Uncommon pancreatic tumors and pseudotumors

Hidden in plain sight: commonly missed early signs of pancreatic cancer on CT

Pancreatic ductal adenocarcinoma (PDAC) has poor prognosis mostly due to the advanced stage at which disease is diagnosed. Early detection of disease at a resectable stage is, therefore, critical for improving outcomes of patients. Prior studies have demonstrated that pancreatic abnormalities may be detected on CT in up to 38% of CT studies 5 years before clinical diagnosis of PDAC. In this review, we highlight commonly missed signs of early PDAC on CT. Broadly, these commonly missed signs consist of small isoattenuating PDAC without contour deformity, isolated pancreatic duct dilatation and cutoff, focal pancreatic enhancement and focal parenchymal atrophy, pancreatitis with underlying PDAC, and vascular encasement. Through providing commentary on demonstrative examples of these signs, we demonstrate how to reduce the risk of missing or misinterpreting radiological features of early PDAC.

Case report: Immunotherapy in rare high TMB pancreatic acinar carcinoma

This case report details a patient with Pancreatic Acinar Cell Carcinoma (PACC), a rare malignancy with distinctive biological and imaging features. In the absence of standardized treatment protocols for PACC, we embarked on a diagnostic journey that led to the adoption of an innovative therapeutic regimen in our institution. A 45-year-old female patient presented with a pancreatic mass, which was histologically confirmed as PACC following a biopsy. Subsequent genomic profiling revealed a high tumor mutational burden (21.4/Mb), prompting the initiation of combined immunotherapy and targeted therapy. Notably, the patient experienced a unique adverse reaction to the immunotherapy-recurrent subcutaneous soft tissue nodules, particularly in the gluteal and lower limb regions, accompanied by pain, yet resolving spontaneously. Following six cycles of the dual therapy, radiological evaluations indicated a decrease in tumor size, leading to a successful surgical excision. Over a 20-month post-surgical follow-up, the patient showed no signs of disease recurrence. This narrative adds to the existing knowledge on PACC and highlights the potential efficacy of immunotherapy in managing this challenging condition, emphasizing the importance of close monitoring for any adverse reactions.

IgG4-related inflammatory pancreatic head pseudotumor mirrors pancreatic head tumor: A novel case series with a review of the literature

Key Clinical Message

In this noteworthy case series regarding pancreatic pseudo tumors, we intend to spread knowledge among physicians for the diagnostic and therapeutic approach and eventual disease prognosis.

Abstract

Inflammatory pseudotumor of pancreatic head greatly mimics pancreatic head tumor. One of them is IgG4-related pancreatic disease, which is commonly mistaken as neoplastic disease on imaging. In our novel case series, we report three cases of IgG4-related pancreatic head pseudotumor with patients ranging from 35 to 72 years of age. Patients presented with jaundice and abdominal pain. Alongside initial laboratory workup, abdominal CTs and serum IgG4 levels were also obtained. Imaging features in conjunction with IgG4 levels confirmed the diagnosis of IgG4-related autoimmune pancreatitis. Pancreatic pseudotumors are notorious for being often reported as real tumors. Through our noteworthy case series, we intend to highlight the imaging features and laboratory markers that are crucial in such cases to avoid invasive procedures.

Can solid pseudopapillary neoplasm of the pancreas without degeneration be diagnosed with imaging? a comparison study of the solid component of solid pseudopapillary neoplasm, neuroendocrine neoplasm, and ductal adenocarcinoma

PURPOSE

To investigate the MR findings of the solid components within pancreatic solid pseudopapillary neoplasms (SPNs) to characterize solid SPN without degeneration.

METHODS

After case matching, 23 patients with SPNs, 23 with pancreatic neuroendocrine neoplasms (PNENs), and 46 pancreatic ductal adenocarcinomas (PDACs) were included in this retrospective comparative study. The MR findings of the solid components within the pancreatic tumors were assessed qualitatively and semi-quantitatively.

