Lymphoepithelial cyst of pancreas: spectrum of radiological findings with pathologic correlation

Lymphoepithelial cyst of the pancreas: can common imaging features help to avoid resection?

BACKGROUND

Differentiation of cystic pancreatic neoplasms remains a challenging task for radiologists regarding the main aim of identifying malignant and premalignant lesions.

PURPOSE

The study aimed to compare the radiological features of lymphoepithelial cysts (LEC) with other cystic pancreatic lesions, which could help to differentiate them in order to avoid unnecessary resection.

MATERIAL AND METHODS

We retrospectively reviewed 10 cases of resected and histopathologically confirmed LECs during a 12-year period with available imaging studies; 20 patients with mucinous cystic neoplasms (MCN), 20 patients with branch-duct intraductal papillary mucinous neoplasms (BD-IPMN), and 20 patients with serous cystic neoplasms (SCN) were selected to serve as control groups. Imaging findings as well as clinical data were analyzed.

RESULTS

The following imaging morphology of LEC was identified: simple cystic appearance (20%) and mixed cystic-solid appearance (80%) with either a diffuse subsolid component (30%) or mural nodule(s) (50%). All lesions revealed exophytic location with a strong male predominance (9:1). MCNs occurred exclusively in middle-aged women, IPMN in both sexes showed slight male predominance (13:7), and SCN showed female predominance (5:15). Median patient age in LEC (48.5, IQR 47-54.5) was significantly younger compared to IPMN (p < 0.001) and SCN (p = 0.02). Unenhanced CT attenuation of LEC was higher than MCNs (p = 0.025) and IPMNs (p = 0.021), showing no significant difference to SCN (p = 0.343).

CONCLUSION

The present study provides key radiological features of LEC for the differentiation from other cystic pancreatic lesions such as increased CT attenuation in the unenhanced phase, absence of a connection to the main pancreatic duct (MPD), and exophytic location. In addition to these imaging features, clinical data, such as male predominance in LEC, must be considered for the differentiation of cystic pancreatic lesions.

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.

MRI of mucinous pancreatic cystic lesions: a new updated morphological approach for the differential diagnosis

Pancreatic cystic lesions (PCLs) have been increasingly identified over the past 2 decades due to the widespread use of high-resolution non-invasive abdominal imaging. They cover a vast spectrum, from benign to malignant and invasive lesions, thus they constitute a significant clinical entity. Among PCLs, mucin-producing lesions are those at risk of progression to malignancy. They include mucinous cystic neoplasms (MCN) and intraductal papillary mucinous neoplasms (IPMN). The diagnosis and management of these cystic lesions are a dilemma since there is a significant overlap in the morphology of benign and premalignant lesions. At the moment, there is no single test that will allow a correct diagnosis in all cases. Magnetic resonance (MR) and endoscopic ultrasound (EUS) morphology, with cyst fluid analysis and cytohistology done with EUS-guided procedure are the best techniques that can narrow the differential diagnosis and identify potentially malignant lesions requiring resection from those requiring follow-up only. The purpose of this paper is to present an updated review of MR imaging findings of mucinous PCLs and to provide a new morphological approach that can serve as a practical guide for the diagnosis of these lesions, allowing a more confident characterization and avoiding relevant misdiagnosis. Furthermore, we provide some information about EUS and cystic fluid analysis and cytohistology, since they are diagnostic modalities that radiologists and surgeons should be familiar with.

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.

Elevating pancreatic cystic lesion stratification: Current and future pancreatic cancer biomarker(s)

Pancreatic ductal adenocarcinoma (PDAC) is an incredibly deadly disease with a 5-year survival rate of 9%. The presence of pancreatic cystic lesions (PCLs) confers an increased likelihood of future pancreatic cancer in patients placing them in a high-risk category. Discerning concurrent malignancy and risk of future PCL progression to cancer must be carefully and accurately determined to improve survival outcomes and avoid unnecessary morbidity of pancreatic resection. Unfortunately, current image-based guidelines are inadequate to distinguish benign from malignant lesions. There continues to be a need for accurate molecular and imaging biomarker(s) capable of identifying malignant PCLs and predicting the malignant potential of PCLs to enable risk stratification and effective intervention management. This review provides an update on the current status of biomarkers from pancreatic cystic fluid, pancreatic juice, and seromic molecular analyses and discusses the potential of radiomics for differentiating PCLs harboring cancer from those that do not.

Pancreatic Cytology

The diagnostic approach to pancreaticobiliary disease requires a multidisciplinary team in which the cytopathologist plays a crucial role. Fine-needle aspiration, obtained by endoscopic ultrasound, is the diagnostic test of choice for pancreatic lesions. Preoperative clinical management depends on many factors, many of which rely on accurate cytologic assessment. Pancreaticobiliary cytology is wrought with diagnostic pitfalls. Clinical history, imaging studies, cytology samples, and ancillary tests, including immunohistochemistry, biochemical analysis, and genetic sequencing, are integral to forming a complete diagnosis and guiding optimal patient management. This article reviews clinical aspects and the diagnostic work-up of commonly encountered diagnostic entities within the field of pancreatic cytology.

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.

Paraduodenal pancreatitis: benign and malignant mimics at MRI

Paraduodenal pancreatitis, also known as groove pancreatitis, is a rare form of chronic pancreatitis that masquerades as pancreatic adenocarcinoma affecting the pancreaticoduodenal groove, a potential space between the head of the pancreas, duodenum, and common bile duct. Two forms of groove pancreatitis have been described. The segmental form involves the pancreatic head with development of scar tissue within the groove, whereas the pure form affects the groove only, sparing the pancreatic head. Imaging findings of groove pancreatitis often overlap with primary duodenal, ampullary, or pancreatic neoplasms, which often results in a diagnostic challenge. In addition, paraduodenal pancreatitis can be mistaken for cystic pancreatic lesions, especially when there is involvement of the duodenal wall. Preoperative recognition of this entity is very important in order to avoid unnecessary procedures, although surgery, such as pancreaticoduodenectomy, may still be required to relieve obstructive symptoms. In this article, the pathophysiology and magnetic resonance imaging characteristics of paraduodenal pancreatitis and important benign and malignant mimics are discussed.

Lymphoepithelial Cysts of the Pancreas: CT and MRI Features

Objective: Describe CT and MRI features of the lymphoepithelial cyst (LEC) of the pancreas. Methods: The authors identified 13 cases of LEC by searching their institutional electronic medical archives from 2004 to 2020. All of the patients had CT scans and six patients had both a CT and MRI. The final diagnosis was established either by fine-needle aspiration with cytopathology (n=6) or surgical resection (n=7). Results: The mean diameter of the cysts was 36 mm (range: 6–93 mm). Almost all of the cysts were exophytic (92%) and solitary (85%), favouring the tail (54%) or body (38%) of the pancreas. LECs were either oval (62%) or round (39%) and had well-defined contours. All LECs showed T2 hyperintensity and T1 hypointensity; however, the signal was heterogeneous. Diffusion-weighted imaging showed restricted diffusion in all cases. On CT, LECs commonly showed complex fluid density (>15 HU) with no visible septation, enhancement or calcification. Conclusion: LECs have a distinguishing feature on MRI, which is restricted diffusion on diffusion-weighted imaging. This is presumably secondary to the presence of keratin, which can be a helpful feature differentiating LECs from other pancreatic cystic neoplasms. Besides this, LECs predominantly appear as solitary and exophytic lesions, with complex fluid density on CT and heterogeneous hypointense T1 and heterogenous hyperintense T2 signal on MRI.