Imaging and localization of islet-cell tumours of the pancreas on CT and MRI

Nonfunctioning Pancreatic Endocrine Neoplasm Presenting as Asymptomatic, Isolated Pancreatic Duct Stricture: A Case Report and Review of the Literature

Morphologic irregularities of the pancreatic duct are often noted on abdominal imaging studies obtained for unrelated symptoms or conditions. We report the case of a patient who was found to have an incidental, isolated pancreatic duct dilatation on multiple imaging studies and who was found to have a nonfunctioning pancreatic endocrine neoplasm at resection. His prognosis is excellent based on the histology of the lesion and a curative resection. This case highlights the importance of fully investigating incidental pancreatic duct abnormalities regardless of the setting in which they are found.

Uncommon solid pancreatic neoplasms: ultrasound, computed tomography, and magnetic resonance imaging features

This article reviews the ultrasound, computed tomography, and magnetic resonance imaging features of rare solid tumors of the pancreas with attention to distinctive imaging appearances, which can help radiologists to discriminate between the different entities. Various uncommon solid pancreatic neoplasms, including exocrine and endocrine epithelial tumors, mesenchymal tumors, and metastases, are reviewed, with emphasis on key differential points, including morphologic features and patterns of contrast enhancement.

Arterial vs pancreatic phase: which is the best choice in the evaluation of pancreatic endocrine tumours with multidetector computed tomography (MDCT)?

PURPOSE

The aim of this study was to assess whether the pancreatic phase may replace the arterial phase in the evaluation of endocrine pancreatic tumours.

MATERIALS AND METHODS

Twenty-nine endocrine pancreatic lesions with definitive morphological and immunohistochemical characterisation after surgical treatment (n=24) or fine-needle-aspiration cytology under endoscopic ultrasonography guidance (n=5) were retrospectively evaluated. All lesions were studied with triple-phase 16-row multidetector computed tomography (MDCT). Images obtained during each phase were separately interpreted by two senior radiologists experienced in pancreatic pathology and who were blinded to surgical results. Endocrine tumour and normal pancreas attenuation and the mean absolute tumour-to-gland attenuation difference were measured in each phase, and data were analysed with Student's t test. Visualisation of arterial vascular abnormalities and hypervascular liver metastases in the arterial and pancreatic phases and the diagnostic contribution of the two phases were compared.

RESULTS

For both radiologists, the mean absolute tumour-to-gland attenuation difference was significantly higher (p<0.05) in the pancreatic phase (40+/-53 HU and 34+/-56 HU) than in the arterial phase (31+/-38 HU and 26+/-43 HU). There were no differences in the detection of arterial vascular abnormalities or hypervascular liver metastases in the two phases. The diagnostic contribution was higher in the pancreatic phase.

CONCLUSIONS

In our experience, the pancreatic phase can replace the arterial phase in the evaluation of pancreatic endocrine tumours.

Imaging of neuroendocrine tumors

Neuroendocrine tumors may arise from a wide range of organs and may occur in various locations in the body. They include carcinoid tumors, paragangliomas (pheochromocytomas), medullary thyroid carcinomas, and islet cell tumors of the pancreas. In this article the authors focus on the more common tumors with origins primarily in the abdomen, namely carcinoid, paraganglioma, and pancreatic islet cell tumors. Imaging assists in delineating the sites and extent of disease, in preoperative planning for resection of the primary tumor and metastatic disease, and in follow-up. Discussion is restricted to the main imaging modalities used in these tumors: cross-sectional imaging, namely CT and MRI, and nuclear medicine studies.

Accessory spleen presenting as a mass in the tail of the pancreas

In this case report, we describe an accessory spleen that presented as a mass in the tail of the pancreas and mimicked a neoplasm. Intrapancreatic accessory spleen have a relatively high prevalence and can be mistaken for tumors. We present a case of intrapancreatic accessory spleen in a 40-year-old man, which was discovered incidentally during a workup for an aortic dissection. Computerized axial tomography and magnetic resonance imaging scans demonstrated a hypervascular mass in the tail of the pancreas. The clinical and radiological differential diagnosis included pancreatic mucinous cystic neoplasm, pancreatic endocrine neoplasm, solid pseudopapillary tumor, ductal adenocarcinoma, and metastasis. After a distal pancreatectomy was completed, microscopic examination revealed heterotopic splenic tissue.

