Diffuse Pancreatic Cancer Mimicking Autoimmune Pancreatitis

Diffuse Type Pancreatic Ductal Adenocarcinoma: The Linitis Plastica Type of the Pancreas

Pancreatic malignant tumors are diverse and characterized by aggressive nature with high mortality rates. Pancreatic ductal adenocarcinoma (PDAC) is the most common type of pancreatic malignant tumors and accounts for approximately 90% of pancreatic malignancies. A subtype of PDAC, diffuse type PDAC (DTP), is a very rare and underreported tumor, known for its aggressive traits. Although little data are available about this tumor subtype characteristics, it usually presents with distinct features that are different from the known ones in PDAC. Herein, we present a case of a 61-year-old male patient, who presented with abdominal discomfort, weight loss and newly diagnosed diabetes mellitus. An abdominal computed tomography (CT) scan showed an ill-defined mass at the uncinate process with diffuse dilatation of the main pancreatic duct. Endoscopic ultrasound (EUS)-guided fine-needle biopsy showed cellular atypia suspicious for malignancy. The patient underwent total pancreatectomy with Roux-en-Y reconstruction. His postoperative course was uneventful. The final histopathological report showed well-differentiated diffuse ductal adenocarcinoma involving the pancreatic head, neck and body.

Differential Diagnosis of Pancreatic Cancer and its Mimicking Lesions

Pancreatic cancer is usually detected through contrast-enhanced CT and MRI. However, pancreatic cancer is occasionally overlooked because of its small size or is misdiagnosed as other conditions due to atypical imaging features that present diagnostic challenges. Considering the rapid growth and poor prognosis associated with pancreatic cancer, the ability to accurately detect and differentiate pancreatic lesions is crucial for appropriate surgical intervention. Reviewing diverse challenging cases of pancreatic cancer at an early stage and other mimicking lesions may help us accurately interpret the imaging features of pancreatic cancer on CT and MRI scans. Therefore, we aimed to illustrate various imaging features of pancreatic cancer and its mimicking lesions and provide valuable insights for differential diagnosis.

Diagnostic Differentiation between Pancreatitis and Pancreatic Cancer: A Scoping Review

Pancreatitis, encompassing acute and chronic forms, and pancreatic cancer pose significant challenges to the exocrine tissue of the pancreas. Recurrence rates and complications following acute pancreatitis episodes can lead to long-term risks, including diabetes mellitus. Chronic pancreatitis can develop in approximately 15% of cases, regardless of the initial episode's severity. Alcohol-induced pancreatitis, idiopathic causes, cigarette smoking, and hereditary pancreatitis contribute to the progression to chronic pancreatitis. Chronic pancreatitis is associated with an increased risk of pancreatic cancer, with older age at onset and smoking identified as risk factors. This scoping review aims to synthesise recent publications (2017-2022) on the diagnostic differentiation between pancreatitis and pancreatic cancer while identifying knowledge gaps in the field. The review focuses on biomarkers and imaging techniques in individuals with pancreatitis and pancreatic cancer. Promising biomarkers such as faecal elastase-1 and specific chemokines offer non-invasive ways to assess pancreatic insufficiency and detect early biomarkers for chronic pancreatitis. Imaging techniques, including computed tomography (CT), magnetic resonance imaging (MRI), endoscopic ultrasound (EUS), and positron emission tomography (PET), aid in differentiating between chronic pancreatitis and pancreatic cancer. However, accurately distinguishing between the two conditions remains a challenge, particularly when a mass is present in the head of the pancreas. Several knowledge gaps persist despite advancements in understanding the association between pancreatitis and pancreatic cancer, including the correlation between histopathological grading systems, non-invasive imaging techniques, and biomarkers in chronic pancreatitis to determine the risk of progression to pancreatic cancer, as well as differentiating between the two conditions. Further research is necessary to enhance our understanding of these aspects, which can ultimately improve the diagnosis and management of pancreatitis and pancreatic cancer.

