Imaging pitfalls of pancreatic serous cystic neoplasm and its potential mimickers

Cystic ductal adenocarcinoma of pancreas complicated with neuroendocrine tumor: A case report and review of literature

BACKGROUND

Difficulties in making an accurate preoperative diagnosis of cystic pancreatic lesions pose a challenge for radiologists. It would be helpful to report rare cases and review the literature.

CASE SUMMARY

In the present report, a case of a patient with a pancreatic cystic lesion initially misdiagnosed as a pseudocyst by radiologist was documented, which was later pathologically confirmed as pancreatic ductal adenocarcinoma with neuroendocrine tumor. However, subsequent literature review yielded no previous reports of pancreatic ductal adenocarcinoma with neuroendocrine tumors and cystic lesions. Therefore, literature on the imaging diagnosis of pancreatic cystic lesions was instead reviewed and discussed.

CONCLUSION

Careful evaluation of the characteristics revealed by multimodal imaging techniques, medical history, laboratory examination data and follow-up observations, is critical to the diagnosis and treatment of pancreatic cystic disease. We provide valuable insights into the diagnosis of pancreatic cystic disease through a rare case report and literature review.

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.

Microcystic serous cystadenoma of the pancreas causing biliary obstruction: a case report and review of the literature

Cystic tumors account for 15% of pancreatic tumors. Of these, serous microcystic adenomas represent 1-2% of pancreatic exocrine neoplasms. While typically benign, a small percentage possess malignant potential. Given imaging improvements, serous cystadenomas are being identified more frequently. A 63-year-old female was admitted with complaints of jaundice and unintentional weight loss. Abdominal computed tomography scan showed a 16 cm obstructive pancreatic mass near the porta hepatis region. Endoscopic ultrasonography and fine needle aspiration biopsy indicated a large pancreatic head cystic mass favoring serous microcystadenoma causing biliary and some pyloric obstruction. Malignant potential could not be ruled out because of size and symptoms. A pylorus-preserving pancreaticoduodenectomy revealed a cystic tumor invading the pancreatic duct and adhering to the duodenum of the pancreatic head. Pathology confirmed a 15 cm benign pancreatic serous cystadenoma. Although most serous cystadenomas are benign, surgical resection was prudent given the size, symptoms, and adjacent organ involvement.

Contrast-enhanced ultrasound (CEUS) and shear wave elastography (SWE) features for characterizing serous microcystic adenomas (SMAs): In comparison to pancreatic neuroendocrine tumors (pNETs)

Objectives

Serous microcystic adenoma (SMA), a primary benign pancreatic tumor which can be clinically followed-up instead of undergoing surgery, are sometimes mis-distinguished as pancreatic neuroendocrine tumor (pNET) in regular preoperative imaging examinations. This study aimed to analyze preoperative contrast-enhanced ultrasound (CEUS) and shear wave elastography (SWE) features of SMAs in comparison to pNETs.

Material and methods

In this retrospective study, patients with imaging-diagnosed pancreatic lesions were screened between October 2020 to October 2022 (ethical approval No. B2020-309R). Performing by a Siemens Sequoia (Siemens Medical Solutions, Mountain View, CA, USA) equipped with a 5C-1 curved array transducer (3.0-4.5 MHz), CEUS examination was conducted to observe the microvascular perfusion patterns of pancreatic lesions in arterial phase, venous/late phases (VLP) using SonoVue® (Bracco Imaging Spa, Milan, Italy) as the contrast agent. Virtual touch tissue imaging and quantification (VTIQ) - SWE was used to measure the shear wave velocity (SWV, m/s) value to represent the quantitative stiffness of pancreatic lesions. Multivariate logistic regression was performed to analyze potential ultrasound and clinical features in discriminating SMAs and pNETs.

