Small invasive ductal carcinoma of the pancreas distinct from branch duct intraductal papillary mucinous neoplasm

Endoscopic ultrasonography (EUS) is a highly sensitive diagnostic method for the detection of small pancreatic carcinomas.Recently, there have been some reports describing the utility of contrast-enhanced harmonic EUS (CEH-EUS) which uses sonographic contrast agent for differentiation of a pancreatic mass.This report describes a case of small adenocarcinoma of the pancreas distinct from branch duct intraductal papillary mucinous neoplasm (IPMN) in which investigation by EUS took place every 6 mo and diagnosis was made accurately by additional CEH-EUS during the followup of the branch duct IPMN.A 68-year-old female was admitted to our hospital because of a branch duct IPMN in the pancreatic body.She had been followedup by EUS every 6 mo.However, after 2 years EUS demonstrated a low echoic area distinct from the branch duct IPMN which was vaguely discernible by EUS, and accurate sizing and differential diagnosis were considered difficult on the EUS imaging.CHEUS with Sonazoid revealed a hypovascular tumor and we suspected small pancreatic carcinoma.The histopathological diagnosis was adenocarcinoma (10 mm) in the pancreatic tail, distinct from the branch duct IPMN of the pancreatic body.EUS and CEH-EUS may play an important role in the correct diagnosis of small pancreatic tumors, including synchronous and metachronous occurrence of IPMN and ductal adenocarcinoma of the pancreas.     

A case of minimal invasive carcinoma from intraductal papillary mucinous neoplasm with invasive ductal carcinoma of the pancreas]

A 69-year-old man was referred to our hospital for epigastralgia. He was found to have elevation of serum amylase and CA19-9. Ultrasonography, abdominal CT, MRCP, ERCP and EUS showed the cystic lesion and a possibility of an other tumor. There was a stenosis of the main pancreatic duct (MPD) at the pancreas head and dilatation of the MPD from the body to the tail. Intraductal papillary mucinous neoplasm (IPMN) of the branch pancreatic duct was diagnosed, and there was a likelihood of ductal carcinoma of the pancreas. We therefore performed pancreatoduodenectomy. Pathological finding showed invasive carcinoma from an intraductal papillary mucinous neoplasm with invasive ductal carcinoma of the pancreas.     

Experience of limited pancreatic head resection for management of branch duct intraductal papillary mucinous neoplasm in a single center

AIM： To share our surgical experience and the outcome of limited pancreatic head resection for the management of branch duct intraductal papillary mucinous neoplasm （IPMN）.
METHODS： Between May 2005 and February 2008, nine limited pancreatic head resections （LPHR） were performed for IPMN of the pancreatic head. We reviewed the nine patients, retrospectively.
RESULTS： Tumor was located in the uncinate process of the pancreas in all nine patients. Three patients had stents inserted in the main pancreatic duct due to inju- ry. The mean size of tumor was 28.4 mm. Postoperative complications were found in five patients： 3 pancreatic leakages, a pancreatitis, and a duodenal stricture. Pancreatic leakages were improved by external drainage. No perioperative mortality was observed and all patients are recorded alive during the mean follow-up period of 17.2 mo.
CONCLUSION： In selected patients after careful evaluation, LPHR can be used for the treatment of branch duct type IPMN. In order to avoid pancreatic ductal injury, pre- and intra-operative definite localization and careful operative techniques are required.     

Coexisting Type 1 Autoimmune Pancreatitis and Mixed-type Intraductal Papillary Mucinous Neoplasm

An 84-year-old man was referred to our hospital for a cystic lesion of the pancreatic head, swelling of the pancreatic tail and hilar biliary stricture, resulting in elevated liver enzyme levels. We suspected branch duct-type intraductal papillary mucinous neoplasm (IPMN) and type I autoimmune pancreatitis (AIP) associated with sclerosing cholangitis because of the high serum IgG4 levels. The main pancreatic duct on the tail side of the AIP lesion was moderately dilated. Although the biliary stricture and pancreatic swelling improved after prednisolone treatment, the pancreatic enzyme levels increased rapidly. The entire main pancreatic duct exhibited remarkable dilatation, which led to the diagnosis of mixed-type IPMN. The clinical characteristics of IPMN in the main pancreatic duct appear to have been initially masked by AIP.     

