Unusual imaging appearances of pancreatic serous cystadenoma: correlation with surgery and pathologic analysis

Giant serous cystadenoma of the pancreas appearing sonographically as a remote pararenal mass

Macrocystic serous cystadenoma (MSC) of the pancreas is a rare benign neoplasm with varied imaging appearances. We describe an intriguing case of a surgically resected and histologically proven giant MSC, developed in the pararenal space. Ultrasonography (US) revealed a large, oligocystic mass around the lower pole of right kidney. Like US, computed tomography, and magnetic resonance imaging were unable to detect the origin of the lesion, which was only verified at surgical exploration. A bizarre finding was the unusual location of the pancreatic tumor growing seemingly apart from the pancreas itself, with no obvious connection to it.

Pseudo solid-appearing pancreatic serous microcystic adenomas: Histologic diagnosis with the EUS core biopsy fork-tip needle

Background and Objectives:

Despite rarely, serous cystic adenoma (SCA) can assume a pseudo-solid aspect mimicking other pancreatic neoplasm as neuroendocrine tumor. EUS-FNA cytology has low diagnostic accuracy due to the scant cellularity of the collected samples. Histological diagnosis is usually made after resection. Recently, end-cutting needles for EUS-fine-needle biopsy (EUS-FNB), which obtain tissue cores by penetrating the lesions, have been developed. We aimed to assess the capability of EUS-FNB with SharkCore™ needles in the preoperative diagnosis of serous cystic adenoma pseudo-solid-appearing on imaging (Sa-SCA).

Materials and Methods:

Between January 2016 and January 2018, data from consecutive adult patients, who were referred for EUS-FNB of a solid pancreatic lesion and were diagnosed with having SCA, were retrieved from a single-center institutional database.

Results:

Two patients were excluded because of microcystic aspect at EUS. Histological diagnosis of SCA was made by EUS-FNB in the remaining 7 patients (5 females; mean age of 62.5 years). Lesions (mean size of 19.8 mm) were hypervascular on cross-sectional imaging, slightly hyperdense magnetic resonance imaging with T2-weighted images can, and negative at ⁶⁸Ga-somatostatin receptor positron emission tomography and ¹⁸fluoro-deoxyglucose positron emission tomography. EUS-FNB samples were judged adequate for a definitive diagnosis in all cases, achieving specimens suitable for histological evaluation and several ancillary stains. Histochemical positivity for periodic acid-Schiff (PAS) and PAS with diastase digestion was observed in 7/7 cases. Immunohistochemical positivity for α-inhibin (7/7), GLUT1 (6/6), MUC6 (5/5), and negativity for synaptophysin (7/7) and chromogranin A (2/2) favored SCA diagnosis.

Conclusions:

In the case of preoperative workup suspected for Sa-SCA, a “forward acquiring” needle could improve the rate of preoperative histological diagnosis.

Potential value of EUS in pancreatic surveillance of VHL patients

BACKGROUND

Patients with von Hippel-Lindau (VHL) disease are prone to develop pancreatic neuroendocrine tumors (pNETs). However, the best imaging technique for early detection of pNETs in VHL is currently unknown. In a head-to-head comparison, we evaluated endoscopic ultrasound (EUS) and (11)C-5-hydroxytryptophan positron emission tomography ((11)C-5-HTP PET) compared with conventional screening techniques for early detection of pancreatic solid lesions in VHL patients.

METHODS

We conducted a cross-sectional, prospective study in 22 patients at a tertiary care university medical center. Patients with VHL mutation or with one VHL manifestation and a mutation carrier as first-degree family member, with recent screening by abdominal computed tomography (CT) or magnetic resonance imaging (MRI) and somatostatin receptor scintigraphy (SRS), were eligible. Patients underwent EUS by linear Pentax echoendoscope and Hitachi EUB-525, and (11)C-5-HTP PET. Patient-based and lesion-based positivity for pancreatic solid lesions were calculated for all imaging techniques with a composite reference standard.

