Rare nonneoplastic cysts of pancreas

Mucinous non neoplastic cyst of the pancreas: a case report

The aim of this study was to introduce a patient with mucinous nonneoplastic cyst (MNNC) at an unusual age. MNNCs of the pancreas are uncommon primary tumors, which affect middle-aged women in their fifth decade of life and have significant malignant potential. Therefore, it is important to accurately diagnose and remove them. This case is a 28-year-old woman patient who presented with a pain in the right and upper abdomen from 3 months ago and worsened at night. A cystic lesion was observed near the upper bridge of the left kidney in abdominal ultrasonography. Contrast-enhanced abdominal computed tomography (CT) scan showed a cystic lesion in the trunk and umbilical cord of the pancreas. The patient underwent surgery and the mass was removed and the MNNC was diagnosed.

Gastrointestinal Intramural Pancreatic Pseudocysts in a Dog: A Case Report and Human Literature Review

A 9.5 yr old Yorkshire terrier presented with chronic intermittent vomiting and lethargy of 1.5 yr duration that progressed to generalized weakness. Insulin:glucose ratio was consistent with an insulinoma. Triple-phase computed tomography revealed a mid-body pancreatic nodule. The mid-body pancreatic nodule was enucleated; histopathology was consistent with an insulinoma. Two weeks after the operation, the dog presented for anorexia and diarrhea. Abdominal ultrasound revealed a thick-walled cystic lesion along the dorsal stomach wall. An intramural gastric pseudocyst was diagnosed via exploratory laparotomy and intraoperative gastroscopy. Comparison of amylase and lipase levels of the cystic fluid with that of concurrent blood serum samples confirmed the lesion was of pancreatic pseudocyst origin. The gastric pseudocyst was omentalized. Two weeks after the operation, the dog re-presented for anorexia, regurgitation, and diarrhea. An intramural duodenal pseudocyst was identified and treated with a duodenal resection and anastomosis. The dog has remained asymptomatic and recurrence free based on serial abdominal ultrasounds 22 mo following insulinoma removal. To our knowledge, this phenomenon of pancreatic pseudocysts forming in organs other than the pancreas has not been reported in dogs. This case report and comprehensive human literature review purpose is to raise awareness of this disease process in dogs.

Cystic pancreatic lesions: MR imaging findings and management

Cystic pancreatic lesions (CPLs) are frequently casual findings in radiological examinations performed for other reasons in patients with unrelated symptoms. As they require different management according to their histological nature, differential diagnosis is essential. Radiologist plays a key role in the diagnosis and management of these lesions as imaging is able to correctly characterize most of them and thus address to a correct management. The first step for a correct characterization is to look for a communication between the CPLs and the main pancreatic duct, and then, it is essential to evaluate the morphology of the lesions. Age, sex and a history of previous pancreatic pathologies are important information to be used in the differential diagnosis. As some CPLs with different pathologic backgrounds can show the same morphological findings, differential diagnosis can be difficult, and thus, the final diagnosis can require other techniques, such as endoscopic ultrasound, endoscopic ultrasound-fine needle aspiration and endoscopic ultrasound-through the needle biopsy, and multidisciplinary management is important for a correct management.

Large-duct pattern invasive adenocarcinoma of the pancreas–a variant mimicking pancreatic cystic neoplasms: A minireview

Pancreatic cancer currently has no subtypes that inform clinical decisions; hence, there exists an opportunity to rearrange the morphological and molecular taxonomy that guides a better understanding of tumor characteristics. Nonetheless, accumulating studies to date have revealed the large-duct type variant, a unique subtype of pancreatic ductal adenocarcinoma (PDA) with cystic features. This subtype often radiographically mimics intraductal papillary mucinous neoplasms (IPMNs) and involves multiple small cysts occasionally associated with solid masses. The “bunch-of-grapes” sign, an imaging characteristic of IPMNs, is absent in large-duct PDA. Large-duct PDA defines the mucin profile, and genetic alterations are useful in distinguishing large-duct PDA from IPMNs. Histologically, neoplastic ducts measure over 0.5 mm, forming large ductal elements. Similar to classic PDAs, this subtype is frequently accompanied by perineural invasion and abundant desmoplastic reactions, and KRAS mutations in codon 12 are nearly ubiquitous. Despite such morphological similarities with IPMNs, the prognosis of large-duct PDA is equivalent to that of classic PDA. Differential diagnosis is therefore essential.

