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

The Natural Course of Pancreatic Cysts in Inflammatory Bowel Disease: Results of a Long-term Follow-up

OBJECTIVES

The natural course of pancreatic cysts in inflammatory bowel disease (IBD) is unknown. We aim to describe the natural course of pancreatic cysts in IBD and evaluate long-term outcomes.

METHODS

A database of patients with abdominal imaging diagnosis of pancreatic cysts (2008-2019) was reviewed. Patients with IBD and pancreatic cysts (study group) and pancreatic cysts without IBD (controls) were selected. Outcomes were measured at 1, 3, 5, and 10 years. Several logistic regression models were used for analysis.

RESULTS

Of the 1789 patients evaluated, 1690 had pancreatic cysts without IBD, and 78 had IBD and pancreatic cysts. Majority of cysts were intraductal papillary mucinous neoplasms. Patients with IBD and pancreatic cysts were more likely to be diagnosed with pancreatic cysts at a younger age (P < 0.001) and were more likely to undergo surgical intervention at a younger age (P < 0.001).

CONCLUSIONS

This is the first study to evaluate the natural course of pancreatic cysts in IBD patients. Patients with IBD were more likely to have pancreatic cysts detected at a younger age. Despite the early presentation, there were no differences in long-term outcomes. Patients with IBD with pancreatic cysts should be managed similarly to those without IBD.

Histological features of autoimmune pancreatitis and IgG4-related sclerosing cholangitis with a correlation with imaging findings

Autoimmune pancreatitis (AIP) is characterized by a tumefactive inflammatory lesion resembling pancreatic carcinoma. Type 1 AIP is a pancreatic manifestation of IgG4-related disease characterized by unique histological features that can be identified on imaging. The capsule-like rim, which is a collar of hypertrophic lesion surrounding the pancreas, consists of lymphoplasmacytic infiltration and fibrosis, and storiform fibrosis is often identified. Hypertrophic lesions of various microscopic architectures such as the ducts, veins (obliterative phlebitis), arteries (periarteritis), and nerves are observed without parenchymal damage. The pancreatic lobules keep their contours, but the acinar cells are diminished and replaced by numerous inflammatory cells. These features provide clues to arrive at a diagnosis of type 1 AIP and to distinguish it from pancreatic carcinoma on imaging. In contrast, type 2 AIP is an epithelium-centered inflammation involving the ducts and lobules. Neutrophilic infiltration in the epithelium and/or lumens (granulocytic epithelial lesion) is a characteristic finding. Lobular swelling due to inflammation is the cause of pancreatic enlargement. IgG4-related sclerosing cholangitis is histologically similar to the hypertrophic ductal lesion in type 1 AIP and characterized by wall thickening due to inflammation and luminal stenosis. The epithelium is intact, which is different from bile duct carcinomas and primary sclerosing cholangitis, the latter of which is characterized by inflammation targeting the epithelium. Although the histological features of type 1 AIP and IgG4-related sclerosing cholangitis are unique, the biopsy diagnosis of these diseases has limitations, which should be recognized by clinicians.

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.

Rare coincidence of intraductal papillary mucinous neoplasm and type 1 autoimmune pancreatitis

The present case involved a 60-year-old man with autoimmune pancreatitis (AIP). While his AIP was in remission for 6 years, a follow-up CE-CT revealed a dilated main pancreatic duct (MPD) and an enhanced mural nodule. Fluorodeoxyglucose uptake was positive on positron emission tomography. Endoscopic retrograde pancreatography showed a filling defect of the MPD, and pancreatoscopy revealed a nodule partially covered with papillary lesions. Although a repeat biopsy revealed no evidence of malignancy, we speculated that there was a high likelihood of main-duct-type intraductal papillary mucinous neoplasm (IPMN)-derived carcinoma concomitant with AIP. Subsequently, the patient underwent subtotal stomach-preserving pancreaticoduodenectomy. A surgical specimen showed a 35 mm protuberant papillary lesion with abundant stroma, located in the main duct of the pancreas. Further histological evaluation revealed that the nodule was predominantly composed of IPMN with low-grade dysplasia, which was accompanied by abundant IgG4-positive lymphoplasmacytic infiltration, and fibrosis existed predominantly around the IPMN. The epithelium of the cyst showed mucinous hyperplasia with focal papillary structures of gastric phenotype (MUC5A+, MUC6+, MUC1-, MUC2-, CDX-). After surgical resection, we did not find any imaging evidence suggesting a recurrent tumor and AIP relapse in the remnant pancreas. In conclusion, we report a case of IPMN coincidentally found in a patient with type 1 AIP. Active AIP may exaggerate the morphology of IPMN, and careful evaluation should be performed to select appropriate management.