RESULTS

In 10 of the 22 patients, 20 pancreatic solid lesions were detected: 17 with EUS (P < 0.05 vs CT/MRI+ SRS), 3 with (11)C-5-HTP PET, 3 with SRS, 9 with CT/MRI, and 9 with CT/MRI + SRS. EUS evaluations showed solid lesions with a median size of 9.7 mm (range 2.9-55 mm) and most of them were homogeneous, hypoechoic, isoelastic, and hypervascular. Moreover, EUS detected multiple pancreatic cysts in 18 patients with a median of 4 cysts (range 1-30).

CONCLUSIONS

EUS is superior to CT/MRI + SRS for detecting pancreatic solid lesions in VHL disease.(11)C-5-HTP PET has no value as a screening method in this setting. EUS performs well in early detection of pNETs, but its role in VHL surveillance is unclear.

Differentiation of solid-type serous cystic neoplasm from neuroendocrine tumour in the pancreas: value of abdominal MRI with diffusion-weighted imaging in comparison with MDCT

AIM

To evaluate the value of abdominal MRI with diffusion-weighted (DW) imaging for differentiation of solid-type serous cystic neoplasm (SCN) from neuroendocrine tumour (NET) in the pancreas compared with that of CT.

MATERIALS AND METHODS

Ten solid-type SCNs and 15 NETs were included in the study. Qualitative and quantitative analyses were performed, and two observers independently reviewed CT and MRI images for diagnosis of solid-type SCNs. Fisher's exact test and Mann-Whitney U-test, diagnostic performance [receiver operating characteristic (ROC) curve analysis] were evaluated.

RESULTS

SCNs showed more frequently hypo-attenuation on unenhanced CT images and marked hyperintensity on T2-weighted images compared with NETs (p < 0.01). The density of the tumour on unenhanced CT images and the apparent diffusion coefficient (ADC) value of the tumour were significantly different between SCNs (mean 18.5 HU; mean 2.45 × 10(-3) mm(2)/s) and NETs (mean 39.2 HU; mean 1.51 × 10(-3) mm(2)/s; p < 0.001). In the differentiation of SCNs from NETs, diagnostic performance of MRI with DW images was significantly higher than that of CT imaging (p < 0.01).

CONCLUSION

Abdominal DW-MRI shows a higher diagnostic accuracy than abdominal CT imaging in the differentiation of solid-type SCNs from NETs.

State-of-the-art PET/CT of the pancreas: current role and emerging indications

Fused positron emission tomography (PET)/computed tomography (CT) is a recently developed technology that couples the functional information of PET with the anatomic details of CT. Integrated PET/CT scanners produce both PET and contrast material-enhanced CT images of the entire body in one setting. Typically, the amount of fluorine 18 (18F) fluorodeoxyglucose (FDG) uptake in normal pancreatic parenchyma is insignificant compared with that of the liver. However, both malignant (eg, adenocarcinoma) and benign (eg, acute pancreatitis) pancreatic conditions may demonstrate intense FDG uptake. PET/CT provides an opportunity to depict pancreatic tumors and distant metastases, perform preoperative staging, and monitor response to treatment, and it has proved useful in distinguishing postoperative fibrosis from recurrence. In selected cases, PET/CT findings may be used to help diagnose autoimmune pancreatitis mimicking a mass by depicting systemic involvement. PET/CT may also be used to direct biopsy to sites more likely to yield representative tumor tissue. Novel radiolabeled molecules, such as sigma-receptor ligands and 18F-3'-fluoro-3'-deoxy-l-thymidine (FLT), may play an even greater role in distinguishing tumor recurrence from postoperative fibrosis or inflammation.

Cystic tumors of the pancreas: imaging and management

Cystic tumors of the pancreas are a subset of rare pancreatic tumors that vary from benign to malignant. Many have specific imaging findings that allow them to be differentiated from each other. This article (1) reviews the imaging features of the common cystic pancreatic lesions, including serous microcystic adenoma, mucinous cystic tumor, intraductal papillary mucinous tumor, and solid pseudopapillary tumor, and including the less common lesions such as cystic endocrine tumors, cystic metastases, cystic teratomas, and lymphangiomas; and (2) provides comprehensive algorithms on how to manage the individual lesions, with recommendations on when to reimage patients.

CT imaging spectrum of pancreatic serous tumors: based on new pathologic classification

PURPOSE

The aim of this study is to retrospectively analyze the variety of CT findings based on new pathologic classification.