The faith of non-surveilled pancreatic cysts: a bicentric retrospective study

BACKGROUND

Incidental discovery of pancreatic cystic neoplasms (PCLs) is a common and steadily increasing occurrence. The aim of this study was to investigate a cohort of patients presenting with incidentally detected PCLs which were not included in a surveillance protocol, and to compare their risk of malignant evolution with that of systematically surveilled lesions.

MATERIALS AND METHODS

A population of PCLs which did not receive surveillance over a period >10 years (population A) was selected at the Medical University of Vienna. A group of "low risk" branch duct intraductal papillary mucinous neoplasm ≤15 mm in size upon diagnosis undergoing a regular follow-up of at least 5 years at the University of Verona was selected as control (population B). The incidence of pancreatic cancer (PC), cumulative risk of PC and disease-specific survival were compared.

RESULTS

Overall, 376 patients with non-surveilled PCLs were included in study group A and compared to 299 patients in group B. This comparison resulted in similar incidence rates of PC (1.6% vs 1.7%, p = 0.938), a strong similarity in terms of disease-specific mortality rates (1.3% vs 0.3%, p = 0.171) and the 5- and 10-year cumulative risk of PC (≅ 1% and 2%, p = 0.589) and DSS (≅ 100% and 98%, p = 0.050).

CONCLUSION

The "price to pay" for a negligence-based policy in the population of non-surveilled PCLs was reasonable, and the incidence of PC was comparable to that reported for a population of low-risk cysts enrolled to a standardized surveillance protocol.

Diagnosis and differentiation of mature cystic teratoma of pancreas from its mimics: A case report

INTRODUCTION

Mature cystic teratoma originating in the pancreas is very unusual, often observed as an incidental finding during routine examinations or recognized perioperatively as the patients present with very unspecific clinical symptoms. The confirmatory diagnosis of a pancreatic cystic teratoma is generally made by histopathology after surgical excision. So, the preoperative diagnosis is very challenging, especially differentiation from the other pancreatic pathologies.

PATIENT CONCERNS

A 23-year-old woman was admitted to our hospital with a complaint of mild grade periumbilical abdominal pain. A pancreatic mass was revealed on a preliminary abdominal ultrasound examination. Her medical history was unremarkable with no long-standing illness or malignancy.

DIAGNOSIS

Mature cystic teratoma in the head of the pancreas.

INTERVENTIONS

Roux-enY choledochojejunostomy with gastrojejunostomy was performed, excising the tumor from the pancreatic head.

OUTCOMES

The postoperative course was uneventful; the patient was asymptomatic and has no evidence of recurrence on a 2-year follow up.

CONCLUSIONS

Pancreatic cystic teratoma is a benign, well-differentiated, and extremely rare congenital tumor. MRI is the choice of imaging modality and phase-GRE or fat suppression is the best technique for pre-operative diagnosis.

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.

Association between macroscopically visible tissue samples and diagnostic accuracy of EUS-guided through-the-needle microforceps biopsy sampling of pancreatic cystic lesions

BACKGROUND AND AIMS

EUS-guided through-the-needle biopsy (TTNB) sampling has been reported to improve diagnostic yield compared with cytology for the evaluation of pancreatic cystic lesions (PCLs). The number of macroscopically visible tissue samples needed to reach an adequate diagnosis is still unknown.

METHODS

This is a retrospective, single-center study on consecutive patients with PCLs with risk features (cyst >3 cm, thickened wall, cyst growth during follow-up, and mural nodules) who underwent TTNB sampling. The capability of differentiating mucinous versus nonmucinous cysts, ability to obtain a cyst-lining epithelium, definition of the grade of dysplasia, and specific diagnosis of cyst histotype were evaluated for 1, 2, or 3 TTNB macroscopically visible specimens.