RESULTS

In the qualitative assessment, significant differences were noted in T2-weighted imaging and MR cholangiopancreatography (MRCP). SPNs with a score of 4-5 (iso- to hyper-intense compared with the renal cortex) were observed in 18/19 (94.7%) by reader 1 and 15/19 (78.9%) by reader 2 (score 5, 52.6% and 47.4%) on fast spin-echo (FSE) T2-weighted imaging. On MRCP, the two readers identified 12 (63.2%) and 8 (42.1%) SPNs, respectively. The semi-quantitative signal-intensity ratio (SIR, signal intensity of tumor/signal intensity of the pancreatic parenchyma) of SPNs on FSE T2-weighted imaging was significantly higher (mean, 1.99-2.01) than that of PNENs (1.30-1.31) or PDACs (1.26-1.28). The sensitivity/specificity of 'hyper' on T2-weighted imaging (qualitative score of 4-5, or SIR of ≥ 1.5) were 78.9-100.0%/63.8-79.7%. The sensitivity/specificity of 'remarkably hyper' (score of 5, SIR of ≥ 2.0, or visible on MRCP) or salt-and-pepper pattern were 36.8-68.4%/85.5-98.6%.

CONCLUSION

T2-weighted imaging may be the key sequence for solid SPN. Solid tumors with hyper-intensity on T2-weighted imaging (especially, more hyper-intense than the renal cortex, more than twice the signal of the pancreatic parenchyma, depicted on MRCP, or salt-and-pepper appearance) may be suspected to be SPNs.

Pancreatic acinar cell carcinoma: A comprehensive review

Acinar cell carcinoma (ACC) is a rare pancreatic malignancy with distinctive clinical, molecular, and morphological features. The long-term survival of ACC patients is substantially superior to that of pancreatic adenocarcinoma patients. As there are no significant patient series about ACCs, our understanding of this illness is mainly based on case reports and limited patient series. Surgical resection is the treatment of choice for patients with the disease restricted to one organ; however, with recent breakthroughs in precision medicine, medicines targeting the one-of-a-kind molecular profile of ACC are on the horizon. There are no standard treatment protocols available for people in which a total surgical resection to cure the condition is not possible. As a result of shared genetic alterations, ACCs are chemosensitive to agents with activity against pancreatic adenocarcinomas and colorectal carcinomas. The role of neoadjuvant or adjuvant chemoradiotherapy has not been established. This article aims to do a comprehensive literature study and present the most recent information on acinar cell cancer.

Immunoglobulin G4-Negative Inflammatory Pseudotumors of the Pancreas

Inflammatory pseudotumor (IPT) can occur in any organ, but rarely shows pancreatic involvement. While surgical excision has been recommended as the primary treatment for IPT of the pancreas in the past, some authors suggest observation while medical management often results in regression. Corticosteroids, nonsteroidal anti-inflammatory drugs and immunosuppressive therapy have been used to treat IPTs. Spontaneous regression has also been reported in IPT managed without surgical intervention. A 62-year-old female was evaluated for worsening abdominal pain and a mass in the neck of the pancreas that was identified on ultrasound. Further imaging with magnetic resonance imaging revealed a pancreatic mass with dilated pancreatic duct and an atrophic parenchyma of the pancreatic neck. Her serum tumor markers were not elevated. As this lesion appeared to be resectable pancreatic cancer based on cross-sectional imaging, no biopsy was performed prior to surgical resection. Distal pancreatectomy and splenectomy was recommended and the patient desired to proceed. Her recovery was uneventful with no postoperative complications, including pancreatic fistula. Final pathology revealed a lesion consistent with the diagnosis of immunoglobulin G4 (IgG4)-negative IPT without neoplasm. IPT of the pancreas is a difficult entity to diagnose and treat due to clinical and imaging characteristics closely resembling pancreatic adenocarcinoma. Biopsy with immunohistochemical analysis can be useful in diagnosing IPT; however, symptomatic lesions and concerning findings on cross-sectional imaging may warrant more definitive surgical intervention.

Role of endoscopic ultrasound elastography in differential diagnosis of pancreatic solid masses

Introduction: Endoscopic ultrasound (EUS) elastography is another technique that measures the stiffness of tissue and adds more diagnostic value to EUS.

Objective: This study aimed to assess the ability of qualitative and quantitative EUS elastography in differentiating malignant from benign solid pancreatic masses.

Methods: This 2-year cross-sectional study enrolled 80 patients with solid pancreatic masses in the department of endoscopy in Alassad University Hospital who underwent conventional and elastography-assisted EUS and then followed for pathology through EUS-guided or CT-guided biopsy or surgery.