MATERIALS AND METHODS

During a 10-year period, 59 histopathologically proven pancreatic SCTs and 13 SCTs confirmed with typical image findings and strict clinical criteria were enlisted. Two radiologists analyzed CT images for the following items in consensus: location, size, outer margin, tumor shape, the presence of mural nodule, communication with main pancreatic duct (MPD), the presence and extent of MPD dilatation, calcification, central scar, and attenuation on pre- and post-contrast CT images. In addition, typicality of CT findings was determined. A typical finding was defined as a honeycomb appearance without or with oligocystic portion. In the cases with atypical features, the type of atypical features and differential diagnosis were recorded. For the shape of the tumor, tumors were categorized into the following groups: honeycomb without or with oligocystic, pleomorphic, purely oligolocular, unilocular cystic, hypovascular solid, hypervascular solid without or with oligocystic portion, and fingerlike cystic patterns.

RESULTS

28 SCTs (38.9%) presented a honeycomb appearance with (n=14) or without oligocystic portion (n=14) and were classified as typical cases. The remaining 44 atypical cases (61.1%) presented the following: purely oligolocular pattern in 18; hypervascular solid without (n=7) or with oligocystic portion (n=2) in 9; pleomorphic in 8; unilocular cystic in 7; and fingerlike cystic pattern in 2. Most of the lesions manifesting as hypervascular solid lesions were confused with true solid hypervascular tumors such as neuroendocrine tumors or solid pseudopapillary tumors. For most of the remaining atypical lesions, mucinous cystic neoplasm or branch duct type IPMN were included as a differential diagnosis.

CONCLUSION

Serous cystic tumors of the pancreas can have variable CT appearances ranging from compactly solid hypervascular to clearly unilocular cystic, which reflect a varied macroscopic morphology. Only 38.9% of the SCTs show traditional typical CT features whereas a considerable proportion (61.1%) of SCTs showed atypical appearances, providing diagnostic challenges to radiologists.

Typical and atypical manifestations of serous cystadenoma of the pancreas: imaging findings with pathologic correlation

OBJECTIVE

The purpose of this article is to present the typical and atypical manifestations of serous cystadenoma, which can be visualized with cross-sectional imaging.

CONCLUSION

Serous cystadenomas of the pancreas have various distinguishing imaging features. Typically, a serous cystadenoma is morphologically classified as having either a polycystic, honeycomb, or oligocystic pattern. Atypical manifestations of serous cystadenoma can include giant tumors with ductal dilatation, intratumoral hemorrhages, solid variants, unilocular cystic tumors, interval growth, and a disseminated form.

Three cases of serous oligocystic adenomas of the pancreas; evaluation of cyst wall thickness for preoperative differentiation from mucinous cystic neoplasms

BACKGROUND

Serous oligocystic adenoma (SOA), a rare pancreatic neoplasm, is generally a benign lesion without the necessity of surgery. Preoperatively, it is difficult to discriminate SOA from mucinous cystic neoplasm (MCN), which essentially needs surgical treatment. The purpose of this study was to evaluate the cyst wall thickness of SOAs and MCNs for preoperative differential diagnosis.

METHODS

We experienced three cases of SOAs with typical histopathological features. The cyst wall thickness of the SOAs was evaluated in the area protruding out of the pancreas and was compared with that of 13 MCNs histopathologically. The same evaluation and comparison were conducted on preoperative computed tomography (CT) images retrospectively.

RESULTS

The SOAs had a uniformly thin cyst wall measuring less than 1 mm. In contrast, the largest area of a cyst wall in MCNs ranged from 2.5 to 10.0 mm. On CT images, all but one of the MCNs showed a detectable cyst wall, while the cyst walls were hardly recognizable in two of the three SOAs.

CONCLUSIONS

For preoperative differentiation between SOAs and MCNs, the evaluation of cyst wall thickness may be an important tool and may contribute to the decision of treatment strategy.

Pancreatic cystic lesions: discrimination accuracy based on clinical data and high-resolution computed tomographic features

OBJECTIVE

To determine the frequency of typical features of pancreatic cystic lesions on high-resolution computed tomography and the combination of features that best influences discrimination.