Multifocal intraductal papillary mucinous neoplasm of the pancreas-A case report

Cystic neoplasms of the pancreas are relatively rare, comprising 10 percent of pancreatic cysts and only 1 percent of pancreatic cancers. Cystic neoplasms include mucinous cystic neoplasms, serous cystadenomas, papillary cystic tumors, cystic islet cell tumors and intraductal papillary mucinous neoplasms of the pancreas （IPMNs）. IPMN was first described in 1982. It has been most commonly described in 60 to 70 years old males, and represents a relatively ＂new＂ but increasingly recognized disease. The improvement and widespread use of modern imaging equipments and heightened awareness of physicians contribute to the increasing incidence of IPMN. The majority of IPMNs are located in the pancreatic head （75%） while the rest involves the body/tail regions. Multifocal IPMNs have been hypothesized, but the true presence of multifocality is unknown. Here we present a 72-year- old male diagnosed with IPMN （carcinoma in situ） in the pancreatic head and a branch duct type IPMN （duct atypia） in the pancreatic body and tail. The patient underwent a Whipple intervention and a distal pancreatectomy. A three-year disease-free survival has been observed so far.     

Invasive carcinoma derived from intraductal papillary mucinous carcinoma of the pancreas

BACKGROUND/AIMS: Most patients with intraductal papillary mucinous tumors of the pancreas have a favorable prognosis after surgical treatment. However, recurrent disease frequently occurs in patients with invasive carcinoma derived from intraductal papillary mucinous carcinoma. The objective of this study was to clarify the clinicopathological features of invasive carcinoma derived from intraductal papillary mucinous carcinoma. METHODOLOGY: We performed a retrospective review of the 29 patients with intraductal papillary mucinous tumor including 10 patients with invasive carcinoma who underwent pancreatic resection between June 1995 and December 2001 at the National Cancer Center Hospital East. RESULTS: Of 10 patients with invasive carcinoma derived from intraductal papillary mucinous carcinoma, 7 patients had lymph node involvement and 8 patients had retroperitoneal invasion. The overall 1-, 2-, 4-year actuarial survival rate for invasive carcinoma derived from intraductal papillary mucinous carcinoma was 39%, 26%, 13%. Recurrence occurred as liver metastasis in 3 patients, carcinomatous peritonitis in 3, local recurrence in 3, and lung metastasis in 1. All patients with adenoma, non-invasive carcinoma, and minimally invasive carcinoma are alive without recurrent disease after pancreatic resection. CONCLUSIONS: Patients with invasive carcinoma derived from intraductal papillary mucinous carcinoma had a worse prognosis. Margin-negative pancreatic resection is essential for treating this disease.     

Inferior head resection of the pancreas for intraductal papillary mucinous neoplasms

Background

Previous reports have suggested that patients with intraductal papillary mucinous neoplasm (IPMN) have a favorable prognosis after surgical resection. Thus, a variety of types of partial pancreatic resections have been advocated for treating these low-grade malignant tumors. However, the surgical outcome of IPMN after such limited pancreatectomy has not been fully clarified.

Methods

We performed a retrospective review of the clinicopathologic features and surgical outcome in 15 patients who underwent inferior head resection for IPMN at the Chiba University Hospital and National Cancer Center Hospital East between July 1994 and January 2007.

Results

There were 13 patients with noninvasive IPMNs (10 adenomas and 3 noninvasive carcinomas) and 2 patients with minimally invasive intraductal papillary mucinous carcinoma (minimally invasive IPMN). Complete tumor removal (R0 resection) was performed in four patients (80%) with intraductal papillary mucinous carcinoma. Subsequent pancreatoduodenectomy was performed in one patient because of noninvasive carcinoma with multiple mucous lakes in the pancreatic parenchyma. Values for N-benzoyl-l-tyrosyl-p-aminobenzoic acid excretion test results before (n?=?13) and after (n?=?13) the operation were 70.7 and 66.1, showing no significant difference. The 2-h glucose levels in the 75?g oral glucose tolerance test before (n?=?13) and after (n?=?13) the operation were 133 and 146?mg/dl, respectively, showing no significant difference. Pancreatic fistula occurred in 7 (47%) patients. Overall morbidity and mortality rates were 67 and 0%, respectively. The overall 1-, 3-, 5-, and 10-year survival rates for the 15 patients were 100, 79, 79, and 71%, respectively. The 1-, 3-, 5-, and 10-year survival rates for patients with noninvasive IPMN (n?=?13) and those with minimally invasive IPMN (n?=?2) were 100, 92, 92, and 83%; and 100, 0, 0, and 0%, respectively. There was a significant difference in survival between patients with noninvasive IPMN and those with minimally invasive IPMN (p?=?0.0005). No patient with noninvasive IPMN developed recurrent disease. One patient with minimally invasive IPMN died of recurrent peritoneal dissemination 18?months after margin-positive R1 resection. Two patients died of pancreatic ductal adenocarcinoma, 30 and 78?months after inferior head resection.

