Non-neoplastic pancreatic lesions that may mimic malignancy

Misdiagnosis of pancreatic intraductal papillary mucinous neoplasms and the challenge of mimicking lesions: imaging diagnosis and differentiation strategies

The rising prevalence of pancreatic cystic lesions (PCLs), particularly intraductal papillary neoplasms (IPMNs), has been attributed to increased utilization of advanced imaging techniques. Incidental detection of PCLs is frequent in abdominal CT and MRI scans, with IPMNs representing a significant portion of these lesions. Surveillance of IPMNs is recommended due to their malignant potential; however, their overlapping imaging features with benign entities can lead to misdiagnosis, overtreatment, and overutilization of healthcare resources. This paper aims to highlight and differentiate lesions often mistaken for IPMNs, providing insight into their imaging characteristics, diagnostic challenges, and distinctive features while highlighting the incidence of wrong diagnosis for these lesions. These lesions include serous cystadenomas, cystic pancreatic neuroendocrine tumors, mucinous cystic neoplasms, lymphoepithelial cysts, duodenal diverticula, pancreatic schwannomas, chronic pancreatitis, retention cysts, intrapancreatic accessory spleens, pancreatic lipomas, choledochal cysts, and others. Utilizing various imaging modalities, including contrast-enhanced CT, MRI, and EUS, alongside histological and molecular analyses, can aid in accurate diagnosis and appropriate management. Understanding these mimicry scenarios is crucial to avoid unnecessary surveillance, interventions, and the burden they place on both patients and healthcare systems. Improved recognition of these lesions can lead to better patient outcomes and resource allocation.

Large cystic lymphangioma of the pancreas: unusual finding with differential diagnosis and therapeutic considerations

Lymphangiomas are rare benign tumours of lymphatic vascular origin. They are more common in the paediatric population and manifest mainly in the neck and axillary region. Retroperitoneal lymphangiomas are <1% and pancreatic origin is even rarer. We present a case of a pancreatic cystic lymphangioma in a 60-year-old woman with chronic diffuse symptoms, diagnosed because of newly onset of diabetes mellitus. She was successfully managed with distal pancreatectomy and spleenectomy en-bloc with the cystic mass without any complications. Cystic lymphangioma of the pancreas is a rare entity presenting with a challenging preoperative diagnosis as imaging modalities may provide ambiguous information. The clinician should be aware of its complicated differential diagnosis and its persistent and subtle symptomatology.

Rare Solid Pancreatic Lesions on Cross-Sectional Imaging

Several solid lesions can be found within the pancreas mainly arising from the exocrine and endocrine pancreatic tissue. Among all pancreatic malignancies, the most common subtype is pancreatic ductal adenocarcinoma (PDAC), to a point that pancreatic cancer and PDAC are used interchangeably. But, in addition to PDAC, and to the other most common and well-known solid lesions, either related to benign conditions, such as pancreatitis, or not so benign, such as pancreatic neuroendocrine neoplasms (pNENs), there are solid pancreatic lesions considered rare due to their low incidence. These lesions may originate from a cell line with a differentiation other than exocrine/endocrine, such as from the nerve sheath as for pancreatic schwannoma or from mesenchymal cells as for solitary fibrous tumour. These rare solid pancreatic lesions may show a behaviour that ranges in a benign to highly aggressive malignant spectrum. This review includes cases of an intrapancreatic accessory spleen, pancreatic tuberculosis, solid serous cystadenoma, solid pseudopapillary tumour, pancreatic schwannoma, purely intraductal neuroendocrine tumour, pancreatic fibrous solitary tumour, acinar cell carcinoma, undifferentiated carcinoma with osteoclastic-like giant cells, adenosquamous carcinoma, colloid carcinoma of the pancreas, primary leiomyosarcoma of the pancreas, primary and secondary pancreatic lymphoma and metastases within the pancreas. Therefore, it is important to determine the correct diagnosis to ensure optimal patient management. Because of their rarity, their existence is less well known and, when depicted, in most cases incidentally, the correct diagnosis remains challenging. However, there are some typical imaging features present on cross-sectional imaging modalities that, taken into account with the clinical and biological context, contribute substantially to achieve the correct diagnosis.

A high serum creatine kinase (CK)-MB-to-total-CK ratio in patients with pancreatic cancer: a novel application of a traditional marker in predicting malignancy of pancreatic masses?