METHODS

Ten computed tomography features of 100 proven pancreatic cystic lesions were retrospectively tabulated by 2 blinded imagers. After final diagnosis was revealed, each lesion was categorized as typical or atypical. Stepwise multivariable logistic regression was used to determine which of 10 imaging and 4 clinical features significantly distinguished between benign and malignant lesions.

RESULTS

There were 38 benign cysts and 62 cystic tumors. Serous lesions presented with greater than 6 cysts (83%) and cysts of less than 2 cm (44%). Mucinous lesions presented with cysts of 2 cm or greater (82%) and less than 6 cysts (64%). Pseudocysts, serous, and mucinous lesions presented typically in 77%, 67%, and 64% of cases, respectively. The significant variables in classifying malignant lesions are pancreatitis history, cyst size, symptoms, and calcification pattern (area under the curve, 0.837).

CONCLUSIONS

Four specific imaging and clinical features in combination best predict a malignant lesion.

Quantitative preoperative assessment of vascular involvement in pancreatic carcinoma by multi-detector row computer tomography

AIM: To evaluate the clinical efficacy of multi-detector row computer tomography (MDCT) in the preoperative quantitative assessment of vascular involvement of pancreatic carcinoma.

METHODS: MDCT was performed on 42 pancreatic carcinoma patients; the celiac trunk and portal vein were reconstructed and their branches to three-dimension vessel were analyzed by volume rendering (VR) technique, multiplanar volume reconstruction (MPVR) and maximum intensity projection (MIP) technique. Combining the source images, the scope and extent of the vessel invaded in the portal vein celiac trunk, and inferior vena cava and their branches were evaluated and measured. Compared the CT scans results with operations and pathological sections, the diagnosis value of MDCT for pancreatic carcinoma was evaluated.

RESULTS: In the 42 pancreatic carcinoma patients with operation, 252 vessels were evaluated, 77 of which were invaded by carcinoma. Celiac trunks were invaded in 12 patients, and the sensitivity and specificity were 84.6% and 96.6%, respectively. Superior mesenteric arteries were invaded in 13 patients, and the sensitivity and specificity were 100% and 96.7%, respectively. Hepatic arteries were invaded in 9 patients, and the sensitivity and specificity were 81.2% and 100%, respectively. Portal veins were invaded in 16 patients, and the sensitivity and specificity were 93.3% and 92.6%, respectively. Inferior vena cava was invaded in 6 patients, and the sensitivity and specificity were 93.3% and 92.6%, respectively. Superior mesenteric veins were invaded in 21 patients, and the sensitivity and specificity were 90% and 86.7%, respectively. In the aspect of thrombosis, MDCT scan results were consistent with the surgical findings. Only one vessel of superior mesenteric artery and vein was not correctly measured in length by MDCT. When the length between invaded vessel and vessel branches was measured, only one patient's MDCT result was consistent with the surgical result on superior mesenteric artery.

CONCLUSION: MDCT can delineate the vascular involvement of pancreatic carcinoma with high accuracy, measure the invaded vessel correctly and provide valuable information for the preoperative assessment of pancreatic carcinoma.

CT of serous cystadenoma of the pancreas and mimicking masses

OBJECTIVE

The purpose of this article is to illustrate the varied CT appearances of serous cystadenoma of the pancreas and of masses that mimic serous cystadenoma.

CONCLUSION

Serous cystadenomas of the pancreas have a wide range of CT findings. Familiarity with the varied CT appearances and awareness of the diagnostic limitations of CT are important for accurate diagnosis and management of serous cystadenoma of the pancreas.

The Spectrum of Cystic Masses of the Pancreas: Imaging Features and Diagnostic Difficulties

Cystic masses of the pancreas comprise a diverse group of pathologic entities ranging from pseudocysts to cystic tumors. Although their presentations may be similar, the appropriate treatment and patient management can differ greatly. There is an overlap in radiologic features, but the clinical context and some imaging findings are useful in differentiating among these entities; the differential diagnosis could be considerably reduced and it is generally possible to reach the correct diagnosis. In this article, we review imaging characteristics and radiologic patterns of both common and uncommon cystic masses of the pancreas. An algorithmic approach for the management of cystic pancreatic lesions is proposed.