CLINICAL SIGNIFICANCE OF INTRADUCTAL ULTRASONOGRAPHY FOR DIAGNOSIS OF INTRADUCTAL PAPILLARY MUCINOUS NEOPLASM OF THE PANCREAS

Intraductal ultrasonography (IDUS) is useful for evaluating the horizontal spread along the main pancreatic duct in cases of intraductal papillary mucinous neoplasm (IPMN) of the pancreas, thus providing valuable information for the determination of the resection line at surgery. Differentiation between benign and malignant IPMN is also indispensable for management decisions. Measurement of the height of mural nodules by IDUS is expected to be useful for differential diagnosis of IPMN. Because IDUS cannot always demonstrate whole lesions, especially in branch duct IPMN, endoscopic ultrasonography plays a complementary role in such cases.     

Size of mural nodule as an indicator of surgery for branch duct intraductal papillary mucinous neoplasm of the pancreas during follow-up

Background

A mural nodule is a strong predictive factor for malignancy in branch duct intraductal papillary mucinous neoplasm (IPMN) of the pancreas, but the nodule size has hardly been considered. The aim of this study was to investigate whether a mural nodule of 10?mm was appropriate as an indicator of surgery for IPMN during follow-up.

Methods

The follow-up outcomes of 100 patients who had branch duct IPMN without mural nodules or who had branch duct IPMN with mural nodules of less than 9?mm in a tertiary care setting were investigated retrospectively. The patients underwent abdominal ultrasound (US) every 3?months and additional imaging examinations or cytologic examination of pancreatic juice when necessary. Surgery was recommended to them when a mural nodule developed or when a nodule enlarged and reached 10?mm.

Results

During an average follow-up period of 97?months, branch duct IPMNs developed mural nodules that reached 10?mm in 5 patients (0.62% per year). In one patient the IPMN was revealed to be non-invasive carcinoma by resection, 1 IPMN was shown to be malignant by further follow-up, and 3 were not resected because of refusal or the patient??s age. In 7 patients, mural nodules stayed within 9?mm. The remaining 88 patients lacked mural nodules in their branch duct IPMNs throughout the follow-up. The occurrence of invasive carcinoma around the IPMN was not indicated by imaging examinations in any patient. Univariate analysis showed that the size of the cyst at baseline significantly predicted the development of a mural nodule that reached 10?mm during follow-up (P?=?0.05).

Conclusions

A mural nodule of 10?mm is appropriate as an indicator of surgery in the follow-up of branch duct IPMN.     

Management of intraductal papillary mucinous neoplasm of the pancreas

Intraductal papillary mucinous neoplasm (IPMN) of the pancreas is a distinct entity characterized by papillary proliferations of mucin-producing epithelial cells with excessive mucus production and cystic dilatation of the pancreatic ducts. IPMNs have malignant potential and exhibit a broad histologic spectrum, ranging from adenoma to invasive carcinoma. IPMNs are classified into main duct and branch duct types, based on the site of tumor involvement. IPMN patients have a favorable prognosis if appropriately treated. The postoperative 5-year survival rate is nearly 100% for benign tumors and noninvasive carcinoma, and approximately 60% for invasive carcinoma. A main duct type IPMN should be resected. Surgical treatment is indicated for a branch duct IPMN with suspected malignancy (tumor diameter ≥ 30 mm, mural nodules, dilated main pancreatic duct, or positive cytology) or positive symptoms. Malignant IPMNs necessitate lymph node dissection (D1). IPMNs are associated with a high incidence of extrapancreatic malignancies and pancreatic ductal carcinoma.     

