had histories of hepatobiliary disease. Imagery showed cystic or diffuse dilatation of the bile ducts. Tumor markers were not valuable for diagnosis. All patients underwent hemihepatectomy with or without resection of the caudate lobe or extrahepatic bile duct. Examination showed polypoid tumors in 5 cases though 1 case had no evident tumor. Mucin was observed in 3 cases. Five cases were well-differentiated adenocarcinoma and 1 had poorly differentiated adenocarcinoma. Vascular invasion was rare and lymph node metastasis was not observed. In-situ spread of carcinoma was seen along biliary mucosa in 3 cases. Five cases survived without tumor relapse for long periods but 1 died of tumor recurrence at 31 months. CONCLUSIONS: Complete resection of IPNB based on accurate preoperative assessment of tumor extension provides a good prognosis.     

MRI对胰腺囊性肿瘤的诊断价值

目的探讨MRI对胰腺囊性肿瘤的诊断价值。方法回顾分析23例经手术病理证实的胰腺囊性肿瘤资料,总结其影像表现。结果黏液性囊性肿瘤10例,囊性肿块较大,肿块平均直径超过10 cm,由较厚的纤维壁分隔成多房囊肿,外壁光滑,边界清楚。浆液性囊腺瘤6例,病灶较小,囊内有分隔而呈放射状排列,中心瘢痕为其特征性表现。胰腺囊性转移瘤3例,均有肿瘤病史,表现不典型,需结合肿瘤病史定性。胰胚细胞瘤2例,幼儿发病,肿块巨大,肿瘤坏死囊变,形成假-假性囊肿。胰腺乳头状囊实性肿瘤1例,表现为边界清楚的囊实性肿块,囊壁上有壁结节。胰腺毛细血管瘤1例,表现与浆液性囊腺瘤相似,难以术前诊断。结论MRI对胰腺囊性肿瘤具有高度敏感性,不同病变有一定的特征性表现, 对术前定性极有价值。     

Precancerous lesions of the biliary tree

The neoplasms of the biliary tree include the carcinomas of the intra- and extrahepatic bile ducts, the gallbladder and the ampulla. Two types of precancerous lesions precede these adenocarcinomas: the flat and non-tumour forming type that is called biliary intraepithelial neoplasia, and the papillary and tumour-forming type that has been named intraductal papillary neoplasm of the bile duct. Rarely also biliary mucinous cystic neoplasm can give rise to invasive biliary adenocarcinomas. This review discusses the pathological, molecular, epidemiological, clinical and prognostic features of the precancerous biliary lesions, separated according to their origin in the bile ducts, the ampulla and the gall bladder.     

Assessment of Gd-EOB-DTPA-enhanced MRI for HCC and dysplastic nodules and comparison of detection sensitivity versus MDCT

Background

We aimed to evaluate gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) for the detection of hepatocellular carcinomas (HCCs) and dysplastic nodules (DNs) compared with dynamic multi-detector row computed tomography (MDCT), and to discriminate between HCCs and DNs.

Methods

Eighty-six nodules diagnosed as HCC or DNs were retrospectively investigated. Gd-EOB-DTPA-enhanced MRI and dynamic MDCT were compared with respect to their diagnostic ability for hypervascular HCCs and detection sensitivity for hypovascular tumors. The ability of hepatobiliary images of Gd-EOB-DTPA-enhanced MRI to discriminate between these nodules was assessed. We also calculated the EOB enhancement ratio of the tumors.

Results

For hypervascular HCCs, the diagnostic ability of Gd-EOB-DTPA-enhanced MRI was significantly higher than that of MDCT for tumors less than 2?cm (p?=?0.048). There was no difference in the detection of hypervascular HCCs between hepatobiliary phase images of Gd-EOB-DTPA-enhanced MRI (43/45: 96%) and dynamic MDCT (40/45: 89%), whereas the detection sensitivity of hypovascular tumors by Gd-EOB-DTPA-enhanced MRI was significantly higher than that by dynamic MDCT (39/41: 95% vs. 25/41: 61%, p?=?0.001). EOB enhancement ratios were decreased in parallel with the degree of differentiation in DNs and HCCs, although there was no difference between DNs and hypovascular well-differentiated HCCs.

Conclusion

The diagnostic ability of Gd-EOB-DTPA-enhanced MRI for hypervascular HCCs less than 2?cm was significantly higher than that of MDCT. For hypovascular tumors, the detection sensitivity of hepatobiliary phase images of Gd-EOB-DTPA-enhanced MRI was significantly higher than that of dynamic Gd-EOB-DTPA-enhanced MRI and dynamic MDCT. It was difficult to distinguish between DNs and hypovascular well-differentiated HCCs based on the EOB enhancement ratio.     

Intraductal papillary mucinous tumors and mucinous cystic tumors of the pancreas: imaging

Most cystic lesions of the pancreas are nonneoplastic and inflammatory in nature. However, approximately 5%–15% of cystic pancreatic masses may be neoplastic. Among the cystic neoplasms are the mucin-producing tumors, both the intraductal papillary mucinous neoplasms and the mucinous cystic neoplasms. Their imaging features on contrast-enhanced computed tomography (CT) and magnetic resonance imaging (MRI) can assist in the differentiation of these lesions. The imaging findings of both intraductal papillary mucinous neoplasm and mucinous cystic neoplasm are reviewed with attention to CT and MRI.     