RESULTS

Sixty-one patients were evaluated. A 100% histologic adequacy was reached by 2 samples (P = .05 versus 1). Compared with cytology, 1 TTNB specimen improved the possibility of defining cyst histotype (P < .0001), whereas 2 specimens increased all 4 diagnostic categories (P < .003). Two specimens also increased diagnostic yield compared with 1 sample (P < .085). The collection of a third sample did not improve the value of any diagnostic categories. A specific diagnosis was reached in 74% of patients with 2 histologic samples. The diagnostic reliability of TTNB sampling compared with surgical histology was 90%, with a 22.9% rate of adverse events.

CONCLUSIONS

Two TTNB macroscopically visible specimens reached 100% histologic adequacy and a specific diagnosis in 74% of patients. The collection of a third specimen did not add any additional information and should be avoided to possibly decrease the risk of adverse events.

Superparamagnetic iron-oxide-enhanced diffusion-weighted magnetic resonance imaging for the diagnosis of intrapancreatic accessory spleen

PURPOSE

To evaluate the diagnostic performance of superparamagnetic iron-oxide (SPIO)-enhanced diffusion-weighted image (DWI) for distinguishing an intrapancreatic accessory spleen from pancreatic tumors.

MATERIALS AND METHODS

Twenty-six cases of intrapancreatic accessory spleen and nine cases of pancreatic tail tumors [neuroendocrine tumor (n = 8) and pancreatic adenocarcinoma (n = 1)] were analyzed. Two blind reviewers retrospectively reviewed the SPIO-enhanced magnetic resonance imaging (MRI) scans. The lesion visibility grades were compared and the diagnostic performance of SPIO-enhanced DWI was compared to those of SPIO-enhanced T2WI and T2*WI with the use of a receiver operating characteristic (ROC) analysis.

RESULTS

The grade of lesion visibility was the highest on DWI [mean ± standard deviation (SD): 2.8 ± 0.3] followed by T2WI (2.3 ± 0.7, p < 0.001) and T2*WI (2.1 ± 0.7, p < 0.0001). Reviewers 1 and 2 correctly characterized the presence or absence of SPIO uptake in 34 of 35 cases (97.1%) on DWI, 24 (68.6%) and 25 (71.4%) cases on T2WI, respectively, and 16 (45.7%) and 17 (48.6%) cases on T2*WI. The area under the ROC curve (AUC) of DWI was 0.974 and 0.989 for reviewers 1 and 2, respectively. For Reviewer 1, the AUC of DWI was significantly higher than that of T2*WI (0.756, p < 0.01), although it was not significantly different from that of T2WI (0.868, p = 0.0857). For Reviewer 2, the AUC of DWI was significantly higher than those of T2WI (0.846, p < 0.05) and T2*WI (0.803, p < 0.01).

CONCLUSION

The diagnostic performance of SPIO-enhanced DWI was better than those of SPIO-enhanced T2*WI and T2WI for the diagnosis of intrapancreatic accessory spleen.

Diagnostic ability of artificial intelligence using deep learning analysis of cyst fluid in differentiating malignant from benign pancreatic cystic lesions