Islet Cell Carcinoma: Neuroendocrine Tumors of the Pancreas and Periampullary Region

Most patients who have islet cell tumors, except those who have insulinomas, present with locally advanced or metastatic disease. In contrast with patients who have adenocarcinoma of the pancreas, those who have islet cell carcinomas can achieve long-term survival even if their disease is advanced. Liver-directed therapies, somatostatin analogs, and interferon are not curative but can be used to relieve tumor-associated symptoms. Similarly, palliative chemotherapy has been used with limited success. Advances in our understanding of the molecular mechanisms underlying tumor progression have translated into intense interest in biologically based strategies to treat this disease.

CT and MR imaging findings of endocrine tumor of the pancreas according to WHO classification

The pancreatic endocrine tumors are rare neuroendocrine tumors of the pancreas originating from totipotential stem cells or differentiated mature endocrine cells within the exocrine gland. Endocrine tumors are usually classified into functioning and non-functioning tumors and presents with a range of benignity or malignancy. In this article, we present the various CT and MR imaging findings of endocrine tumors of pancreas according to recent WHO classification.

Single-photon emission computed tomography/computed tomography in endocrinology

The introduction of fusion of functional and anatomical imaging modalities into the field of endocrinology led to a major breakthrough in diagnosis, staging, and follow-up of patients with endocrine tumors. The management of endocrine tumors is based on a wide variety of conventional techniques, including computed tomography, ultrasound, or magnetic resonance imaging, and on scintigraphic functional techniques, associated with unique uptake and transport mechanisms and with the presence of high density of membrane receptors on some of these tumors. Anatomical modalities provide accurate detection and localization of morphological abnormalities, whereas nuclear medicine studies reflect the pathophysiological status of the disease process. Lack of structural delineation and relatively low contrast hamper the precise anatomical localization of the abnormal functional findings in the presence of potential concurrent foci related to the physiological biodistribution of the radiotracer or to processes unrelated to the evaluated disease entity. The notion that anatomical high-resolution and functional imaging data act as complementary methods led to various combination techniques of these modalities. However, coregistration of the functional and anatomical data after the acquisition of the 2 imaging modalities on separate machines, in different sessions, fails to provide accurate alignment of data, and the mathematical modeling is too cumbersome to be used on a routine basis. In contrast, hybrid imaging devices of single-photon emission computed tomography/computed tomography in a single gantry enable the sequential acquisition of the two modalities, with subsequent merging of data into a composite image display. These hybrid studies have led to a revolution in the field of imaging, providing clinically relevant information that is not apparent on separate images. The present review evaluates the contribution of the integrated single-photon emission computed tomography/computed tomography technology to image analysis and management of patients with endocrine tumors.

Minimally invasive pancreatic surgery: the new frontier?

Recent advances in minimally invasive pancreatic surgery encompass laparoscopic, retroperitoneoscopic, endoscopic, thoracoscopic, and percutaneous approaches. Applications of endoscopic pancreatic surgery include laparoscopic resection, necrosectomy, drainage of pseudocysts, gastric and biliary bypass, and thoracoscopic splanchnotomy. This review provides an update on laparoscopic pancreatic resections. Over 400 cases of laparoscopic distal pancreatectomy (LDP) and enucleation (LEn) have been reported in the English literature, largely for benign disease. LDP and LEn have been associated with reductions in blood loss, morbidity, and hospital stay and a greater rate of splenic preservation compared with open surgery. Laparoscopic ultrasound is essential for intraoperative localization of insulinomas because failure of localization is the most common cause for conversion to laparotomy. The role of LDP with en bloc splenectomy and laparoscopic pancreaticoduodenectomy (LPD) for malignancy remains controversial. The majority of LPDs have been performed for malignancy. The short-term results of the limited world experience of 34 reported LPDs appear favorable.