Results: Qualitative elastography using a 5-point scoring system was able to recognize malignant pathology (obtained by EUS-guided biopsy, CT-guided biopsy, or surgery) with a sensitivity, specificity, and accuracy rates of 100%, 28.6%, and 81.3%, respectively. A quantitative method using hue histogram had a sensitivity of 71.2%–86.4% and specificity of 71.4%–81% with the best accuracy for histogram mean ratio (area under the curve, 0.867).

Conclusion: EUS elastography is a simple and good alternative method in differentiating malignant from benign pancreatic solid masses.

An intrapancreatic bronchogenic cyst simulating a mucinous cystadenoma. A case report

We present the case of a 61-year-old male with a long-term epigastric mass and pain, high CA 19.9 levels and no weight loss. A computerized tomography was performed and a solid-cystic pancreatic mass was observed. The lesion measured 10 x 8 cm with well-defined margins, a macroscopic calcification and an enhanced solid component.

Chronic Pancreatitis or Pancreatic Tumor? A Problem-solving Approach

Certain inflammatory pancreatic abnormalities may mimic pancreatic ductal adenocarcinoma at imaging, which precludes accurate preoperative diagnosis and may lead to unnecessary surgery. Inflammatory conditions that may appear masslike include mass-forming chronic pancreatitis, focal autoimmune pancreatitis, and paraduodenal pancreatitis or "groove pancreatitis." In addition, obstructive chronic pancreatitis can mimic an obstructing ampullary mass or main duct intraductal papillary mucinous neoplasm. Secondary imaging features such as the duct-penetrating sign, biliary or main pancreatic duct skip strictures, a capsulelike rim, the pancreatic duct-to-parenchyma ratio, displaced calcifications in patients with chronic calcific pancreatitis, the "double duct" sign, and vessel encasement or displacement can help to suggest the possibility of an inflammatory mass or a neoplastic process. An awareness of the secondary signs that favor a diagnosis of malignant or inflammatory lesions in the pancreas can help the radiologist to perform the differential diagnosis and determine the degree of suspicion for malignancy. Repeat biopsy or surgical resection may be necessary to achieve an accurate diagnosis and prevent unnecessary surgery for inflammatory conditions. Online supplemental material and DICOM image stacks are available for this article. ^©RSNA, 2019.

Inflammatory Pseudotumor of the Pancreas Mimicking a Pancreatic Neoplasm

A 78-year-old woman was admitted to our hospital with a pancreatic tumor, incidentally discovered in an abdominal ultrasound exam. She was asymptomatic and without any previous personal pathological condition. The computed tomography (CT) and the magnetic resonance imaging (MRI) scan showed a mass lesion of 4 cm in diameter, located in the pancreatic body, conditioning the invasion of the splenic vein. The patient was admitted to surgery. During the laparotomy, we found a tumoral lesion highly suspicious of pancreatic neoplasia located in the transition of the head/body of the pancreas, with an invasion of the portal vein and several peri-regional lymph nodes. We performed biopsies of the pancreatic mass and lymphadenectomy of the peri-regional pancreatic lymph nodes. Histological analysis found an inflammatory pseudotumor of the head/body of the pancreas, without signals of malign epithelial neoplasm and also without criteria for immunoglobulin G4-related disease. During the follow-up, a PET/CT and MRI confirmed that the pancreatic lesion had disappeared without any treatment. Inflammatory pseudotumor of the pancreas is a rare entity not fully understood. Despite this, the administration of corticosteroids and immunosuppressive therapy could be taken into consideration as the disease carries a risk.

Comparison of Navigator Triggering Reduced Field of View and Large Field of View Diffusion-Weighted Imaging of the Pancreas

RATIONALE AND OBJECTIVES

The purpose of this study is to compare image quality, presence and grade of artifacts, signal-to-noise ratio, and apparent diffusion coefficient (ADC) values in pancreatic tissue between high-resolution navigator-triggered (NT) restricted field of view (rFOV) FOCUS single-shot (SS) echo-planar imaging (EPI) diffusion-weighted imaging (DWI) and NT large FOV SS-EPI DWI.

MATERIALS AND METHODS

Magnetic resonance imaging examinations were performed with GE 3-T systems using a 32-channel body array coil. Seventeen consecutive patients were imaged. A 5-point scale semiquantitative grading system was used to evaluate image quality and general artifacts. Signal-to-noise ratio and ADC were measured in the head, body, and tail of the pancreas. Statistical analysis was performed using Student t test and Wilcoxon signed rank test, with differences considered significant for P value less than 0.05.