Management of intraductal papillary-mucinous neoplasm of the pancreas: treatment strategy based on morphologic classification

GOALS: The aim of this study was to examine and clarify the preoperative markers that are useful for differentiating between benign and malignant lesions of intraductal papillary-mucinous neoplasms (IPMN) of the pancreas, grouped according to morphologic classification. BACKGROUND: There are various stages of pathology in IPMN, ranging from benign to malignant lesions. Although the determination of appropriate treatment guidelines to deal with IPMN is a critical issue, no such guidelines have been established. PATIENTS AND METHODS: One hundred twenty cases of IPMN were classified morphologically into either main or branch duct types. We compared the morphologic classification with histopathologic diagnosis using indicators of malignancy detected by imaging such as main duct diameter, the number and diameter of cysts, and the presence or absence of mural nodules. We also examined the usefulness of pancreatic juice cytology and measurement of telomerase activity as indicators of malignancy. Finally, we performed a survival analysis on the basis of morphologic classification to determine prognosis of IPMN. RESULTS: Whereas a high incidence (64%) of malignant lesions was seen in main duct type IPMN, benign lesions were dominant (80.5%) in branch duct type IPMN. Survival analysis showed that the prognosis was significantly worse in main duct type than in branch duct type IPMN. The lesions were aggravated in all patients with main duct type who did not undergo resection, resulting in death due to progression of the pancreatic lesion. The incidence of mural nodules was a useful indicator in main duct type, whereas main duct diameter and incidence of mural nodules were useful indicators in branch duct type. Although pancreatic juice cytology showed a high accuracy rate with low sensitivity for determining malignancy, measurement of telomerase activity in this juice was very effective for differentiating between benign and malignant lesions. CONCLUSIONS: The incidence of malignant lesions was extremely high in main duct type IPMN, indicating that surgery is required in all these patients. However, to determine whether surgery is indicated in branch duct type IPMN it is necessary to obtain an appropriate image diagnosis focusing on main duct diameter and mural nodules and also to carry out cytology and measurement of telomerase activity in samples of pancreatic juice.     

Pancreatic juice cytology in IPMN of the pancreas.

BACKGROUND: Intraductal papillary-mucinous neoplasm (IPMN) of the pancreas is a disease ranging from adenoma to borderline (with moderate dysplasia) and further to carcinoma (noninvasive and invasive) and surgical strategy is different by the grades of dysplasia. METHODS: Preoperative pancreatic juice cytology in IPMN was reviewed in 71 patients with IPMN who underwent surgical resection. RESULTS: The IPMN was adenoma in 48 patients, borderline in 13 and carcinoma (invasive) in 10. The sensitivity of pancreatic juice cytology in malignant IPMN was 40% (4/10). In 4 patients with the 48 IPM adenomas, diagnosis of pancreatic juice cytology was class IV or V. One of the 4 cases was considered to be an overdiagnosis of cytology, but the other 3 cases were considered to be a consequence of accompanying carcinoma in situ (or PanIN-3) (2 patients) or invasive ductal adenocarcinoma (1 patient) apart from IPMN. Sensitivity of pancreatic juice cytology was higher in IPMN of the main duct type with mucin hypersecretion and with mural nodules. CONCLUSIONS: These findings suggest that pancreatic juice cytology in IPMN is useful especially in the main duct type with mucin hypersecretion and mural nodules. When the diagnosis of pancreatic juice cytology is malignant in otherwise benign-looking IPMNs, coexistence of pancreatic carcinoma should be suspected.     

Clinical aspects of intraductal papillary mucinous neoplasm of the pancreas

Intraductal papillary mucinous neoplasm (IPMN) is a spectrum of neoplasia in the pancreatic duct epithelium characterized by cystic dilation of the main and/or branch pancreatic duct. According to the site of involvement IPMNs are classified into three categories, i.e., main duct type, branch duct type, and combined type. Most branch duct IPMNs are benign, whereas the other two types are often malignant. A large size of branch duct IPMN and marked dilation of the main pancreatic duct indicate the presence of adenoma at least. The additional existence of large mural nodules increases the possibility of malignancy in all types. Of recent interest is the relatively high prevalence of synchronous and/or metachronous malignancy in various organs, including the pancreas. The prognosis is favorable after complete resection of benign and noninvasive malignant IPMNs. Malignant IPMNs acquiring aggressiveness after parenchymal invasion necessitate adequate lymph node dissection. On the other hand, asymptomatic branch duct IPMNs without mural nodules can be observed without resection for a considerably long time. This review addresses available data, current understanding, controversy, and future directions.     