Results

Finally, 30 SMA and 40 pNET patients were included. All pancreatic lesions were pathologically proven via biopsy or surgery. During the arterial phase of CEUS, most SMAs and pNETs showed iso- or hyperenhancement (29/30, 97 % and 31/40, 78 %), with a specific early honeycomb enhancement pattern appeared in 14/30 (47 %) SMA lesions. During the VLP, while most of the SMA lesions remained iso- or hyperenhancement (25/30, 83 %), nearly half of the pNET lesions revealed an attenuated hypoenhancement (17/40, 43 %). The proportion of hypoenhancement pattern during the VLP of CEUS differed significantly between SMAs and pNETs (P = 0.021). The measured SWV value of SMAs was significantly higher than pNETs (2.04 ± 0.70 m/s versus 1.42 ± 0.44 m/s, P = 0.002). Taking a SWV value > 1.83 m/s as a cutoff in differentiating SMAs and pNETs, the area under the receiver operating characteristic curve (AUROC) was 0.825, with sensitivity, specificity and likelihood ratio (+) of 85.71 %, 72.73 % and 3.143, respectively. Multivariate logistic regression revealed that SWV value (m/s) of the pancreatic lesion was an independent variable in discriminating SMA and pNET.

Conclusion

By comprehensively evaluating CEUS patterns and SWE features, SMA and pNET may be well differentiated before the operation. While SMA typically presents as harder lesion in VTIQ-SWE, exhibiting a specific honeycomb hyperenhancement pattern during the arterial phase of CEUS, pNET is characterized by relative softness, occasionally displaying a wash-out pattern during the VLP of CEUS.

Increased Uptake in Microcystic Serous Cystadenoma Mimicking Pancreatic Neuroendocrine Tumor on 68 Ga-DOTATATE PET/MRI

ABSTRACT

A 2.6-cm solid cystic lesion in the pancreatic head was found in a 51-year-old woman on CT. A pancreatic neuroendocrine tumor was suspected, and a 68 Ga-DOTATATE PET/MRI was performed, which showed increased tracer uptake in the lesion. However, postsurgical pathologic examination indicated a pancreatic serous cystadenoma. Here, we reported a case of microcystic pancreatic serous cystadenoma that could be misdiagnosed as a pancreatic neuroendocrine tumor on a 68 Ga-DOTATATE PET/MRI.

Diagnostic, Structured Classification and Therapeutic Approach in Cystic Pancreatic Lesions: Systematic Findings with Regard to the European Guidelines

Due to the increasing use of cross-sectional imaging techniques and new technical possibilities, the number of incidentally detected cystic lesions of the pancreas is rapidly increasing in everyday radiological routines. Precise and rapid classification, including targeted therapeutic considerations, is of essential importance. The new European guideline should also support this. This review article provides information on the spectrum of cystic pancreatic lesions, their appearance, and a comparison of morphologic and histologic characteristics. This is done in the context of current literature and clinical value. The recommendations of the European guidelines include statements on conservative management as well as relative and absolute indications for surgery in cystic lesions of the pancreas. The guidelines suggest surgical resection for mucinous cystic neoplasm (MCN) ≥ 40 mm; furthermore, for symptomatic MCN or imaging signs of malignancy, this is recommended independent of its size (grade IB recommendation). For main duct IPMNs (intraductal papillary mucinous neoplasms), surgical therapy is always recommended; for branch duct IPMNs, a number of different risk criteria are applicable to evaluate absolute or relative indications for surgery. Based on imaging characteristics of the most common cystic pancreatic lesions, a precise diagnostic classification of the tumor, as well as guidance for further treatment, is possible through radiology.

Preliminary evaluation of 18F-FDG-PET/MRI for differentiation of serous from nonserous pancreatic cystic neoplasms: a pilot study

OBJECTIVES

The aim of the study was to evaluate preliminary feasibility of 18F-FDG-PET/MRI in differentiation of pancreatic serous cystic neoplasms (SCNs) from non-SCNs.

METHODS

From August 2017 to June 2019, 10 patients (3 men, 7 women; mean age, 63 years) previously diagnosed with pancreatic cystic neoplasm underwent simultaneous 18F-FDG-PET/MRI prospectively on an integrated 3-Tesla hybrid PET/MRI scanner. PET images were analyzed visually and semiquantitatively measuring standardized uptake values (SUV) including lesion SUVmax and SUVmean, lesion to pancreas and lesion to liver SUVmax and SUVmean ratio independent of MRI diagnosis. The reference standard for lesion diagnosis was by MRI features and interval follow-up.