RESULTS

More artifacts were present on large FOV compared with rFOV FOCUS SS-EPI DW images (P < 0.01). Restricted field of view image quality was subjectively better (P < 0.01). No difference in the signal-to-noise ratio was demonstrated between the 2 image datasets. Apparent diffusion coefficient values were significantly lower (P < 0.01) when calculated from rFOV images than large FOV images.

CONCLUSIONS

Our results demonstrate better image quality and reduced artifacts in rFOV images compared with large FOV DWI. Measurements from ADC maps derived from rFOV DWI show significantly lower ADC values when compared with ADC maps derived from large FOV DWI.

Intravoxel incoherent motion diffusion-weighted MR imaging of solid pancreatic masses: reliability and usefulness for characterization

PURPOSE

IVIM-DW imaging has shown potential usefulness in the study of pancreatic lesions. Controversial results are available regarding the reliability of the measurements of IVIM-derived parameters. The aim of this study was to evaluate the reliability and the diagnostic potential of IVIM-derived parameters in differentiation among focal solid pancreatic lesions and normal pancreas (NP).

METHODS

Fifty-seven patients (34 carcinomas-PDACs, 18 neuroendocrine neoplasms-panNENs, and 5 autoimmune pancreatitis-AIP) and 50 subjects with NP underwent 1.5-T MR imaging including IVIM-DWI. Images were analyzed by two independent readers. Apparent diffusion coefficient (ADC), slow component of diffusion (D), incoherent microcirculation (Dp), and perfusion fraction (f) were calculated. Interobserver reliability was assessed with intraclass correlation coefficient (ICC). A Kruskal-Wallis H test with Steel-Dwass post hoc test was used for comparison. The diagnostic performance of each parameter was evaluated through receiver operating characteristic (ROC) curve analysis.

RESULTS

Overall interobserver agreement was excellent (ICC = 0.860, 0.937, 0.968, and 0.983 for ADC, D, Dp, and f). D, Dp, and f significantly differed among PDACs and panNENs (p = 0.002, < 0.001, and < 0.001), albeit without significant difference at the pairwise comparison of ROC curves (p = 0.08-0.74). Perfusion fraction was higher in AIP compared with PDACs (p = 0.024; AUC = 0.735). Dp and f were higher in panNENs compared with AIP (p = 0.029 and 0.023), without differences at ROC analysis (p = 0.07).

CONCLUSIONS

IVIM-derived parameters have excellent reliability and could help in differentiation among solid pancreatic lesions and NP.

Knife wielding radiologist: A case report of primary pancreatic lymphoma

Majority of malignant pancreatic neoplasms are epithelial in origin and mostly arise from exocrine gland. Ductal adenocarcinoma compromises the major histological type of such tumors. Primary non-epithelial tumors of exocrine pancreatic gland are extremely rare and incorporate lymphoma and sarcoma. Primary pancreatic lymphoma compromises less than 0.5% of pancreatic malignancies. Primary pancreatic lymphoma can be difficult to differentiate from pancreatic adenocarcinoma and other neoplasms on imaging, and a correct diagnosis is crucial for appropriate patient management.

Multiple solid pancreatic lesions: Prevalence and features of non-malignancies on dynamic enhanced CT

OBJECTIVE

To determine the prevalence of multiple solid pancreatic lesions on dynamic enhanced CT performed for suspected pancreatic diseases, and to identify CT features of non-malignancies.

METHODS

We investigated 8096 consecutive patients who underwent dynamic enhanced CT pancreas protocol at a tertiary center over 40 months. The final clinical /pathological diagnosis served as reference standard. The diagnostic accuracy of dynamic enhanced CT for non-malignancies was calculated. A univariate and multivariate analysis was conducted to identify features that predict non-malignancies.