Conclusions

Pancreatic endocrine and exocrine function was well preserved after inferior head resection. Pancreatic fistula occurred more frequently after inferior head resection than with conventional pancreatoduodenectomy. Patients with noninvasive IPMN had favorable survivals after this procedure. However, one patient with minimally invasive IPMN with margin-positive R1 resection died of recurrent disease. Thus, margin-negative R0 resection should be performed for IPMN.     

Intraductal papillary mucinous carcinoma with atypical manifestations： Report of two cases

Intraductal papillary mucinous neoplasms(IPMNs)are a well-characterized group of mucin-producing cystic neoplasms of the clear malignant potential type.We report here two cases of intraductal papillary mucinous carcinoma(IPMC)with atypical manifestations.In one case,we discussed a pseudomyxoma peritonei caused by a ruptured IPMC.In the other case we discussed the fistulization of IPMC into the stomach and duodenum.These two cases suggest that IPMN can either spontaneously rupture causing mucinous materials to spill into the free abdominal cavity or directly invade adjacent organs resulting in fistula development.     

胰腺癌前病变诊断和治疗

目的 通过对7例胰腺癌前病变患者的临床诊断和治疗分析,探讨此类疾病诊断方法的应用及治疗策略.方法 收集2006年1月-2007年12月92例手术治疗胰腺肿瘤中有癌前病变的7例患者,其中黏液囊腺瘤(MCN)1例、导管内乳头状黏液瘤(IPMN)2例、胰腺内分泌肿瘤1例、胰腺上皮内瘤变(PanIN)Ⅰ级、Ⅱ级及Ⅲ级各1例.采用免疫荧光分析法测定患者血清CA19-9.7例上腹部均行超声和螺旋CT检查;1例行超声内镜检查及穿刺;2例行逆行胰胆管造影检查.结果 胰腺癌前病变临床表现不典型,影像学检查常无实质性肿块,但PanIN可伴有胰管扩张、狭窄;IPMN在胰头处可表现为囊性扩张的胰管;囊腺瘤等在胰体尾处可表现为单个孤立的囊肿.肿瘤指标CA19-9在此类疾病中可轻度增高.但对诊断作用有限.手术切除可治愈,并可防止肿瘤的进一步癌变.结论 对疑为胰腺癌前病变患者需积极选用多种影像学方法进行诊断,并予以积极的手术探查及切除.     

Localized type 1 autoimmune pancreatitis superimposed upon preexisting intraductal papillary mucinous neoplasms

A 70-year-old woman was found to have 2 cystic lesions in the head of the pancreas on abdominal ultrasonography during a routine medical examination.Endoscopic ultrasonography(EUS)and magnetic resonance cholangiopancreatography showed multilocular cysts in the head of the pancreas without dilation of the main pancreatic duct.The patient was followed-up semiannually with imaging studies for suspected branch duct-type intraductal papillary mucinous neoplasm(IPMN).At 3 years after initial presentation,hypoechoic lesions were observed around each pancreatic cyst by EUS.Diffusion-weighted imaging showed high-intensity regions corresponding to these lesions.Therefore,a diagnosis of invasive carcinoma derived from IPMN could not be excluded,and subtotal stomach-preserving pancreaticoduodenectomy was performed.The macroscopic examination of the surgical specimen showed whitish solid masses in the head of the pancreas,with multilocular cysts within each mass.Microscopically,each solid mass consisted of inflammatory cells such as lymphocytes and plasma cells.Furthermore,immunochemical staining revealed immunoglobulin G4-positive cells,and many obliterating phlebitides were observed.The cysts consisted of mucus-producing epithelial cells and showed a papillary growth pattern.Based on these findings,we diagnosed multiple localized type 1 autoimmune pancreatitis occurring only in the vicinity of the branch ducttype IPMN.     

