A case of minute intraductal papillary mucinous tumor of the pancreas presenting with recurrent acute pancreatitis

Peritoneal Metastases After Intraductal Papillary Mucinous Neoplasm Resection: How Common are They?

INTRODUCTION

Peritoneal metastases (PMs) following resection of pancreatic intraductal papillary mucinous neoplasms (IPMNs) are rare. Consequently, prevalence, risk factors, and prognosis are not well known. We reviewed our institution's experience and published literature to further characterize the scope of this phenomenon.

METHODS

All pancreatectomy cases (556 patients) performed at a tertiary care center between 2010 and 2020 were reviewed to identify IPMN diagnoses. Patients with adenocarcinoma not arising from IPMN, or a history of other malignancies were excluded.

RESULTS

Seventy-eight patients underwent pancreatectomy with IPMN on final pathology at our institution; 51 met inclusion criteria. Of these, there were five cases of PMs (4:1 females:males). Four had invasive carcinoma arising from IPMN and one had high-grade dysplasia at the index operation. Female sex and invasive histology were significantly associated with PM (P < 0.05). PM rates by sex were 3% (95% confidence interval [CI]: 0.5-15) in males and 22% (95% CI: 9-45) in females. Rates by histology were 2.9% (95% CI: 0.5-15) for noninvasive IPMN, and 23.5% (95% CI: 9.5-47) for invasive carcinoma arising from IPMN. Median interval from surgery to PMs was 7 mo (range: 3-13).

CONCLUSIONS

PMs following IPMN resection are rare but may be more common in patients with invasive histology. Although rare, PMs can arise in patients with noninvasive IPMNs. Further studies on pathophysiology and risk factors of PM following IPMN resection are needed and may reinforce adherence to guidelines recommending long-term surveillance.

Repeating regional acute pancreatitis in the head of the pancreas caused by intraductal papillary mucinous neoplasms in the tail: report of a case

Intraductal papillary mucinous neoplasm (IPMN) of the pancreas is a distinct entity characterized by papillary proliferations of mucin-producing epithelial cells with excessive mucin production and cystic dilatation of the pancreatic ducts. The clinical presentation often involves recurrent episodes of pancreatitis associated with the temporal obstruction of the main pancreatic duct caused by the hypersecretion of mucin. We herein describe a case in which the patient repeatedly experienced the occurrence of idiopathic acute pancreatitis in the head of the pancreas over a 9-year period, and who was ultimately was cured by distal pancreatectomy for IPMNs in the pancreatic tail. This case illustrates the potential pitfalls in the diagnosis of IPMNs owing to a discrepancy between the site of pancreatitis and that of the IPMN. The possible mechanisms linking acute pancreatitis with the formation of IPMNs are also reviewed.

Pancreatitis is frequent among patients with side-branch intraductal papillary mucinous neoplasia diagnosed by EUS

BACKGROUND

Because of greater recognition and improved imaging capabilities, intraductal papillary mucinous neoplasms (IPMNs) are being diagnosed with increasing frequency. IPMNs of the main pancreatic duct cause symptoms and lead to pancreatitis. Side-branch (SB) IPMNs are thought to cause symptoms less frequently, and their association with pancreatitis is not well defined.

OBJECTIVE

Our purpose was to ascertain whether an association exists between SB-IPMN and pancreatitis.

DESIGN

Single-center, retrospective study.

SETTING

Academic medical center.

PATIENTS

A total of 305 patients underwent EUS examinations between October 2002 and October 2006 for pancreatic cystic lesions.

MAIN OUTCOME MEASUREMENT

The main outcome measure was the frequency of acute or chronic pancreatitis that was not procedurally related.

RESULTS

Thirty-two patients had SB-IPMNs, and 11 (34%) had pancreatitis. Three patients reported a single episode, and 8 patients reported having recurrent episodes of pancreatitis. Overall, 17 (53%) patients had symptoms possibly attributable to SB-IPMN. Female sex (73% vs 38%) and multiple pancreatic lesions (54% vs 24%) were more commonly seen in those with pancreatitis, but were not statistically significant factors. Larger cyst size or cyst fluid marker levels did not appear associated with pancreatitis occurrence. EUS-FNA demonstrated communication with the pancreatic duct in 94% and thick, mucinous fluid in 84%.

LIMITATIONS

Single-center, retrospective study.

CONCLUSIONS

Pancreatitis was frequently associated with the presence of SB-IPMNs in our referral practice. SB-IPMNs should be considered in the differential diagnosis of patients with recurrent pancreatitis with cystic lesions seen on imaging studies. EUS-FNA was the most useful modality in helping to differentiate SB-IPMNs from other lesions.

Correlation between CT patterns and pathological classification of intraductal papillary mucinous neoplasm

OBJECTIVE

To examine CT patterns of intraductal papillary mucinous neoplasm (IPMN), analyze their correlation with pathologic classification, and discuss the value of CT in the diagnosis and differential diagnosis of IPMN.

METHODS

CT patterns of 39 IPMN patients, whose clinical data were complete and whose diagnosis was confirmed by surgery and pathology, were classified into three types: (1) simple main pancreatic duct (MPD) dilation type, (2) MPD dilation with pancreatic cystic lesion type, and (3) simple pancreatic cystic lesion type. Correlations between the three CT types and Takada pathologic classification (MPD type, furcation type and mixture type) were analyzed. The 39 IPMN cases were pathologically classified as the benign group and the malignant/borderline group. CT characteristics including the presence or absence of mural nodules, intrafocal partitions, focal size and the degree of MPD and common bile duct (CBD) dilation were analyzed statistically.

RESULTS

A correlation was found between the CT simple MPD dilation type and the pathological MPD type, between the MPD dilation with pancreatic cystic lesion type and the furcation and mixture types, and between the simple cystic lesion type and the furcation type (p<0.001). The benign rate was 92% in patients without intrafocal mural nodules, and 42% in patients with intrafocal mural nodules. The difference between the two groups was statistically significant (p=0.003). The presence or absence of intrafocal partitions was not correlated with benignancy or malignancy (p=0.793). The maximum diameter of malignant/borderline lesions was bigger than that of benign ones (p=0.016). There was no significant difference in MPD and CBD diameters between the benign and malignant/borderline groups. Regardless of pathological classification, the MPD diameter was larger than the CBD diameter in all cases (p=0.02).

CONCLUSION

The three CT types of IPMN well correlated with the pathologic classification, which is helpful for analyzing CT manifestations and improving the accuracy of diagnosis. MPD dilation is usually larger than CBD dilation in IPMN patients, which is also helpful in the diagnosis and differential diagnosis of IPMN in the context of other related findings.