Intraductal papillary mucinous neoplasm of the pancreas: diagnosis and treatment

Intraductal papillary mucinous neoplasm (IPMN) is characterized by cystic dilatation of the main and/or branch pancreatic duct. Only one-third of all patients are symptomatic, and others are diagnosed by chance. IPMNs are classified into 3 types: main duct, branch duct, and mixed IPMN. Most branch-type IPMNs are benign, while the other 2 types are frequently malignant. The presence of large mural nodules increases the possibility of malignancy in all types. Presence of a large branch-type IPMN and marked dilatation of the main duct indicate, at the very least, the existence of adenoma. Ultrasonography, endosonography, and intraductal ultrasonography clearly demonstrate ductal dilatation and mural nodules, and magnetic resonance pancreatography best visualizes the entire outline of IPMN. Not infrequently, synchronous or metachronous malignancy develops in various organs, including the pancreas. Prognosis is excellent after complete resection of benign and noninvasive malignant IPMNs. Asymptomatic branch-type IPMNs without mural nodules may be followed up without resection. Malignant IPMNs displaying acquired aggressiveness after parenchymal invasion require adequate lymph node dissection. Total pancreatectomy is needed for some IPMNs; its benefits, however, must be balanced against operative and postoperative risks because most IPMNs are slow growing and affect elderly people, and prognosis is favorable for IPMN patients with even malignant neoplasms.     

COMPARISON OF THE HEIGHT OF PAPILLARY TUMOR IN INTRADUCTAL PAPILLARY MUCINOUS NEOPLASM OF THE PANCREAS BETWEEN MEASURED PREOPERATIVE IMAGES AND RESECTED MATERIAL

The height of the mural nodules and papillary tumors in main pancreatic duct or dilated branch duct is the most important factor for diagnosis of intraductal papillary mucinous neoplasm (IPMN). In this study, the authors compared the height of the papillary lesions and mural nodules between the height of resected tissues and the height detected by the preoperative imaging tools (endoscopic ultrasonography [EUS] and intraductal ultrasonography [IDUS]) in 38 patients with IPMN. In 21 out of 23 cases of adenoma, and in cases with the non‐invasive cancer, the difference of the height of operative and preoperative analysis measured by EUS and IDUS was within 1–2 mm. EUS and IDUS are useful for diagnosis of degree of malignancy in IPMN.     

Endoscopic diagnosis of cystic lesions of the pancreas

Endoscopic methods are increasingly used in the diagnosis of cystic lesions of the pancreas. The two major endoscopic approaches are endoscopic ultrasonography (EUS) and transpapillary diagnosis. EUS‐guided fine‐needle aspiration cytology and EUS‐guided fine needle‐based confocal laser endomicroscopy have been used in the differential diagnosis of mucinous and non‐mucinous pancreatic cysts. EUS is the most sensitive modality for detecting mural nodules (MN) in intraductal papillary mucinous neoplasms (IPMN). Contrast‐enhanced harmonic EUS (CH‐EUS), as an add‐on to EUS, is useful for identifying and characterizing MN. Recent studies show that CH‐EUS has a sensitivity of 60–100% and a specificity of 75–92.9% for diagnosing malignant cysts. Intraductal ultrasonography and peroral pancreatoscopy are especially useful for detecting MN and IPMN. A recent meta‐analysis showed that cytological assessment of pancreatic juice using a transpapillary approach had a pooled sensitivity, specificity, and accuracy of 35.1%, 97.2%, and 92.9%, respectively, for diagnosing malignant IPMN. Further studies are warranted to determine the indications for each of these novel techniques in assessing cystic lesions of the pancreas.     