Recurrent invasive intraductal papillary mucinous carcinoma of the pancreas mimicking pott disease: review of the literature

Specific information regarding intraductal papillary mucinous neoplasm (IPMN) recurrence is limited because most series are small and the follow-up interval is short. We report an unusual case of cancer recurrence in an 86-year-old woman who had undergone a pancreaticoduodenectomy for a large IPMN in the head of the pancreas. Final pathological evaluation of the resected pancreas found a component of in situ and invasive ductal adenocarcinoma without lymph node involvement. The patient did not receive postoperative chemotherapy and was monitored with transaxial imaging at regular intervals. Nine years later, the patient developed a retroperitoneal psoas abscess that was misdiagnosed as tuberculous spondylitis (Pott disease) but was proven to be recurrent mucinous adenocarcinoma of pancreatic origin. In our review of published reports in patients who underwent resection of IPMN, we found a combined mean recurrence rate of approximately 20%.     

Clinical fate of branch duct and mixed forms of intraductal papillary mucinous neoplasia of the pancreas

Aims:  The aim of the present study was to assess the clinical fate of, and to gain new insights into, branch duct and mixed (predominantly main duct type) forms of intraductal papillary mucinous neoplasia of the pancreas (IPMN).
Methods:  During a 17-year period, 99 successive IPMN patients (52 men, 47 women; mean age, 64 years) were included and divided into two groups for further comparison: one group had branch duct IPMN, whereas the other had mixed IPMN.
Results:  Patients from the mixed IPMN group ( n  = 52) displayed a greater rate of symptoms (83% vs 55%, P  = 0.004), pancreatic resection (67% vs 38%, P  = 0.007), malignancy (35% vs 13%, P  = 0.017) and death (15% vs 4%, P  = 0.09) than those from the branch duct IPMN group. A 38-month follow up of non-operated, symptom-free patients confirmed that more than 85% of branch duct IPMN patients were asymptomatic without evidence of malignancy. Borderline lesions and carcinoma are found in up to 50% of symptomatic resected branch duct IPMN cases.
Conclusion:  Patients with the mixed form of IPMN as well as with symptomatic branch duct IPMN should require pancreatic resection because of symptoms and the risk for malignancy. In silent branch duct IPMN without radiological signs of malignancy, a non-operative watch-and-wait strategy can be discussed.     

Invasive carcinoma of the pancreas derived from intraductal papillary adenocarcinoma without mucin hypersecretion but with changes in the pancreatic duct on pancreatography

We present a case of invasive carcinoma of the pancreas derived from intraductal papillary adenocarcinoma without mucin hypersecretion in a 65‐year‐old man with a 45‐year history of alcohol abuse and a 2‐year follow‐up of chronic pancreatitis. Two years previously, in May 1998, he was admitted for investigation of abdominal pain. Computed tomography (CT) showed diffuse dilation of the main pancreatic duct with atrophy of the pancreatic parenchyma. Endoscopic retrograde pancreatography (ERP) showed a diffusely dilated main pancreatic duct with irregular side branches in the head of the pancreas. Chronic alcoholic pancreatitis was diagnosed on the basis of the pancreatography findings. The patient was readmitted for investigation of progressive weight loss in August 2000. Serum CA19‐9 levels were markedly elevated (750U/ml) and CT showed enlargement of the head and body of the pancreas. ERP showed irregularity of the main pancreatic duct in the head of the pancreas, and the distal main pancreatic duct (which was dilated on initial ERP examination) was interrupted in the body of the pancreas. Suspected pancreatic carcinoma was diagnosed, and pylorus‐preserving pancreatoduodenectomy was performed. Frozen section examination of the cut end of the pancreas revealed ductal carcinoma, and total pancreatoduodenectomy with portal vein resection was performed. Histologically, the resected tumor was diagnosed as an invasive carcinoma derived from intraductal papillary adenocarcinoma without mucin hypersecretion. We recommend observing changes in the pancreatic duct on pancreatography to diagnose invasive carcinoma of the pancreas derived from intraductal papillary adenocarcinoma in a resectable state.     

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.     