BACKGROUND

The finding that some benign pancreatic masses mimic the imaging appearance of carcinomas poses a challenge for pancreatic surgeons. Preoperative markers that assist in the diagnosis are critical under this circumstance. Abnormal serum creatine kinase (CK) isozyme levels were reported in cancer patients, and this study aimed to explore the potential value of the CK-MB-to-total-CK ratio (CK ratio) in differentiating pancreatic cancer (PC) from benign masses when combined with carbohydrate antigen 19-9 (CA19-9).

METHODS

A total of 190 patients primarily diagnosed with pancreatic masses were retrospectively reviewed and assigned to the PC group and the benign pancreatic mass (BPM) group. Sixty-eight controls were enrolled for comparison. Levels of preoperative parameters, including total serum CK, CK-MB, absolute neutrophil count, absolute lymphocyte count, albumin, and CA19-9, were recorded as well as pathological information. A logistic regression model was established to assess the application value of the combination of CA19-9 and the CK ratio in diagnosis. Receiver operating characteristic (ROC) curves were constructed to evaluate the diagnostic value of the markers.

RESULTS

The CK ratio was significantly elevated in the PC group compared with the BPM group (P < 0.001). In the multivariate analysis, a CK ratio greater than 0.220 was a statistically significant variable for predicting malignancy of pancreatic masses (P=0.001). Patients with stage III/IV PC had a higher CK ratio than those with stage I/II PC (P<0.01). Combined detection of CA19-9 and the CK ratio produced an increased Youden index (0.739 vs. 0.815) with improved sensitivity (82.2% vs. 89.8%).

CONCLUSIONS

The CK ratio is elevated in patients with pancreatic adenocarcinoma and is an independent factor predicting pancreatic adenocarcinoma. The CK ratio augments the diagnostic capacity of CA19-9 in detecting malignancy.

Cystic lymphangioma of the pancreatic head treated by enucleation: Case report and literature review

Introduction

The widespread use of imaging methods has led to an increased identification of asymptomatic Pancreatic Cystic Lymphangiomas (PCL), a rare entity for which available information is very limited.

Presentation of case

We present the case of an asymptomatic 61-year-old male, submitted to elective enucleation of a pancreatic head PCL at our institution. After four years of follow-up the patient is doing well and has no clinical or imaging signs of recurrence.

Discussion

Though rare, PCL should be included in the differential diagnosis of pancreatic cystic neoplasms. All efforts should be made to ascertain a preoperative diagnosis, as expectant follow-up could be a reasonable approach in asymptomatic patients and/or poor surgical candidates. In the face of an uncertain diagnosis, complete surgical excision may be the treatment of choice.

Conclusion

The medical community worldwide should be encouraged to report all cases of PCL, as to increment the overall knowledge about this lesion.

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Widespread use of cross-sectional imaging increased identification of asymptomatic pancreatic cystic lesions.

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Pancreatic Cystic Lymphangioma is one of those rare cystic neoplasms for which available information is very limited.

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Definitive diagnosis often requires pathologic examination of surgical specimen, immunohistochemically with positivity for D2-40.

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En bloc resection with negative margins is curative, however, treatment for asymptomatic cystic lymphangiomas is still controversial.

Pseudotumoral Lesion as a Manifestation of Autoimmune Pancreatitis

Autoimmune pancreatitis is a chronic and benign disease of autoimmune etiology that can occur isolated or constitute a manifestation of immunoglobulin G4 (IgG4)-related disease (types 2 and 1, respectively). It is a pathological condition that can mimic pancreatic cancer by presenting as a mass in imaging studies and provoking symptoms such as obstructive jaundice and dramatic weight-loss. The inflammatory infiltrates in the pancreas can also produce endocrine dysfunction leading to diabetes. The authors report the case of a 68-year-old man that presented with unexplained weight loss and poorly controlled diabetes despite progressive pharmacological adjustments, with a later onset of obstructive jaundice, for which he underwent pancreaticoduodenectomy with the pre-operative diagnosis of pancreatic malignant neoplasm, which was posteriorly identified as type 1 autoimmune pancreatitis. In these cases, the differential diagnosis might be particularly challenging, requiring a high level of suspicion to avoid unnecessary procedures. Corticosteroid therapy can lead to the resolution of symptoms as well as glycemic control, and it is the cornerstone of IgG4-related disease treatment. However, corticosteroid-sparing agents may be of interest to achieve clinical suppression.