RESULTS

Multiple solid pancreatic lesions were identified in 121 patients. The prevalence of non-malignancies was 19.8% (24/121). The most common non-malignancy was autoimmune pancreatitis (n = 21; 17.4%). Common lesions with malignant potential included neuroendocrine neoplasia (n = 62; 51.2%), ductal adenocarcinoma (n = 15; 12.4%), metastasis (n = 9; 7.4%), and lymphoma (n = 7; 5.8%). Dynamic enhanced CT had a sensitivity of 79.2% and a specificity of 92.8% for diagnosing non-malignancies. Elevated serum IgG4 level (p < 0.001), hypo-enhancement in arterial phase (p = 0.001), hyper-enhancement in equilibrium phase (p = 0.009) and location in both proximal and distal pancreas (p = 0.036) were predictors of non-malignancies, whereas pancreatic duct morphology and vascular invasion status were not.

CONCLUSION

Multiple solid pancreatic lesions were rare, with a wide spectrum. Dynamic enhanced CT provides clues for identifying non-malignancies.

Hepatobiliary and Pancreatic: Primary acinar cell carcinoma of the liver showing good response to chemotherapy

A 48-year old man with no history of liver disease or alcohol addiction developed jaundice, itching and dark urine without any symptom of abdominal pain.

A CT examination revealed the presence of a liver mass extending between segments 4, 5 and 8 that was found to be an acinar cell carcinoma at biopsy. The primary hepatic origin was confirmed mainly excluding a primary pancreatic tumor by diagnostic work-up.

Since the lesion was considered unresectable at the time of the diagnosis, the patient underwent to Xeloda and oxaliplatin neoadjuvant chemotherapy, with progressive reduction in size of the mass as a sign of good response to therapy.

Pancreatoblastoma With Metastatic Retroperitoneal Lymph Node and PET/CT

A previously healthy 4-year-old girl presented with petechial rash and low platelet count. There were no other symptoms. On abdominal ultrasound, a 4.7-cm heterogeneous mass was demonstrated anterior to the left kidney. An abdominal MRI subsequently performed demonstrated a heterogeneously enhancing mass at the same location extending to the pancreas and spleen. A surgical biopsy of the mass was obtained. Pathology reported a malignant epithelioid neoplasm consistent with pancreatoblastoma. The mass demonstrated intense FDG uptake on PET and an FDG avid retrocaval lymph node.

Imaging features of malignant abdominal neuroendocrine tumors with rare presentation

BACKGROUND

Gastroenteropancreatic neuroendocrine tumors (NETs) are rare entities arising from neuroendocrine cells in the gastroenteric tract and pancreas. The purpose of this article is to present four cases of gastroenteropancreatic NETs that featured a challenging diagnosis.

CASE PRESENTATION

We report a case series of four NETs, each with different features. All NETs were suspected based on clinical and biochemical data. The workup of the abnormalities was performed with CT, PET or MRI.

CONCLUSION

The diagnosis of NETs is challenging and generally based on clinical manifestations, blood biochemical tests, imaging techniques, and pathology.

Malignant transformation of glucagonoma with SPECT/CT In-111 OctreoScan features: A case report

RATIONALE

Glucagonoma is an uncommon disease but it has been associated with a pattern of symptoms defined as glucagonoma syndrome. These symptoms, if promptly recognized, could help to speed up the diagnosing process.

PATIENT CONCERNS

We report a case of a 68-year-old woman with a pancreatic glucagonoma. Her symptoms at the onset were typical of the glucagonoma syndrome.

DIAGNOSES

After a significant weight loss, she underwent a computer tomography scan of the abdomen, which showed a hypervascular lesion of the tail of the pancreas and hypervascular lesions of the liver. An ultrasound guided biopsy was performed and pathology was consistent with glucagonoma. Her blood glucagon levels were elevated.

OUTCOMES

She was treated with chemotherapy and somatostatin analogs. After 4 years, the disease had a malignant transformation, and metastases suddenly started to grow up. She stopped being responsive to treatment and eventually passed away.

LESSONS

Due to its rarity, clinical diagnosis is challenging and generally it comes after a long interval since the onset of symptoms. Awareness of physicians and dermatologists of the characteristic necrolytic migratory erythema, and of the other symptoms, often leads to early diagnosis.

Advances in diffusion-weighted imaging

Diffusion-weighted imaging (DWI) has become a routine component of clinical MR imaging. Its unique soft tissue contrast mechanism exploits differences in the motion of water molecules in vivo at a biologically meaningful scale. The clinical potential of DWI in lesion detection, characterization, and response assessment has been explored. This review briefly covers basic principles of DWI and introduces advances, specifically for abdominopelvic organs.