Virtual CO2 MDCT pancreatography: a new feasible technique for minimally invasive pancreatectomy in intraductal papillary mucinous neoplasms

BACKGROUND/AIMS: Less invasive pancreatic head resection, such as duodenum-preserving pancreatic head resection (DPPHR) has been introduced for the treatment of pancreatoduodenal lesions, especially for benign conditions, for reducing surgical stress and maintaining exocrine and endocrine function of the residual pancreas in consideration of postoperative quality of life (QOL). METHODOLOGY: We investigated the feasibility of a new technique employing three-dimensional (3D) virtual pancreatography using multi-detector CT (MDCT) with carbon dioxide (CO2) gas as a negative contrast agent for detection of intraductal papillary mucinous neoplasm (IPMN) of the pancreas requiring minimally invasive surgery. Branch IPMN is subjected in this study. RESULTS: Contrast-enhanced MDCT scan of the abdomen diagnosed 4- to 20-mm multilocular septated cysts in the head-uncinate process of the pancreas. Endoscopic retrograde pancreatography (ERP) showed multiple cystic lesions in the head-uncinate process with mild dilatation in the remaining pancreatic duct. For localizing diagnosis of these small and multiple pancreatic cysts, we placed an endoscopic pancreatic stent (EPS), and MDCT with injection of CO2 via EPS was examined for the virtual CO2 pancreatography, consisting of OsiriX software system employing 3D virtual anatomic reconstruction with CO2 gas as a negative contrast agent. Virtual CO2 MDCT pancreatography demonstrated that all cystic lesions of the pancreas were contained within the area of the head-uncinate process of the pancreas. We performed DPPHR, and surgical margin of the patient's remnant pancreas was determined as non-malignant by intraoperative histology. There was no residual pancreatic cyst and tumor after surgery. The resected tumor was diagnosed as branch duct type intraductal papillary mucinous adenocarcinoma. According to our minimally invasive DPPHR obtained by virtual CO2 pancreatography, the pancreatic endocrine and exocrine functions of this patient were maintained at almost the same levels as those in his preoperative status. With respect to preservation of the endocrine and exocrine functions of the pancreas, DPPHR is a highly effective surgical procedure due to limited surgical resection. CONCLUSIONS: Our new technique of virtual CO2 MDCT pancreatography is a feasible procedure for preservation of the remnant pancreatic function. This is the first report of virtual CO2 pancreatography providing minimally invasive pancreatic surgery.     

胰腺导管内乳头状黏液瘤

胰腺导管内乳头状黏液瘤（IPMN）是由胰腺导管内产生黏液的上皮细胞呈乳头状增殖形成的肿瘤。与经典的胰腺癌相比,IPMN具有低度恶性、生长缓慢、少有侵犯周围组织、淋巴结转移率和再发率低的特点。IPMN根据肿瘤累及的部位可分为主胰管型、分支胰管型和混合型,病理组织特征涵盖从单纯腺瘤到浸润癌等多个亚型,临床表现多样,多种影像学检查手段可显示弥漫性或节段性扩张的主胰管和囊状扩张的分支胰管,ERCP经扩大的乳头获取黏液和胰液,取胰腺导管内皮组织和壁结节供活检均有助于诊断。IPMN确诊后应积极手术,手术切除率高,术后5年生存率高于一般的胰腺癌。本文就其临床表现、分类、病理特征、影像学诊断和治疗等方面做一综述。     

Pseudomyxoma peritonei arising from intraductal papillary neoplasm after surgical pancreatectomy: report of 2 cases and review of the literature

We report 2 cases of pseudomyxoma peritonei (PMP) combined with an intraductal papillary mucinous neoplasm (IPMN) and a review of the literature. In both cases, PMP emerged after surgical resection of the IPMN. In one case, neoplastic foci were present in the surgical margin and PMP was found 1 year after the initial resection, while PMP emerged 5 years after surgical resection in the other case. Including these 2 cases, 8 cases of PMP arising from IPMN have been reported. This condition occurs more frequently in males (7 males, 1 female), while the age at diagnosis ranges from 49 to 82 years, with a mean of 63.3 years. IPMNs occur more commonly in the tail of the pancreas (62.5%). Two different patterns regarding the mechanism of PMP arising from IPMN have been indicated; a rupture of the pancreatic duct, after which the neoplasm spreads through the fistula into the peritoneal cavity, and post-surgical development of PMP after insufficient surgical treatment for an IPMN. Our findings indicate that attention must be given to avoid mucous leakage and obtain a negative surgical margin during surgical treatment of an IPMN.     