The diagnosis of pancreatic cystic lesions remains challenging. This study aimed to investigate the diagnostic ability of carcinoembryonic antigen (CEA), cytology, and artificial intelligence (AI) by deep learning using cyst fluid in differentiating malignant from benign cystic lesions. We retrospectively reviewed 85 patients who underwent pancreatic cyst fluid analysis of surgical specimens or endoscopic ultrasound-guided fine-needle aspiration specimens. AI using deep learning was used to construct a diagnostic algorithm. CEA, carbohydrate antigen 19-9, carbohydrate antigen 125, amylase in the cyst fluid, sex, cyst location, connection of the pancreatic duct and cyst, type of cyst, and cytology were keyed into the AI algorithm, and the malignant predictive value of the output was calculated. Area under receiver-operating characteristics curves for the diagnostic ability of malignant cystic lesions were 0.719 (CEA), 0.739 (cytology), and 0.966 (AI). In the diagnostic ability of malignant cystic lesions, sensitivity, specificity, and accuracy of AI were 95.7%, 91.9%, and 92.9%, respectively. AI sensitivity was higher than that of CEA (60.9%, p = 0.021) and cytology (47.8%, p = 0.001). AI accuracy was also higher than CEA (71.8%, p < 0.001) and cytology (85.9%, p = 0.210). AI may improve the diagnostic ability in differentiating malignant from benign pancreatic cystic lesions.

European evidence-based guidelines on pancreatic cystic neoplasms

Evidence-based guidelines on the management of pancreatic cystic neoplasms (PCN) are lacking. This guideline is a joint initiative of the European Study Group on Cystic Tumours of the Pancreas, United European Gastroenterology, European Pancreatic Club, European-African Hepato-Pancreato-Biliary Association, European Digestive Surgery, and the European Society of Gastrointestinal Endoscopy. It replaces the 2013 European consensus statement guidelines on PCN. European and non-European experts performed systematic reviews and used GRADE methodology to answer relevant clinical questions on nine topics (biomarkers, radiology, endoscopy, intraductal papillary mucinous neoplasm (IPMN), mucinous cystic neoplasm (MCN), serous cystic neoplasm, rare cysts, (neo)adjuvant treatment, and pathology). Recommendations include conservative management, relative and absolute indications for surgery. A conservative approach is recommended for asymptomatic MCN and IPMN measuring <40 mm without an enhancing nodule. Relative indications for surgery in IPMN include a main pancreatic duct (MPD) diameter between 5 and 9.9 mm or a cyst diameter ≥40 mm. Absolute indications for surgery in IPMN, due to the high-risk of malignant transformation, include jaundice, an enhancing mural nodule >5 mm, and MPD diameter >10 mm. Lifelong follow-up of IPMN is recommended in patients who are fit for surgery. The European evidence-based guidelines on PCN aim to improve the diagnosis and management of PCN.

An Intrapancreatic Accessory Spleen That Was Difficult to Diagnose Due to Temporal Changes after Splenectomy

Accessory spleen (AS) is common anomaly, and 20% of AS cases occur in the pancreatic tail. An intrapancreatic AS can be difficult to distinguish from pancreatic neoplasms. In most cases, an AS is described as a hypervascular and solitary tumor, but an AS sometimes takes other forms. We herein report a rare case of an intrapancreatic AS with temporal changes in its appearance after splenectomy, which mimicked aspects of pancreatic cancer. Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) and ^99mTc sulfur colloid scintigraphy were useful for the diagnosis.

[Simple mucinous cyst of the pancreas: Case-report and literature review]

Simple mucinous cyst of the pancreas is an unusual pancreatic cyst, first described by Kosmahl et al. in 2002 with 5 cases. We describe a case of simple mucinous cyst of the pancreas, followed by a literature review. The physiopathology of this cyst is still unclear. It is an epithelial cyst, presenting as unilocular cystic lesion of the pancreatic body or tail, with a clear content, and no communication with the pancreatic duct. Microscopically, the cyst is lined by mucin-producing cells with mild atypia, and contains a fibrous wall without ovarian-like stroma. The prognosis is excellent, as no recurrent disease and progression to malignancy have been described. The non neoplastic origin of this lesion is debated, as cases with KRAS mutation and intra-epithelial neoplastic lesions have been recently reported. It is important to distinguish this lesion from macrocystic serous cystadenoma, mucinous cystic neoplasms and intraductal papillary mucinous neoplasms, by clinical, radiological and pathological features, as the treatment varies from simple surveillance to surgical resection.

Intramural gastric pseudocyst: A case report and a comprehensive literature review

RATIONALE

Intramural pseudocyst, although first reported several decades ago, is a rare entity. Scientific knowledge regarding its clinical management is sparse.