Multilocular Cyst of Type 1 Autoimmune Pancreatitis Masquerading as Cancerization of Intraductal Papillary Mucinous Neoplasm

A small proportion of intraductal papillary mucinous neoplasms (IPMNs) are accompanied by type 1 autoimmune pancreatitis (AIP); however their clinical courses and image characteristics have not been fully reported. A 65-year-old woman was referred to our hospital for the examination of a pancreatic head cyst that had shown exacerbation for two years. Several images demonstrated a multilocular cyst with a symmetrically thickened, enhanced, cyst wall. Cancerization of IPMN was suspected, and pancreatoduodenectomy was performed. The resected specimens showed a multilocular cyst with solid areas. The solid areas demonstrated pathological findings that corresponded with type 1 AIP. Papillary epithelia suggestive of IPMN was recognized in some parts of the cystic wall.

Coexisting Mucinous Cystic Neoplasm of the Pancreas and Type 1 Autoimmune Pancreatitis

Type 1 autoimmune pancreatitis (AIP1) is an IgG4-related systemic disease that mimics tumors. We report a rare case of AIP1 accompanied by mucinous cystic neoplasm (MCN). A pancreatic lesion was incidentally detected in a woman in her 60s. After 6 years of follow-up, the lesion abruptly increased in size. Computed tomography showed a 3.5 cm unilocular cyst in the tail of the pancreas and distal pancreatectomy was performed. On microscopic examination, the cyst was lined by mucinous and non-mucinous epithelial cells with mild cytologic atypia. The surrounding stroma comprised ovarian-type spindle cells with progesterone receptor positivity. The pericystic pancreas exhibited multifocal lymphoid follicles, lymphoplasmacytic infiltrations, obliterative phlebitis, and storiform fibrosis. IgG4-positive plasma cell infiltration (215 cells high-power field) and the IgG4/IgG ratio (57%) were increased. Cases of MCN coexisting with AIP1 are extremely rare; only two such cases have been reported in the English-language literature. This third case featured low-grade MCN with AIP1.

The Role of Endoscopic Ultrasound-guided Drainage for Autoimmune Pancreatitis-associated Pancreatic Cysts: A Report of Five Cases and a Literature Review

Objective Autoimmune pancreatitis (AIP) has been recognized as a benign disease, which that shows a prompt response to corticosteroid treatment (CST). It was previously believed to not be associated with cyst formation; however, a few cases of AIP-associated pancreatic cyst (PC) have been reported. Some cases were reported to have been effectively treated by CST, while others were refractory to CST. Many of the patients received interventional treatment. Until now, there has been no consensus on the therapeutic strategies for AIP-associated PC. The aim of the present study is to describe a therapeutic strategy for this condition. Methods We conducted a retrospective study of 5 cases of AIP-associated PC that were treated by endoscopic ultrasonography-guided pancreatic fluid collection drainage (ESPD) or CST at Tokyo Medical University Hospital between March 2012 and October 2016, analyzed the therapeutic outcomes, and performed a literature review. Results The initial treatments included CST (n=2) and ESPD (n=3). All of the PCs disappeared after treatment In 1 of the patients who received CST case and 3 of the patients who received ESPD; however, the PC did not disappear in one of the patients who received CST (corticosteroid maintenance therapy), even after the dose of corticosteroids was increased; ESPD was eventually performed and the PC disappeared. There were no procedure-related complaints. Conclusion We propose that CST be administered as the first-line treatment for AIP-associated PC, particularly in cases of PC without a history of CST. However, ESPD can be applied to treat cases of corticosteroid refractory PC.

Signet-ring Cell Carcinoma Derived from a Main Duct-type Intraductal Papillary Mucinous Neoplasm of the Pancreas: A Case Report with Long-term Follow-up

We herein report the case of a 74-year-old man who underwent surgery 9 years after his initial visit and who was pathologically diagnosed with signet-ring cell carcinoma (SRCC) derived from a main-duct-type intraductal papillary mucinous neoplasm (MD-IPMN). At the first imaging examination, only a small pancreatic cyst with mild dilation of the main pancreatic duct (MPD) was detected in the pancreatic head. Eventually, MD-IPMN with mural nodules and MPD dilation (30 mm) developed in the pancreatic body, while the pancreatic head cyst remained unchanged. Total pancreatectomy was performed and the MD-IPMN was pathologically diagnosed as SRCC derived from an intestinal-type MD-IPMN.