Intraductal papillary-mucinous tumors of the pancreas: differential diagnosis between benign and malignant tumors by endoscopic ultrasonography

OBJECTIVES: Recently, intraductal papillary-mucinous tumor (IPMT) of the pancreas has increasingly been recognized. However, differential diagnosis between benign and malignant IPMT is often difficult using conventional imaging modalities. The purpose of this study was to retrospectively investigate the value of endoscopic ultrasonography (EUS) for differentiating malignant from benign IPMT. METHODS: A total of 51 patients with IPMT were preoperatively examined by EUS. The endosonograhic findings were compared with histopathological findings of the resected specimens. RESULTS: In main duct type IPMT, the diameter of the main pancreatic duct (MPD) was > or =10 mm in seven of the eight malignant tumors, compared with two of the seven benign tumors (p < 0.05). In branch duct type IPMT, three of the four large tumors (>40 mm) with irregular thick septa were malignant lesions. In both main duct type IPMT and branch duct IPMT, eight patients had large mural nodules (>10 mm); seven of the eight tumors were malignant and one of the eight tumors was benign. When the tumor was diagnosed as malignant according to above three findings, EUS was able to differentiate between malignant and benign IPMT with an accuracy of 86%. CONCLUSIONS: Main duct type tumors with > or =10 mm dilated MPD, branch duct type tumors (>40 mm) with irregular septa, and large mural nodules (>10 mm) strongly suggest malignancy on EUS. EUS would be a useful modality for differentiating between benign and malignant IPMT.     

内镜诊治胰腺导管内乳头状粘液性肿瘤的应用

目的探讨胰腺导管内乳头状粘液性肿瘤(IPMN)的诊断、内镜下治疗,以提高对该疾病的认识及内镜对其诊断及治疗的意义。方法回顾性分析经内镜诊治的IPMN患者12例,总结并分析他们的一般情况、临床症状、影像学检查、实验室检查、内镜下治疗等方面资料。结果 12例IPMN患者以老年男性为主,无特异性临床表现,主要发生部位为胰头或钩突部,CT主要表现为囊实性低密度影,其内可有壁结节,胰管扩张伴或不伴胆管扩张,2例侵及胰腺实质。磁共振胰胆管造影(MRCP)主要表现为胰管扩张,胰腺萎缩,胰头部圆形高信号影。内镜下逆行胰胆管造影(ERCP)显示十二指肠乳头膨大,开口扩张,可见胶冻样粘液流出,胰管造影显示胰管全程扩张或胰头部囊状扩张,3例伴胆总管、肝内胆管扩张。9例行ERCP治疗,清除粘液栓并置入胰管支架,3例同时置入胆管支架。结论 IPMN是一种特殊类型的胰腺囊性疾病,影像学检查有其独特的表现,ERCP对其诊断及治疗有重要意义。     

Single-institution validation of the international consensus guidelines for treatment of branch duct intraductal papillary mucinous neoplasms of the pancreas

Background

The international consensus guidelines (the guidelines) for management of intraductal papillary mucinous neoplasms (IPMNs) of the pancreas recommend surgical resection of branch duct IPMNs with any of the following features: cyst size >30 mm, mural nodules, main pancreatic duct diameter >6 mm, positive cytology, and symptoms. The aim of this study was to evaluate the usefulness of these guidelines for resection of branch duct IPMNs.

Methods

We reviewed 84 consecutive patients with branch duct IPMNs who underwent surgical resection at our hospital between January 1984 and December 2007.

Results

Sixty-nine patients had indications for resection according to the guidelines. Malignant IPMNs had significantly larger cysts than benign tumors (P = 0.026). Patients with malignant IPMNs had significantly more indications for resection than those with benign IPMNs (2.6 ± 1.0 vs. 1.7 ± 0.9, P < 0.001), and 36 of the 37 patients with malignant IPMNs had indications. The sensitivity of the guidelines for predicting malignancy was 97.3%. One of 15 patients without indications had malignancy, and the specificity was low (29.8%).