RESULTS

Visual assessment of PET images demonstrated uptake in 57% of SCNs. Lesion to liver SUVmax ratio of ≥0.5 showed the highest accuracy (90%) and area under the curve (0.9) followed by lesion SUVmax of ≥1.6 and lesion to pancreas SUVmax ratio of ≥0.77 for diagnosis of SCN. The sensitivity for lesion SUVmax of ≥1.6 was less than two other ones (71 versus 100%). All non-SCNs exhibited SUVmax value less than 1.6 while 33 and 66% demonstrated lesion to liver SUVmax ratio of >0.5 and lesion to pancreas SUVmax ratio of >0.77, respectively. PET/MRI specificity was 67, 100, 67 and 33% through lesion to liver SUVmax ratio, lesion SUVmax, lesion SUVmean and lesion to pancreas SUVmax ratio, respectively, for diagnosis of SCN.

CONCLUSION

Preliminary results show that PET/MRI utilization is promising for differentiation of pancreatic SCN from non-SCN lesions. This could reduce need for surveillance imaging or avoidance of unnecessary intervention in pancreatic cystic neoplasms with uncertain diagnoses.

Nonmucinous Cystic Lesions of the Pancreas

CONTEXT.—

Pancreatic cystic lesions are increasingly diagnosed. Among other criteria, they are often distinguished in mucinous versus nonmucinous cysts. Mucinous pancreatic cystic lesions have received increasing attention, especially those known as precursors of pancreatic ductal adenocarcinoma. However, the group of nonmucinous cystic lesions of the pancreas includes numerous entities that may pose a diagnostic challenge. Their accurate diagnosis and classification are crucial for adequate patient management.

OBJECTIVE.—

To review the spectrum of nonmucinous cystic lesions of the pancreas, taking into consideration their epidemiology and typical clinical context, their characteristic gross morphology and histomorphology, as well as their immunohistochemical and molecular profile.

DATA SOURCES.—

Literature was searched and reviewed with MEDLINE via PubMed. Macroscopic and microscopic images were obtained from the archives of the Institute of Pathology, Heinrich Heine University and University Hospital of Duesseldorf, Germany.

CONCLUSIONS.—

Nonmucinous cysts of the pancreas comprise numerous, mostly rare entities displaying different biological behaviors. The most frequent are serous cystic neoplasms, solid-pseudopapillary neoplasms, cystic neuroendocrine tumors, and pancreatitis-associated pseudocysts. Accurate diagnosis can be achieved if characteristic clinical context, histomorphology, and immunoprofile are taken into account.

An Atypical Presentation of Pancreatic Pseudocyst Masquerading as Solid Pseudopapillary Neoplasm of Pancreas

Pancreatic pseudocysts are the most common cystic lesions of the pancreas, and often present as a consequence of acute or chronic pancreatitis. On the other hand, cystic neoplasms of the pancreas are rare, but pose a significant diagnostic challenge. The differentiation between these entities often relies on the clinical features and characteristic radiological evidence. However, the diagnostic dilemma persists, leading to misdiagnosis and inappropriate treatment. We present a case of pancreatic pseudocyst in a 49-year-old male, which clinically and radiologically mimicked solid pseudopapillary neoplasm, a rare type of cystic neoplasm of the pancreas.

Giant symptomatic serous cystadenoma mimicking carcinoma: A case report and literature review

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The diagnosis of serous cystadenoma is challenging.

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Surgery may be indicated for select serous cystadenoma.

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Serous cystadenocarcinoma is a rare entity and histologically indistinguishable from its benign counterpart.

Introduction

Advanced imaging has led to an increase in the incidental diagnosis of pancreatic cysts. Serous cystadenomas (SCAs) account for nearly 30% of cases. These are typically considered benign lesions but up to 16% of cases are resected for aggressive behavior and symptoms.