Laparoscopic spleen-preserving pancreatic resection for intrapancreatic accessory spleen: Case report

INTRODUCTION

Intrapancreatic accessory spleen (IPAS) has been rarely noted radiologically because the spatial resolution of conventional images was low. The infrequent presence of the accessory spleen in the pancreatic tissue could lead to inappropriate diagnosis, thereby necessitating a therapeutic approach. The present study reported such cases and summarized the available imaging findings to reduce unnecessary invasive surgeries.

PATIENT CONCERNS

The patient's complaint was "a pancreatic mass was found for half a month."

DIAGNOSIS

IPAS was eventually diagnosed by pathology.

INTERVENTIONS

Laparoscopic spleen-preserving pancreatic resection.

OUTCOMES

Postoperative course was uneventful and the patient was discharged from our hospital after 10 days.

CONCLUSIONS

When an asymptomatic pancreatic mass is detected, the diagnosis of IPAS should not be excluded, especially if the lesion has the same imaging features as the spleen. As a definite diagnosis of IPAS is difficult by a single examination, multiple techniques might be essential.

Usefulness of non-contrast MR imaging in distinguishing pancreatic ductal adenocarcinoma from focal pancreatitis

BACKGROUND

Accurate differentiation between pancreatic adenocarcinoma and focal pancreatitis is challenging.

PURPOSE

To investigate the usefulness of non-contrast MRI by comparing with multidetector row CT (MDCT) and gadoxetic acid-enhanced MRI in the discrimination of pancreatic ductal adenocarcinoma (PDAC) and focal pancreatitis (FP).

MATERIALS AND METHODS

This retrospective study included 187 patients (116 with PDACs and 71 with FP) who underwent gadoxetic acid-MRI and MDCT prior to surgical resection or biopsy. The MRI features of PDAC and FP were compared by two radiologists. Then, two observers independently reviewed the three imaging sets: MDCT, non-contrast MRI (T1-, T2-weighted, and diffusion-weighted images), and MRI with and without gadoxetic acid to determine the diagnostic performances of each imaging modality in the discrimination of PDAC and FP.

RESULTS

The significant features on non-contrast MRI for diagnosis of PDAC included peritumoral cyst, pancreatic duct cut-off, clear hypointensity on T1WI, and bile duct dilatation (P < 0.05). Presence of peritumoural cyst showed the highest odds ratio for predicting PDAC. Non-contrast MRI was superior to MDCT in differentiating PDAC from FP with regard to accuracy (84.5% vs 95.5% for observer 1; 85.8% vs. 96.0% for observer 2), sensitivity (83.6% vs. 98.3%; 84.5% vs 97.8%), and negative predictive value (76.3% vs. 97.0%; 77.6% vs 96.4%) (P < 0.05). We found similar diagnostic values between the non-contrast MRI and MRI with and without contrast (P > 0.05) for both observers.

CONCLUSION

Non-contrast MRI is better than MDCT and comparable to MRI with and without gadoxetic acid in differentiating PDAC from FP.

Cystic lymphangioma of the pancreas: a hard diagnostic challenge between pancreatic cystic lesions-review of recent literature

Lymphangiomas are rare congenital benign tumors arising from the lymphatic system. The incidence of this disease in the pancreas is extremely rare, accounting for less than 1% of these tumors. Before introducing the review we reported a case of a 67-year-old woman with cystic lymphangioma of the pancreas. We reported the radiological investigations carried out preoperatively and the treatment performed. The review tries to identify the features described in literature of the pancreatic lymphangioma. We have performed a PubMed research of the world literature between January 1^st 2000, to November 31^st 2017, using the keywords [Lymphangioma pancreas], [diagnosis], [CT lymphangioma] and [MRI lymphangioma]. We have found 158 articles, of which about 100 were case reports. Based on our search criteria, we have identified 31 pancreatic lymphangioma in literature reporting their imaging characteristics. According to our report and to several authors in literature the diagnosis of cystic pancreatic lymphangioma should be considered as a differential diagnosis of pancreatic cystic lesions (PCLs). The role of imaging exams (CT and MRI) can help to identify and suspect this possibility of diagnosis. The endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) can have a potential role to reach the correct diagnosis.