Conclusions

The guidelines show a high sensitivity for predicting malignancy of branch duct IPMNs, but the specificity is low. The cyst size and the total number of indications in each patient should be taken into account when predicting the risk of malignancy for branch duct IPMNs.     

Optimal management of the branch duct type intraductal papillary mucinous neoplasms of the pancreas

GOALS: To determine the optimal management of the intraductal papillary mucinous neoplasms (IPMNs) according to the morphologic type based on distinguishing between benign and malignant diseases. BACKGROUNDS: IPMNs are increasingly recognized clinicopathologic entity. Extended pancreatic resection with radical lymph node dissection has been recommended for treatment. STUDY: A retrospective clinicopathologic study was carried out of the 57 cases with IPMNs who were treated between 1985 and 2001. Forty-three patients with IPMNs underwent resection, and 14 patients with small IPMNs were observed without resection. RESULTS: Among the 43 resected IPMNs, 25 were benign and 18 were malignant. Malignant tumors were significantly greater in diameter than benign tumors (52.9 vs. 30.2 mm, P< 0.05). All main duct type tumors with mural nodules were malignant. All branch duct type tumors less than 30 mm in diameter and without mural nodules were benign. Twelve branch duct type IPMNs size less than 30 mm were not resected and have not progressed. CONCLUSION: These results suggest that the branch duct type IPMNs less than 30 mm and without mural nodules is benign and might be treatable with limited resection or careful observation.     

Controversies in the management of pancreatic IPMN

Although considerable progress has been made in our understanding of intraductal papillary mucinous neoplasm (IPMN) of the pancreas, some issues still remain to be resolved. Uncertainty exists regarding the classification of IPMNs. The necessity of the mixed-type category of IPMN and whether such lesions should be defined radiographically or histologically needs to be determined. The preoperative distinction of branch duct IPMNs from nonmucinous cysts should be further investigated so that potentially malignant lesions can be identified and management strategies guided effectively. The role and safety of cystic fluid analysis remains to be clarified in this context. With regard to the diagnosis of malignancy in branch duct IPMNs, criteria for identifying malignancy need to be re-evaluated. The presence of mural nodules is a very reliable predictor; however, controversy exists over the value of size as a reliable indicator. Criteria with increased specificity are needed, perhaps including histological subtype of lesion, to reduce the false-positive rate of the present criteria. Finally, the best modality and interval for surveillance of branch duct IPMNs requires determination because of its significance in terms of malignant transformation, development of distinct ductal adenocarcinoma and disease recurrence after resection.     

Cytological and Cyst Fluid Analysis of Small (≤3 cm) Branch Duct Intraductal Papillary Mucinous Neoplasms Adds Value to Patient Management Decisions

Background/Aim: Management of patients with small (1–3 cm) branch duct intraductal papillary mucinous neoplasms (IPMN) is a challenge. Symptoms, dilated duct, mural nodule or positive cytology have been proposed as parameters for resection. The aim of our study was to compare this proposed algorithm to one that incorporates cytology with less than malignant epithelial cells and cyst fluid carcinoembryonic antigen (CEA). Methods: A retrospective study was conducted. Results: There were 14 nonmalignant and 6 malignant cysts with 3 invasive IPMN. None were associated with a dilated duct and none had positive cytology. Only a mural nodule was significant by univariate analysis for the detection of malignancy (p = 0.01) and invasion (p = 0.009). The detection of atypical epithelial cells or a cyst fluid CEA of >2,500 ng/ml was more accurate for the detection of malignancy than using the recommended algorithm. Conclusions: The presence of a mural nodule in a small branch duct IPMN is a predictor of malignancy and invasion by univariate analysis. Recognition of an atypical epithelial cell component in contrast to positive cytology or a cyst fluid CEA of >2,500 ng/ml is more accurate than the recommended algorithm and adds value to the preoperative assessment of clinically diagnosed small branch duct IPMN.     

