Endoscopic ultrasound characteristics of pancreatic lymphoepithelial cysts: A case series from a large referral center

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.

Lymphoepithelial cysts of the pancreas: case report and review of the literature

BACKGROUND

Lymphoepithelial cysts (LECs) of the pancreas are a rare type of true pancreatic cysts and represent an estimated 0.5% of all pancreatic cystic lesions. They are benign lesions and have no malignant potential. However, they are hard to differentiate from malignant lesions because their imaging and clinical presentation vary greatly. Seeing as these are benign lesions which are increasingly found incidentally during imaging for other indications, correct diagnosis is important to prevent unnecessary intervention and morbidity.

CASE REPORT

We report the case of a 41-year-old female who presented with abdominal discomfort, bloating and dyspepsia. An abdominal computed tomography (CT) showed a large mass in the left fossa. We describe the diagnostic and therapeutic measures taken in this case.

METHODS

We reviewed the literature for common features of the LEC. We grouped common imaging and histological features of the LEC of the pancreas to provide easily identifiable characteristics to facilitate diagnosis. For the review, we focused on papers, mostly case reports, presenting these common characteristics. We also reviewed the literature for key topics that should be taken into account when considering therapeutic interventions in a patient with a possible diagnosis of a LEC.

CONCLUSION

Cysts of the pancreas are increasingly identified due to widespread use and improved resolution of cross-sectional imaging. To obtain the correct diagnosis, it is sometimes necessary to combine advanced imaging, i.e. CT and MRI-imaging, and endoscopic ultrasound with fine needle aspiration (EUS/FNA), while CA 19-9 also has diagnostic value. We summarize all diagnostic characteristics in a table for ease of use. Furthermore we summarized possible therapeutic interventions.

The Role of Magnetic Resonance Imaging (MRI) in the Diagnosis of Pancreatic Cystic Lesions (PCLs)

Pancreatic cystic lesions (PCLs) are a common incidental finding on cross-sectional imaging. Given the high signal to noise and contrast resolution, multi-parametric capability and lack of ionizing radiation, magnetic resonance imaging (MRI) has become the non-invasive method of choice to predict cyst type, risk stratify the presence of neoplasia, and monitor changes during surveillance. In many patients with PCLs, the combination of MRI and the patient's history and demographics will suffice to stratify lesions and guide treatment decisions. In other patients, especially those with worrisome or high-risk features, a multimodal diagnostic approach that includes endoscopic ultrasound (EUS) with fluid analysis, digital pathomics, and/or molecular analysis is often necessary to decide on management options. The application of radiomics and artificial intelligence in MRI may improve the ability to non-invasively stratify PCLs and better guide treatment decisions. This review will summarize the evidence on the evolution of MRI for PCLs, the prevalence of PCLs using MRI, and the MRI features to diagnose specific PCL types and early malignancy. We will also describe topics such as the utility of gadolinium and secretin in MRIs of PCLs, the limitations of MRI for PCLs, and future directions.

Imaging features and pathological evaluation by EUS-FNA enable conservative management in patient of lymphoepithelial cyst of the pancreas: a case report

Pancreatic lymphoepithelial cysts (LECs) are rare cystic lesions filled with a keratinous substance and lined by squamous epithelium with underlying lymphoid tissue. Because pancreatic LECs are entirely benign, correct preoperative diagnosis is important to avoid unnecessary surgery. However, the imaging features of pancreatic LECs are not specific and preoperative diagnosis has proven difficult. A pancreatic mass was incidentally detected through abdominal ultrasonography in a 63-year-old male presenting without any symptoms. Computed tomography showed an exophytic cystic lesion in the pancreatic head. The lesion had heterogeneous high signal intensity with partial low intensity on T2-weighted magnetic resonance imaging (MRI) and high signal intensity on diffusion MRI. Endoscopic ultrasound (EUS) examination showed an encapsulated cystic lesion with relatively homogenous and highly echoic contents. EUS-guided fine-needle aspiration (EUS-FNA) revealed caseous appearance and rare fragments of apparently benign squamous epithelium on a background of keratinous debris, cyst contents, and scattered lymphocytes. We diagnosed a pancreatic LEC and opted for conservative management without surgery. Pathological evaluation based on images obtained through EUS-FNA showed macro- and microscopic features that were critical to determining the management strategy. In conclusion, the imaging and pathological features of pancreatic LECs can inform preoperative diagnosis, which may enable conservative management.

Apropos of a case of pancreatic lymphoepithelial cyst: importance of the preoperative diagnosis by ecoendoscopy

The case was a 75-year-old female with dyspeptic symptoms of a 2 month duration. There was a polycystic lesion at the level of the uncinate pancreatic process of 44 x 42 x 34 mm on abdominal ultrasound and MRI, which caused a slight dilation of the main pancreatic duct. EUS was performed that identified a multicystic formation of 25x36 mm in the pancreatic body and FNA was performed of the lesion. The cytological analysis identified squamous epithelial cells with lymphoid tissue, which was compatible with a lymphoepithelial cyst, with no evidence of cell atypia or other signs of malignancy. Radiological control and monitoring of the lesion was performed and it has remained stable for 2 years.