A case of intraductal papillary mucinous neoplasm of the pancreas arising from pancreas divisum without ventral pancreatic duct of Wirsung]

Most reported cases of intraductal papillary mucinous neoplasms (IPMNs) originate from Wirsung's duct or their branches. IPMNs arising from Santorini's duct and its branches have rarely been reported. Eight cases of IPMN arising from Santorini's duct have been published worldwide. However, these cases are associated with incomplete type of pancreas divisum. Recently, one report of IPMN with complete absence of Wirsung's duct has been reported. This patient was a 57-year-old woman who was admitted to the hospital due to progressive jaundice. On endoscopic retrograde cholangiopancreatography, there was a severely bulging ampulla of Vater and patulous minor papilla draining mucinous material and a cystic lesion communicating with the dilated Santorini's duct without any communication with Wirsung's duct. A pancreaticoduodenectomy was performed and the pathologic examination of resected specimen showed no evidence of Wirsung's duct, but an IPMN arising from Santorini's duct with peripancreatic lymph node metastasis. Herein, we report a case of invasive IPMN arising from pancreatic head without ventral pancreatic duct with a review of the relevant literatures.     

p53 protein expression in intraductal papillary mucinous tumors (IPMT) of the pancreas as an indicator of tumor malignancy

BACKGROUND/AIMS: Intraductal papillary mucinous tumors, as a cystic disease in the pancreas, clinically has a more indolent and favorable course than invasive ductal pancreas carcinoma. However, some cases of intraductal papillary mucinous tumors show invasive and rapid progression like ductal pancreas carcinoma and the prognosis of such patients is sometimes poor. In the current study, we carried out immunohistochemical staining of intraductal papillary mucinous tumor tissues for p53 and investigated whether positive staining indicates tumor malignancies and has a prognostic value for intraductal papillary mucinous tumors. METHODOLOGY: Nineteen (19) patients who underwent pancreatic resection under the diagnosis of intraductal papillary mucinous tumors at the Chiba University Hospital between April 1992 and December 1996 were studied. We performed immunohistochemical staining of p53 as well as of PCNA, Ki-67 and Bcl-2 using their respective antibodies. Pathological findings revealed that 9 cases were intraductal papillary adenoma, 9 were intraductal papillary adenocarcinoma, and one was invasive ductal papillary adenocarcinoma. RESULTS: p53 expression could only be detected in the 1 case with invasive ductal papillary adenocarcinoma. Significant association could not be found between histological features and immunohistochemical staining of PCNA, Ki-67 and Bcl-2. CONCLUSIONS: p53 protein expression could be detected after progression to invasive type of intraductal papillary mucinous tumors. The present results demonstrate that p53 expression might be an indicator of invasive progression in intraductal papillary mucinous tumors, and might represent a surgical indicator of intraductal papillary mucinous tumors.     

Biliopancreatic fistula associated with intraductal papillary-mucinous pancreatic cancer: institutional experience and review of the literature

Intraductal papillary-mucinous tumour is clinicopathologically characterized by papillary growth and mucin production within the pancreatic duct system. The category includes a wide range of dysplasia, ranging from adenoma to carcinoma, the latter designated as intraductal papillary-mucinous cancer. In general, the tumor renders a favorable prognosis after complete resection. However, intraductal papillary-mucinous tumor with overt invasion outside the gland has been reported to have a poor prognosis, as is the case with the usual type of duct cell cancer of the pancreas. We experienced two cases of intraductal papillary-mucinous cancer with obstructive jaundice due to impaction of thick mucus protruding from the pancreas via a "spontaneous" biliopancreatic fistula. Preoperative examinations of both patients showed a large intraductal papillary-mucinous tumor in the head of the pancreas with fistula formation between the intrapancreatic portion of the common bile duct and the main pancreatic duct. Histopathological investigation of the two resected specimens suggested that the fistula may not have developed from invasion by papillary or tubular adenocarcinoma, but from compression and destruction of the intercalating tissues by abundant mucinous secretion. The first patient died of peritoneal carcinomatosis with clinicopathologic features of pseudomyxoma peritonei 6 years after surgery. The second patient is alive and has been well for 2 years postoperatively. Review of the world literature showed that half of the patients with intraductal papillary-mucinous cancer plus biliopancreatic fistula had no stromal invasion around the fistula, indicating that the fistula might have been caused by mechanical pressure. However, the other half of the cases did have stromal invasion around the fistula. Two-thirds of these cases, including our own patients, had foci of mucinous carcinoma in the stroma around the fistulization, implying that mucinous lakes in the stroma may have served as part of the "waterway" from the pancreatic duct to the bile duct, assisted by increased pressure by mucus production. Since intraductal papillary-mucinous cancer with biliopancreatic fistula has a comparatively favorable prognosis, surgical resection should be considered.