PATIENT CONCERNS

We present three cases to show the diverse clinical patterns of patients diagnosed with an intramural gastric pseudocyst.

DIAGNOSIS

A final diagnosis should rest on proper evaluation by cross sectional imaging, including computer tomography and magnetic resonance imaging. Endoscopic ultrasound adds to the work-up.

INTERVENTIONS

Previously, identified "lesions of the gastric wall" were not well recognized as an intramural pseudocyst, and treatments including resectional surgery were employed. Contemporary proper diagnostics should provide support to a less aggressive treatment approach.

OUTCOMES

While an indolent natural history without any clinical symptoms or discomfort could be expected in most cases, individual clinical evaluation should be applied.

LESSONS

A heterogeneous information pattern from the limited number of cases in the literature makes it difficult to draw any firm conclusions. Attention to this rare condition should be increased to help clinicians arrive at a correct diagnosis and possibly prevent some patients from being over treated or from the use of unnecessary surgery.

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.

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.

Intraductal Papillary Mucinous Neoplasm of the Pancreas Arising in the Setting of an Intermixed Acinar Cell Cystadenoma of the Pancreas: Report of a Rare Case

Background: Synchronous cystic lesions of the pancreas with different pathophysiology in the same patient are a rare occurrence..

Case Presentation: We report the incidental finding of a multicystic lesion within the pancreatic head in a morbidly obese woman during workup for bariatric surgery. The lesion contained an intraductal papillary mucinous neoplasm (IPMN) with high-grade dysplasia within an acinar cell cystadenoma (ACA). ACAs are rare tumors first described in 2002.

Conclusion: To date, there have been no published reports of synchronous IPMN within an ACA. This case report intends to increase provider awareness of these lesions as well as highlight the importance of surveillance and careful histological examination of heterogeneous cystic lesions of the pancreas.

Attempted ultrasound-guided ethanol ablation of a suspected pancreatic pseudocyst in a dog

A 9-year-old, spayed female toy poodle dog developed refractory anorexia after pancreatitis. Abdominal imaging showed a cystic structure compressing the stomach. Appetite improved after percutaneous drainage of the structure, but the structure refilled within 48 h. Percutaneous ethanol ablation of the structure was attempted. Afterwards, the patient developed fatal hypotensive shock.

A Rare Case of Epidermoid Cyst in the Pancreatic Tail Invaginated from the Splenic Hilum: The Long-term Changes in the Imaging Findings

Epidermoid cysts arising from both the pancreas and spleen are rare. We herein report a case of a surgically resected epidermoid cyst in the pancreatic tail invaginated from the spleen. A multi-locular cyst, 2 cm in diameter, without a solid component was discovered incidentally in the pancreatic tail. During the 11-year follow-up, the emergence of satellite cystic lesions with distinct appearances was seen, and surgical resection was selected despite the lack of any associated symptoms or evidence of cytological abnormalities. Histologically, these cysts were lined with benign multi-layered flattened epithelium surrounded by a thin layer consisting of cells positive for CD8 and CD68 and connecting to the spleen.

Morphological differentiation and follow-up of pancreatic cystic neoplasms using endoscopic ultrasound

Endoscopic ultrasound (EUS) is a key modality for the evaluation of suspected pancreatic cystic neoplasms (PCNs), as the entire pancreatic gland can be demonstrated with high spatial resolution from the stomach and duodenum. Detailed information can be acquired about the internal contents of the cyst(s) [septum, capsule, mural nodules (MNs)], its relation with the main pancreatic duct (MPD), and any parenchymal changes in the underlying gland. PCNs comprise true cysts and pseudocysts. True cysts can be neoplastic or nonneoplastic. Here, we describe serous cystic neoplasm (SCN), mucinous cystic neoplasm (MCN), and intraductal papillary mucinous neoplasm (IPMN) as prototype neoplastic cysts, along with nonneoplastic lymphoepithelial cysts (LECs).