Pancreatic Cancer and Its Mimics

Pancreatic ductal adenocarcinoma (PDAC) is the most common primary pancreatic malignancy, ranking fourth in cancer-related mortality in the United States. Typically, PDAC appears on images as a hypovascular mass with upstream pancreatic duct dilatation and abrupt duct cutoff, distal pancreatic atrophy, and vascular encasement, with metastatic involvement including lymphadenopathy. However, atypical manifestations that may limit detection of the underlying PDAC may also occur. Atypical PDAC features include findings related to associated conditions such as acute or chronic pancreatitis, a mass that is isointense to the parenchyma, multiplicity, diffuse tumor infiltration, associated calcifications, and cystic components. Several neoplastic and inflammatory conditions can mimic PDAC, such as paraduodenal "groove" pancreatitis, autoimmune pancreatitis, focal acute and chronic pancreatitis, neuroendocrine tumors, solid pseudopapillary neoplasms, metastases, and lymphoma. Differentiation of these conditions from PDAC can be challenging due to overlapping CT and MRI features; however, certain findings can help in differentiation. Diffusion-weighted MRI can be helpful but also can be nonspecific. Accurate diagnosis is pivotal for guiding therapeutic planning and potential outcomes in PDAC and avoiding biopsy or surgical treatment of some of these mimics. Biopsy may still be required for diagnosis in some cases. The authors describe the typical and atypical imaging findings of PDAC and features that may help to differentiate PDAC from its mimics. ©RSNA, 2023 Online supplemental material is available for this article. Quiz questions for this article are available through the Online Learning Center. See the invited commentary by Zins in this issue.

Diffuse-Type Pancreatic Ductal Adenocarcinoma Mimicking Autoimmune Pancreatitis

Pancreatic ductal adenocarcinoma (PDAC) classically presents as a solitary mass on cross-sectional imaging. Diffuse-type PDAC is an unusual variant that accounts for 1%-5% of PDACs. Owing to its rarity, there are no established radiographic or endosonographic definitions. We report a unique case of diffuse-type PDAC presenting with imaging findings of 2 distinct masses in the pancreatic head and tail and with endoscopic ultrasound findings of diffuse gland enlargement mimicking autoimmune pancreatitis. The case illustrates the importance of sampling several areas of the pancreas when diffuse enlargement is present on endoscopic ultrasound and multiple masses are seen on cross-sectional imaging.

Gastric linitis plastica with autoimmune pancreatitis diagnosed by an endoscopic ultrasonography-guided fine-needle biopsy: A case report

BACKGROUND

Gastric linitis plastica (GLP) is a subset of gastric cancer with a poor prognosis. It is difficult to obtain a definitive diagnosis by endoscopic mucosal biopsies, and the usefulness of an endoscopic ultrasonography-guided fine-needle biopsy (EUS-FNB) for GLP has been recently reported. Meanwhile, autoimmune diseases are occasionally known to coexist with malignant tumors as paraneoplastic syndrome. We herein report the usefulness of an EUS-FNB for detecting GLP and the possibility of paraneoplastic syndrome coexisting with GLP.

CASE SUMMARY

An 81-year-old man was admitted to our hospital for a 1-mo history of epigastric pain that increased after eating. His laboratory data revealed high levels of serum carbohydrate antigen 19-9 and immunoglobulin-G4. Endoscopic examinations showed giant gastric folds and reddish mucosa; however, no epithelial changes were observed. The gastric lumen was not distensible by air inflation, suggesting GLP. Computed tomography showed the thickened gastric wall, the diffuse enlargement of the pancreas, and the peripancreatic rim, which suggested autoimmune pancreatitis (AIP) coexisting with GLP. Because the pathological findings of the endoscopic biopsy showed no malignancy, he underwent an EUS-FNB and was diagnosed with GLP. He received chemotherapy for unresectable gastric cancer due to peritoneal metastasis, after which both the gastric wall thickening and diffuse enlargement of the pancreas were improved.

CONCLUSION

An EUS-FNB for GLP with a negative endoscopic biopsy is useful, and AIP may develop as a paraneoplastic syndrome.

Association of oral microbiome and pancreatic cancer: a systematic review and meta-analysis

BACKGROUND

Oral microbiota reported to be associated with pancreatic diseases, including pancreatic cancer. However, the association of oral microbiome and pancreatic cancer has not been reviewed systematically.

OBJECTIVES

To systematically investigate the association between the oral microbiome and pancreatic cancer risk.

DESIGN

A systematic review and meta-analysis.

DATA SOURCES AND METHODS

Systemic searches were conducted using PubMed, Medline, Cochrane Library, and Embase databases without any language restriction from conception to August 29, 2020. The studies that evaluated the association of oral microbiome and pancreatic cancer risk were included in this meta-analysis.

RESULTS

The six included studies encompassed a total of 863 pancreatic cancer cases and 906 controls. Four studies reported the overall oral microbiome in pancreatic cancer cases. A total of 12-17 species/clusters were correlated with pancreatic cancer. Three studies reported the odds ratios (ORs) or relative abundance of several oral microbiomes pieces/clusters, and the majority were associated with pancreatic cancer.