A Rare Presentation of Pancreatic Lymphoepithelial Cyst: A Case Report and Review

Pancreatic lymphoepithelial cyst (LEC) is a rare, benign collection of keratinizing squamous epithelial cells encapsulated by lymphoid tissue. Because of its limited data and nonspecific features that can mimic malignant lesions, LECs can lead to unnecessary operations. A 62-year-old male with a known pancreatic mass presented with abdominal pain. CT scan showed an increased mass in the pancreatic head, and endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) revealed “rare fragments of benign-appearing squamous epithelium in a background of keratin debris, cyst contents, and scattered lymphocytes,” consistent with a lymphoepithelial cyst. Pancreatic LEC is an extremely rare lesion that comprises of only 0.5% of all pancreatic cysts. EUS-FNA has become the mainstay for diagnosing pancreatic LECs. Given the slow growing and benign nature, conservative management and observation is adequate for pancreatic LECs with excellent long-term outcome. With increasing number of imaging ordered by clinicians, it is anticipated that there will be a greater number of incidental pancreatic LECs detected. Thus, EUS-FNA should be utilized more frequently to help distinguish benign pancreatic LECs from premalignant or malignant lesions to avoid surgery.

Large lymphoepithelial cyst of pancreas: a rare entity managed using lumen-apposing metal stent-case report and review of the literature

Lymphoepithelial cysts (LECs) are extremely rare nonmalignant cysts of the pancreas. Asymptomatic LECs are managed conservatively, but symptomatic LECS have traditionally been managed with surgical resection. We report the first case of symptomatic infected LEC of the pancreas successfully managed with EUS guided endoscopic drainage with lumen-apposing metal stent. We also review the relevant literature and discuss the diagnosis and management of this rare cyst of the pancreas.

Lessons learned from 29 lymphoepithelial cysts of the pancreas: institutional experience and review of the literature

BACKGROUND

Lymphoepithelial cysts (LECs) are rare pancreatic cystic lesions. Since LECs are benign, preoperative diagnosis is important to differentiate from a cystic neoplasm and avoid unnecessary surgery. The aim of this study was to identify clinical, radiographic and cytopathologic features associated with LECs.

METHODS

A retrospective review was performed of patients diagnosed with LEC between 1995 and 2017 at our hospital. Clinicopathologic and radiographic imaging features were documented.

RESULTS

Of 29 patients with pancreatic LEC, 22 underwent surgical resection. The majority were male (n = 24) with a median age of 55 years (range, 21-74). During the evaluation, all patients underwent a CT, with endoscopic ultrasound (EUS) guided fine needle aspiration (FNA) biopsy (n = 22) and/or MRI/MRCP (n = 11) performed in a smaller number of patients. A combination of exophytic tumor growth on imaging and the presence of specific cytomorphologic features on the EUS-FNA cytology biopsy led to the correct diagnosis of LEC and prevention of unnecessary surgery in 7 patients.

DISCUSSION

Differentiating LECs from premalignant pancreatic cystic neoplasms remains difficult. Findings of an exophytic growth pattern of the lesion on abdominal imaging and the presence of specific cytomorphologic features in the EUS-FNA biopsy could help clinicians diagnose LEC preoperatively.

Pancreatic Lymphoepithelial Cysts Diagnosed with Endosonography-guided Fine Needle Aspiration

Although lymphoepithelial cysts (LECs) of the pancreas are benign lesions, most of them have been treated with surgical resection due to diagnostic difficulty. We report a 66-year-old woman diagnosed with pancreatic LECs. Abdominal ultrasound revealed two masses in the pancreas, which were not visible on the abdominal computed tomography. In an abdominal magnetic resonance imaging, pancreas lesions showed solid tumors, which revealed a low signal intensity on T1-, moderate high signal intensity on T2 weighted images, and homogeneous delayed enhancement in the portal venous phase. Endosonography (EUS) revealed two hypoechoic round masses measuring 1.5 cm and 4.5 cm in the body and tail of the pancreas, respectively. EUS-guided fine needle aspiration (FNA) revealed squamous cells, amorphous keratinous debris, and lymphocytes. The patient was diagnosed with LECs of the pancreas. For the duration of the follow-up period of two years, imaging studies were unchanged. EUS-FNA is useful in making a definite diagnosis and avoiding unnecessary surgery. This is the first case of pancreatic LECs diagnosed with EUS-FNA in Korea.

Endoscopic Ultrasound Imaging for Diagnosing and Treating Pancreatic Cysts

Cystic pancreatic lesions are increasingly diagnosed owing to the abundant use of cross-sectional imaging. Given their malignant potential, true pancreatic cysts should be considered for resection or periodic follow-up. Cystic lesions of the pancreas (CLPs) require further evaluation and management. Therefore, it is important to establish a solid diagnosis at the time of detection. Endoscopic ultrasound examination is the imaging modality of choice. Fine needle aspiration provides fluid for cytologic, biochemical, and molecular assays to classify lesions and predict biological behavior. This review provides an overview of the diagnosis and management of various types of commonly encountered true CLPs.