Benign Tumors and Tumorlike Lesions of the Pancreas

The pancreas is a complex organ that may give rise to large number of neoplasms and non-neoplastic lesions. This article focuses on benign neoplasms, such as serous neoplasms, and tumorlike (pseudotumoral) lesions that may be mistaken for neoplasm not only by clinicians and radiologists, but also by pathologists. The family of pancreatic pseudotumors, by a loosely defined conception of that term, includes a variety of lesions including heterotopia, hamartoma, and lipomatous pseudohypertrophy. Autoimmune pancreatitis and paraduodenal ("groove") pancreatitis may also lead to pseudotumor formation. Knowledge of these entities will help in making an accurate diagnosis.

Natural history of intraductal papillary mucinous neoplasm and non-neoplastic cyst: long-term imaging follow-up study

BACKGROUND

To identify differences in incidence and mortality of pancreatic cancer (PC) between intraductal papillary mucinous neoplasm (IPMN) and non-neoplastic cyst.

METHODS

Patients with pancreatic cyst (n = 526; 263 with IPMN and 263 with non-neoplastic cyst matched for age, sex, and diagnosis year) were periodically followed-up with imaging. Hazard ratio (HR), standardized incidence ratio (SIR), and standardized mortality ratio (SMR) for PC and PC-related mortality were estimated.

RESULTS

During a mean follow-up of 57.5 months with 3,376 computed tomography scans and 1,079 magnetic resonance imaging scans, 5-year cumulative PC incidence was 4.0% for IPMN and 0% for non-neoplastic cyst, respectively (HR 5.2; P = 0.031). During a mean follow-up of 73.1 months, 5-year cumulative PC-related mortality was 2.6% for IPMN and 0% for non-neoplastic cyst, respectively (HR 4.5; P = 0.05). Compared with the general population in Japan, patients with IPMN, but not those with non-neoplastic cyst, had significantly increased risks of PC incidence (SIR 22.03) and related mortality (SMR 15.9).

CONCLUSIONS

During long-term imaging follow-up, patients with IPMN developed PC over time, whereas none of the patients with non-neoplastic cyst developed it within 5 years. Compared with the general population, patients with IPMN, but not those with non-neoplastic cyst, were at risk of PC and related mortality.

Primary Leiomyosarcoma of the Pancreas-a Case Report and a Comprehensive Review

Purpose

Primary mesenchymal tumors of the pancreas are rare, with leiomyosarcomas the most encountered entities among the pancreatic sarcomas. With few exceptions, single case reports published over the last six decades constitute the entire scientific literature on this topic. Thus, evidence regarding clinical decision-making is scant.

Methods

Based on a case report and an extensive literature search in PubMed, we discuss the clinical aspects and current management of this rare malignancy.

Results

We identified only two papers with more than a single case presentation; these institutional patient series were limited to five and nine patients. Additionally, a few papers sought to summarize the individual case reports published in the English and/or Chinese language. The clinical presentation is rather non-specific. Moreover, modern imaging modalities are insufficiently accurate to diagnose leiomyosarcoma of the pancreas. Treatment goals include a complete resection with free margins. Proper morphologic examination using immunohistochemistry and the application of a grading system are clinically important for prognostication. The efficacy of adjuvant treatments has not been established.

Conclusion

Primary pancreatic leiomyosarcoma is extremely rare, and the scientific literature is primarily based on single case reports. Conclusions on management and prognosis should be drawn with caution. A multidisciplinary team consultation is warranted to discuss a thorough individual treatment plan based on the available scientific literature, despite its low evidence level.

Intrapancreatic Accessory Spleen: A Diagnosis Not to Forget!

A 69-year-old male patient was incidentally diagnosed with a 5-mm lesion in the pancreatic tail by endoscopic ultrasound (EUS). After contrast-enhanced EUS and EUS-elastography, all imaging features were highly suggestive of a benign pancreatic solid lesion such as an intrapancreatic accessory spleen (IPAS) or a benign neuroendocrine tumor. Interposition of the splenic artery precluded EUS-guided fine-needle aspiration (FNA). When an asymptomatic pancreatic mass is detected, IPAS diagnosis should be considered, and, if EUS-FNA is infeasible, contrast-enhanced EUS and EUS-elastography are useful tools to differentiate a pancreatic benign lesion as IPAS from a malignancy, with avoidance of unnecessary surgery.