Presentation of case

A 64 year old female presented with a large incidental cyst in the pancreatic body. Pre-operative imaging conferred a diagnosis of SCA. After 2 years the cyst grew resulting in abdominal pain. Enlargement was associated with splenic vein occlusion and varices of the short gastric vessels. This change in behavior was concerning for malignant transformation. The cyst was resected by distal pancreatectomy and splenectomy. The patient recovered with minimal morbidity. Final pathology revealed a 15.5 × 10.3 × 8.5 cm SCA with negative margins.

Discussion

In this case a patient presents with aggressive radiographic features and new symptoms suggesting malignant transformation of a previously diagnosed SCA on imaging. Although malignant variants can be diagnosed by findings of metastatic deposits at the time of surgery or as recurrence years later, histologic findings cannot discriminate benign from malignant potential. Preoperative imaging is challenging with erroneous characterization in nearly 60% of cases.

Conclusion

Based on the low risk of malignancy, selective surgical resection for SCA appears warranted. Accepted indications for surgery include development of symptoms or concern for correct diagnosis in a medically fit individual. Routine resection for cysts >4 cm has been suggested however, prospective studies are needed to determine benefit over risk rationale.

Radiological Workup of Cystic Neoplasms of the Pancreas

Pancreatic cystic lesions are being detected with increasing frequency because of increased use and improved quality of cross-sectional imaging techniques. Pancreatic cystic lesions encompass non-neoplastic lesions (such as pancreatitis-related collections) and neoplastic tumors. Common cystic pancreatic neoplasms include serous cystadenomas, mucinous cystic neoplasms, intraductal papillary mucinous neoplasms, and solid pseudopapillary tumors. These cystic pancreatic neoplasms may have typical morphology, but at times show overlapping imaging features on cross-sectional examinations. This article reviews the classical and atypical imaging features of commonly encountered cystic pancreatic neoplasms and presents the limitations of current cross-sectional imaging techniques in accurately classifying pancreatic cystic lesions.

Middle segment pancreatectomy for a solid serous cystadenoma diagnosed by MRCP and review of the literature: A case report

Solid serous cystadenoma of the pancreas is the rarest subtype of serous cystadenoma. Cystic structures are difficult to recognize by imaging studies. In the clinical setting, it is crucial to discriminate a solid serious cystadenoma from other solid pancreatic tumors. The present study reported a case of solid serous cystadenoma in which the magnetic resonance cholangiopancreatography (MRCP) findings were useful for diagnosis and decision-making regarding the surgical strategy, with a review of the previous reports of solid serous cystadenoma. A 50-year-old woman was referred to our hospital for investigation of a pancreatic body mass. A 2-cm hypervascular solid tumor was revealed by computed tomography. No typical radiological imaging findings of small cysts were detected, such as a honeycomb structure, and an adequate specimen could not be gained by biopsy under endoscopic ultrasonography. However, the tumor showed high intensity on MRCP, suggesting its cystic nature. A solid serous cystadenoma was suspected based on these radiological findings, and middle segment pancreatectomy was performed as a function-preserving surgery. The histological findings were compatible with a solid serous cystadenoma. In conclusion, MRCP imaging may be helpful for diagnosis and decision-making regarding the most appropriate surgical method for solid serous cystadenomas.

Mucinous nonneoplastic cyst of the pancreas: CT and MRI appearances

PURPOSE

The purpose of this retrospective study was to evaluate imaging features of mucinous nonneoplastic cyst (MNNC) of the pancreas.

MATERIALS AND METHODS

Three (0.9%) patients with MNNC of the pancreas were found in 335 surgically resected pancreatic cystic lesions. Three MDCT and two MRI/MRCP studies were retrospectively reviewed.

RESULTS

Three cases of MNNC were found in the pancreatic neck, body, and tail, respectively. All the three cases were multilocular without communication with the main pancreatic duct (MPD), although upstream MPD dilatation was seen in two of the three cases. The signal intensity of the cyst fluid was low on T1-weighted, high on T2-weighted, and low on diffusion-weighted images. Cyst wall was thin in two cases, and the remaining case with obstructive pancreatitis showed visible cyst wall enhancement.