Differential diagnosis of benign and malignant branch duct intraductal papillary mucinous neoplasm using contrast-enhanced endoscopic ultrasonography

AIM: To elucidate the role of contrast-enhanced endoscopic ultrasonography (CE-EUS) in the diagnosis of branch duct intraductal papillary mucinous neoplasm (BD-IPMN).METHODS: A total of 50 patients diagnosed with BD-IPMN by computed tomography (CT) and endoscopic ultrasonography (EUS) at our institute were included in this study. CE-EUS was performed when mural lesions were detected by EUS. The diagnostic accuracy for identifying mural nodules (MNs) was evaluated by CT, EUS, and EUS combined with CE-EUS. In the patients who underwent resection, the accuracy of measuring MN height with each imaging modality was compared. The cut-off values to diagnose malignant BD-IPMNs based on MN height for each imaging modality were determined using receiver operating characteristic curve analysis.RESULTS: Fifteen patients were diagnosed with BD-IPMN with MNs and underwent resection. The remaining 35 patients were diagnosed with BD-IPMN without MNs and underwent follow-up monitoring. The pathological findings revealed 14 cases with MNs and one case without. The accuracy for diagnosing MNs was 92% using CT and 72% using EUS; the diagnostic accuracy increased to 98% when EUS and CE-EUS were combined. The accuracy for measuring MN height significantly improved when using CE-EUS compared with using CT or EUS (median measurement error value, CT: 3.3 mm vs CE-EUS: 0.6 mm, P < 0.05; EUS: 2.1 mm vs CE-EUS: 0.6 mm, P < 0.01). A cut-off value of 8.8 mm for MN height as measured by CE-EUS improved the accuracy of diagnosing malignant BD-IPMN to 93%.CONCLUSION: Using CE-EUS to measure MN height provides a highly accurate method for differentiating benign from malignant BD-IPMN.     

Current roles of endoscopy in the management of intraductal papillary mucinous neoplasm of the pancreas

Intraductal papillary mucinous neoplasm (IPMN) of the pancreas is characterized by intraductal papillary proliferation of mucin‐producing epithelial cells that exhibit various degrees of dysplasia. IPMN is classified into four histological subtypes (gastric, intestinal, pancreatobiliary, and oncocytic) according to its histomorphological and immunohistochemical characteristics. Endoscopic retrograde cholangiopancreatography plays a crucial role in the evaluation of these features of IPMN. Endoscopic ultrasonography (EUS) has proven to be more sensitive than computed tomography or magnetic resonance imaging for early detection of malignancy. The present review addresses the current roles of endoscopy and related techniques in the management of IPMN. The particular focus is on diagnosing IPMN and malignancy within IPMN, detecting pancreatic cancer concomitant with IPMN, differentiating the epithelial subtypes of IPMN, determining the optimal strategy for the management of branch duct IPMN, and discussing innovative endoscopic technology related to IPMN. The disadvantages of endoscopic examinations of IPMN and different attitudes toward EUS‐guided fine‐needle aspiration for IPMN between Japan (negative) and other countries (active) are also discussed.     