CONCLUSIONS

Overall, this study supports the hypothesis of associations of variations of patients' oral microbiota to pancreatic cancer. Nonetheless, due to all included studies were conducted in USA or Europe, additional original studies and meta-analysis particular studies from other countries are essential for an in-depth investigation into the role of oral bacteria in pancreatic cancer.

Atypical enhanced computed tomography signs of pancreatic cancer and its differential diagnosis from autoimmune pancreatitis

Background

To analyze the atypical enhanced computed tomography (CT) signs of pancreatic cancer (PC) and compare them with those of autoimmune pancreatitis (AIP) to explore the differential diagnosis value of CT.

Methods

The clinical data of 36 AIP (AIP group) and 38 PC patients (PC group), who were admitted to our hospital from January 2013 to June 2020 and confirmed by surgical biopsy or hormone therapy, were retrospectively analyzed. Participants in both groups were examined by CT, the imaging signs of the 2 groups were analyzed, and the results of CT examination were compared.

Results

In the PC group, the density of the lesions on the CT scan was mostly reduced, the pancreas was not swollen, and the kidneys were not involved. The bile duct wall was thickened with a sausage-like appearance, enveloped edges were rare, blood vessels were invaded, lymph nodes were enlarged, and the pancreatic duct was truncated. The findings of the AIP group were the opposite. The difference in the proportion of participants with the above-mentioned CT features between the 2 groups was statistically significant (P<0.05). The shape of the lesions in the AIP group was mainly elongated, of uneven density, and the density of enhanced scanning was medium to high. The predominant shape of the lesions in PC participants was spherical, and the density was uniform. The enhanced scan was mainly low-density. The difference in shape and density between the 2 groups was also statistically significant (P<0.05). The CT values of the plain scan, intravenous phase, and delayed phase in the AIP group were significantly higher than those in the PC group (P<0.05).

Conclusions

The imaging signs of AIP and PC overlap. Examination with CT is of great value in the differential diagnosis between AIP and PC. Familiarity with and mastery of the CT signs of AIP and PC can help to improve the accuracy of clinical diagnosis and provide a reliable basis for patients' follow-up treatment.

Diffuse Pancreatic Carcinoma with Hepatic Metastases

Pancreatic cancer is one of the seven leading causes of cancer death worldwide. Diffuse pancreatic carcinoma is very rare and underreported in the literature. Many advances have been made in the diagnosis and management of pancreatic cancer. However, most pancreatic cancer cases are detected at the terminal or metastatic stages. Therefore, timely diagnosis and therapeutic management are desirable goals for this disease. Although the proliferation of pancreatic cancer has been reduced by intervention, more work is needed to treat and prevent the disease. The purpose of this article is to present a case of a 54-year-old male with pancreatic cancer and to review the epidemiology, diagnosis, management, and prevention of pancreatic tumors in general as well as pancreatic carcinoma in particular.

Prevalence of histological features resembling autoimmune pancreatitis in neoplastic pancreas resections

AIMS

Types 1 and 2 autoimmune pancreatitis (AIP) can mimic pancreatic neoplasia. Due to the small quantity of tissue in mass-targeted pancreas biopsies, inflammatory features may raise the differential of AIP. However, the frequency of AIP-like histology in neoplastic pancreas is not well characterised. Therefore, the specificity of inflammatory lesions on biopsy with respect to the diagnosis of AIP is uncertain.

METHODS AND RESULTS

Neoplastic pancreas resections performed at our institution between 2008 and 2019 were retrospectively reviewed. Features of AIP types 1 and 2 were assessed in the non-neoplastic areas. If features of immunoglobulin (Ig)G4-associated AIP were seen, IgG4 immunohistochemistry was performed. We identified 163 neoplastic pancreas resections. Of these, 34 had one or more types of inflammatory lesions in non-neoplastic pancreatic tissue. Dense lymphoplasmacytic inflammation mimicking type 1 AIP was found in six cases with mild to moderately increased IgG4-positive plasma cells. Neutrophilic infiltrates in small intralobular ducts were found in 20 cases. Mild extralobular ductitis or duct microabscess was found in 10 specimens. Marked neutrophilic duct destruction that resembled granulocytic epithelial lesions was found in 12 cases. Some cases showed multiple features.

CONCLUSION

Approximately 20% of neoplastic pancreas resections showed focal areas that could raise the differential of AIP. More cases showed neutrophilic predominant inflammation as seen in type 2 autoimmune pancreatitis, compared to dense lymphoplasmacytic infiltrates seen in type 1 AIP. Pathologists must be cautious when making a diagnosis of AIP on biopsy tissue based on histological findings alone.