CONCLUSION

Imaging findings of MNNC of the pancreas were nonspecific without communication with the MPD. Cyst wall is typically thin without visible enhancement.

Serous pancreatic neoplasia, data and review

AIM

To describe the imaging features of serous neoplasms of the pancreas using ultrasound, endoscopic ultrasound, computed tomography and magnetic resonance imaging.

METHODS

This multicenter international collaboration enhances a literature review to date, reporting features of 287 histologically confirmed cases of serous pancreatic cystic neoplasms (SPNs).

RESULTS

Female predominance is seen with most SPNs presenting asymptomatically in the 5^th through 7^th decade. Mean lesion size was 38.7 mm, 98% were single, 44.2% cystic, 46% mixed cystic and solid, and 94% hypoechoic on B-mode ultrasound. Vascular patterns and contrast-enhancement profiles are described as hypervascular and hyperenhancing.

CONCLUSION

The described ultrasound features can aid differentiation of SPN from other neoplastic lesions under most circumstances.

Pancreatic serous cystic neoplasms accompanying other pancreatic tumors

Serous cystic neoplasms (SCNs) are benign cystic neoplasms that predominantly occur in the tail of the pancreas in elderly women. It is well known that patients with von Hippel-Lindau syndrome can develop SCNs and neuroendocrine tumors in the pancreas. However, our understanding on SCNs accompanying other pancreatic tumors (SCNAOPTs) is limited. We compared the clinicopathological features of 15 surgically resected SCNAOPTs with 259 conventional SCNs. The prevalence of SCNAOPT was 5%. The SCNAOPTs were significantly smaller than conventional solitary SCNs, and they were more commonly observed in the head of the pancreas, whereas conventional solitary SCNs were more frequently noted in the body and tail. However, no differences were found in terms of sex, patient age, or the gross patterns of the SCNs. Accompanying neoplasms included 7 intraductal papillary mucinous neoplasms, 1 colloid carcinoma arising from intraductal papillary mucinous neoplasm, 6 neuroendocrine tumors, and 1 solid pseudopapillary neoplasm. Four neuroendocrine tumors associated with von Hippel-Lindau syndrome occurred as multiples, whereas 2 neuroendocrine tumors without von Hippel-Lindau syndrome were solitary. In summary, SCNAOPTs comprise 5% of all SCNs and tend to be smaller and located in the head of the pancreas. Common accompanying tumors include intraductal papillary mucinous neoplasms, neuroendocrine tumors, and other neoplasms such as colloid carcinoma and solid pseudopapillary neoplasm.

A distinctive myoepithelial hamartoma of the pancreas histologically confirmed in the mother of a previously reported patient

We encountered a 62-year-old female patient with a distinctive pancreatic myoepithelial hamartoma characterized by dilated loops formed by pancreatic branch ducts. The patient, who experienced recurrent acute pancreatitis caused by pancreatic juice stasis, underwent subtotal stomach-preserving pancreatoduodenectomy, achieving remission of pancreatitis. Computed tomography (CT) and magnetic resonance cholangiopancreatography (MRCP) demonstrated a honeycomb appearance of the pancreatic head, consisting largely of loop-forming dilated pancreatic branch ducts. Radiography of resected specimens demonstrated a tortuous main pancreatic duct that narrowed in the head, but communicated with the pancreatic branch ducts forming intricate loops within the lesion. Histologic examination showed dilated pancreatic ducts embedded in thick layers of smooth muscle, leading to a diagnosis of myoepithelial hamartoma. Her son shared a similar clinical course, radiologic findings, and histopathologic findings with his mother. MRCP demonstrated a honeycomb appearance of the pancreatic head in her daughter, who complained of persistent diarrhea. To our knowledge, this is the first English-language reports of such a myoepithelial hamartoma of the pancreas showing familial occurrence.