LATERAL SPREAD ALONG THE MAIN PANCREATIC DUCT IN BRANCH‐DUCT INTRADUCTAL PAPILLARY‐MUCINOUS NEOPLASMS OF THE PANCREAS: USEFULNESS OF INTRADUCTAL ULTRASONOGRAPHY FOR ITS EVALUATION

Background: Intraductal papillary mucinous neoplasms (IPMN) of the pancreas tend to spread intraepithelially along the pancreatic duct wall. We evaluated histopathological intraductal lateral spread (LS) along the main pancreatic duct (MPD) from branch‐duct IPMN and investigated the usefulness of intraductal ultrasonography (IDUS) for its preoperative diagnosis. Patients and Methods: Twenty‐four patients with branch‐duct IPMN who had undergone preoperative IDUS and surgery were reviewed clinicopathologically. The prevalence and histological length of LS along the MPD from branch‐duct IPMN, characteristics of the patients with LS, and efficacy of LS assessment by IDUS were examined. Results: LS along the MPD was observed in 54% of the subjects. In the group of patients with LS, its mean length was 25.2 ± 16.8 mm (5–50 mm) and the diameter of the MPD was 6 mm or greater. Of the patients with LS, those in whom the length of LS along the MPD was longer than the diameter of the cystically dilated branch accounted for 30%. The diameter of the MPD in the group with LS was significantly greater than that in the group without LS (P = 0.03). The sensitivity, specificity, and overall accuracy of IDUS in the detection of LS were 92%, 91%, and 92%, respectively. Conclusion: LS along the MPD was detected in about half of the resected cases of branch‐duct IPMN. Preoperative transpapillary IDUS may be beneficial for the determination of the resection line, especially in those branch‐duct IPMN patients in whom the MPD is 6 mm or greater in diameter.     

Analysis of clinicopathological features and predictors of malignancy in intraductal papillary mucinous neoplasms of the pancreas

BACKGROUND/AIMS: Intraductal papillary mucinous neoplasms (IPMNs) are increasingly recognized, but it is very difficult to evaluate accurately the malignancy of these neoplasms by modern imaging. We reviewed our experience in order to elucidate predictors of tumor malignancy, invasiveness, and outcome. METHODOLOGY: The clinicopathological features and surgical outcomes of 57 patients with IPMNs who underwent surgery in Nagoya University Hospital were analyzed. RESULTS: The histological diagnosis was adenoma in 40, borderline in 1, carcinoma in situ (CIS) in 7, and invasive carcinoma in 9 patients. Patients with invasive carcinomas had significantly shorter survival rates than patients with benign IPMNs or CIS (p < 0.0001). Multivariate analyses revealed that the main duct or the combined type was significantly predictive of malignancy, and both main duct or combined type and diabetes mellitus were associated significantly with invasive carcinoma. CONCLUSIONS: IPMNs generally grow slowly, but have a malignant potential that warrants radical surgical treatment when the tumor component invades the parenchyma. Our results suggest that the above factors should be considered in surgical management. The main duct type of IPMN or IPMN with mural nodules is potentially malignant or invasive. Therefore, radical operative management is indicated in these IPMNs.     

Clinical management of intraductal papillary mucinous tumors of the pancreas based on imaging findings

The aim of this study was to assess the imaging findings of pathologically proven intraductal papillary-mucinous tumors of the pancreas and the natural history of follow-up cases, and to optimize the therapeutic management of patients with these tumors according to their imaging findings. All nine patients with main duct type tumors were histologically diagnosed as having adenocarcinoma or adenoma, with no hyperplastic lesion. The images failed to discriminate between the two histologic types. In 26 patients with branch duct type tumors, all but one with intraductal mural nodules or tumors of > or = 30 mm had adenocarcinoma or adenoma, regardless of the caliber of the main duct. Of the nine patients with tumors < 30 mm and no mural nodules. three had adenoma, and six had hyperplasia. All of four patients had hyperplasia, with the additional caliber of the main duct being < 6 mm. In a series of 23 cases in which the patient was followed-up, no apparent progression was found in 17 patients who had no mural nodules and tumors of < 30 mm. Given these results, patients with main duct type tumors, and those with branch duct type tumors showing mural nodules or a tumor diameter of > or = 30 mm, are at high risk of developing neoplasms, including adenocarcinoma, for which surgical resection should be considered, whereas those patients with tumors < 30 mm and no mural nodules can be followed.