Intraductal oncocytic papillary neoplasm of the bile duct: the first case of peribiliary gland origin

We report herein the first case of intraductal oncocytic papillary neoplasm of the bile duct arising from a peribiliary gland of the left hepatic duct. The patient was a 63-year-old Japanese man. Radiological and cholangioscopic examinations revealed intraductal tumor of the left hepatic duct. After pathological diagnosis of adenocarcinoma by cholangioscopic biopsy, a surgical hepatobiliary resection was performed. Pathological examination revealed papillary tumor in the left hepatic duct. Histologically, the tumor was identified as papillary neoplasm comprising oncocytic cells and delicate fibrovascular cores. Interestingly, this tumor originated from the cystic space in the bile duct wall. This cystic space was histologically identified as a cystically dilated peribiliary gland. Carcinoma in situ was observed in this cystic peribiliary gland at the bottom of the tumor, but not on any areas of biliary epithelium. This case suggests that intraductal papillary neoplasm can arise from both biliary epithelium and peribiliary glands.     

Laparoscopic resection of synchronous intraductal papillary mucinous neoplasms: A case report

We describe herein a 68-year-old woman who was diagnosed with a quite rare entity of intraductal papillary mucinous neoplasms (IPMNs) occurring simultaneously in the left lateral lobe of liver and the tail of pancreas. Abdominal computed tomography and magnetic resonance cholangiopancreatography showed a cystic dilatation of the pancreatic duct in the pancreatic tail, which suggested an IPMN, and multiple intrahepatic duct stones in the left lateral lobe. The patient underwent a laparoscopic left lateral hepatolobectomy and spleen-preserving distal pancreatectomy. Intra-operative finding of massive mucin in the dilated bile duct implied an intraductal mucinous tumor in the liver. The diagnosis of synchronous IPMNs in the liver and pancreas was confirmed by pathological examination. The patient was followed up for 6 mo without signs of recurrence. Although several cases of IPMN of liver without any pancreatic association have been reported, the simultaneous occurrence of IPMNs in the liver and pancreas is very rare. To the best of our knowledge, it is the first reported case treated by laparoscopic resection.     

A statement by the Japan‐Korea expert pathologists for future clinicopathological and molecular analyses toward consensus building of intraductal papillary neoplasm of the bile duct through several opinions at the present stage

Intraductal papillary neoplasm of bile duct (IPNB) was described as a preinvasive neoplastic lesion of the biliary tract in the 2010 World Health Organization (WHO) classification. Although a number of studies have since been conducted on IPNBs, controversy remains, particularly regarding the standardization of its definition. Meetings by Japanese and Korean expert pathologists were held twice to resolve the pathological diagnostic aspects of IPNB. Through round‐table discussions and histological reviews, we reached the common understanding that IPNBs diagnosed according to the criteria of WHO 2010 are characterized by intraductal predominant papillary or villous biliary neoplasms covering delicate fibrovascular stalks and are classified into two types pathologically. One type (type 1 IPNB) is histologically similar to intraductal papillary mucinous neoplasms of pancreas, and typically develops in the intrahepatic bile ducts, while the other (type 2 IPNB) has a more complex histological architecture with irregular papillary branching or with foci of solid‐tubular components and typically involves the extrahepatic bile ducts. This report states the diagnostic pathologic features of IPNB proposed by WHO 2010. Since currently, the concept of IPNB is still confusing, the proposed diagnostic pathologic features stated here will be of use for future clinicopathological and molecular analyses toward consensus building of IPNB.     

Recurrent cholangitis as the first manifestation of an intraductal papillary mucinous tumor of the pancreas

Intraductal papillary mucinous tumor is a rare pancreatic tumor originating from the epithelium of the pancreatic duct and exhibiting papillary proliferation of tall columnar epithelial cells. The usual clinical presentation is recurrent episodes of pancreatitis due to hypersecretion of mucin and obstruction of a markedly dilated pancreatic duct. We describe a 74-year-old man who presented recurrent attacks of cholangitis, due to a common bile duct obstruction from thick pancreatic mucus reflux, as the first manifestation of intraductal papillary mucinous tumor.     

Endoscopic ultrasound characteristics of mucinous cystic neoplasms of the pancreas

OBJECTIVE: Mucinous cystic neoplasms of the pancreas have a more favorable prognosis than ductal adenocarcinoma. Management of a subgroup, intraductal papillary-mucinous neoplasms, is controversial. Endoscopic ultrasound (EUS) with fine-needle aspiration biopsy may emerge as the imaging modality of choice. There are few studies describing the EUS features of these tumors. METHODS: A total of 35 consecutive cases of cystic tumors of the pancreas with an established pathological diagnosis were analyzed for characteristic EUS features. RESULTS: Mucinous cystadenocarcinomas (n = 14) were more likely to be characterized by hypoechoic cystic/solid mass or complex cyst and were frequently associated with a dilated main pancreatic duct. Benign mucinous duct ectasia (n = 6) were characterized by a dilated main pancreatic duct in conjunction with hyperechoic thickening of the duct wall. The two cases of intraductal mucinous hyperplasia additionally showed a hypoechoic mass. Intraductal papillary carcinoma (n = 11) had features in common with mucinous cystadenocarcinoma but also had echogenic foci in the mass and intraductal hyperechoic lesions. The two cases of microcystic cystadenoma showed either a mixed hypoechoic solid/cystic mass or a complex cyst without the additional features seen in mucinous cystadenocarcinoma. CONCLUSIONS: EUS features seem to exist that may help to differentiate cystic neoplasms from adenocarcinoma of the pancreas and, thus, to establish the preoperative diagnosis of cystic tumors of the pancreas.