Association of IgG4 response and autoimmune pancreatitis with intraductal papillary-mucinous neoplasms

OBJECTIVES

Concurrent intraductal papillary-mucinous neoplasm (IPMN) and autoimmune pancreatitis (AIP) was observed in a patient (index case) at our institution. Cases of coincidental IPMN and type 1 AIP and concurrent ductal adenocarcinoma (PDAC) and AIP have been previously reported. In this study we evaluate the hypothesis that IPMN elicits an IgG4 response.

METHODS

Twenty-one pancreases (including the index case) with IPMN resected at our institution were studied. H&E stained slides were reviewed and blocks of peritumoral pancreas were immunostained with IgG4 to look for IgG4-positive plasma cells.

RESULTS

We found evidence of variable IgG4 overexpression in 4/21 (19%) of IPMN. These included the index case and three others without stigmata of AIP.

CONCLUSION

A small subset of pancreatic neoplasms including intraductal papillary-mucinous neoplasms (IPMN) is associated with an IgG4 autoimmune response that sometimes progresses to peritumoral type 1 AIP and less often to diffuse AIP and IgG4-related systemic disease.

Branch Duct Intraductal Papillary Mucinous Neoplasms of the Pancreas Involving Type 1 Localized Autoimmune Pancreatitis with Normal Serum IgG4 Levels Successfully Diagnosed by Endoscopic Ultrasound-guided Fine-needle Aspiration and Treated without Pancreatic Surgery

We herein report a 68-year-old man with branch duct intraductal papillary mucinous neoplasms of the pancreas (BD-IPMNs) involving type 1 localized autoimmune pancreatitis (AIP) with normal serum IgG4 levels. Although he was referred to our medical center due to suspicion of pancreatic cancer concomitant with BD-IPMNs, endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) revealed a mass suspected of being pancreatic cancer to be type 1 AIP. Steroid administration notably reduced the mass. Although the clinical diagnosis of pancreatic masses in patients with IPMN can be occasionally challenging, performing a pathological examination by EUS-FNA may prevent unnecessary pancreatic surgery in cases of possible AIP.

Intraductal papillary mucinous neoplasm of the pancreas, one manifestation of a more systemic disease?

BACKGROUND

Several studies have demonstrated a high prevalence of extrapancreatic malignancies, and an association with autoimmune pancreatitis in patients with intraductal papillary mucinous neoplasm (IPMN). We hypothesized that IPMNs were associated with an increase rate of systemic diseases.

METHODS

From 1996 to 2013, a retrospective analysis of a prospectively collected database was performed and supplemented with electronic medical charts review.

RESULTS

Two hundred twenty extrapancreatic malignancies were found in 185 patients (22%) compared with expected 5% in the general population. Colorectal, lung, and renal cell carcinoma had significant observed/expected ratios (P < .0001). One hundred ten synchronous autoimmune diseases were found in 96 patients (11%). Systemic lupus erythematosus, rheumatoid arthritis, and inflammatory bowel disease showed statistically significant observed/expected ratios (P < .0001, .01, and <.0001, respectively). There was no impact of immunosuppressive treatment on the IPMN subtype and malignancy rate.

CONCLUSIONS

IPMN are associated with surprisingly high rates of autoimmune diseases suggesting that IPMN might be 1 manifestation of a more systemic disease.

Cystic Lesions in Autoimmune Pancreatitis

Autoimmune pancreatitis (AIP) can be chronic or recurrent, but frequently completely reversible after steroid treatment. A cystic lesion in AIP is a rare finding, and it can mimic a pancreatic cystic neoplasm. Difficulties in an exact diagnosis interfere with treatment, and surgery cannot be avoided in some cases. We report the history of a 63-year-old male presenting with jaundice and pruritus. AIP was confirmed by imaging and elevated IgG4 blood levels, and the patient completely recovered after corticosteroid therapy. One year later, he presented with a recurrent episode of AIP with elevated IgG4 levels, accompanied by the appearance of multiple intrapancreatic cystic lesions. All but 1 of these cysts disappeared after steroid treatment, but the remaining cyst in the pancreatic head was even somewhat larger 1 year later. Pancreatoduodenectomy was finally performed. Histology showed the wall of the cystic lesion to be fibrotic; the surrounding pancreatic tissue presented fibrosis, atrophy and lymphoplasmacytic infiltration by IgG4-positive cells, without malignant elements. Our case illustrates the rare possibility that cystic lesions can be part of AIP. These pseudocysts appear in the pancreatic segments involved in the autoimmune disease and can be a consequence of the local inflammation or related to ductal strictures. Steroid treatment should be initiated, after which these cysts can completely disappear with recovery from AIP. Surgical intervention may be necessary in some exceptional cases.