Morphological imaging and CT histogram analysis to differentiate pancreatic neuroendocrine tumor grade 3 from neuroendocrine carcinoma.

PURPOSE: To compare morphological imaging features and CT texture histogram parameters between grade 3 pancreatic neuroendocrine tumors (G3-NET) and neuroendocrine carcinomas (NEC). MATERIALS AND METHODS: Patients with pathologically proven G3-NET and NEC, according to the 2017 World Health Organization classification who had CT and MRI examinations between 2006-2017 were retrospectively included. CT and MRI examinations were reviewed by two radiologists in consensus and analyzed with respect to tumor size, enhancement patterns, hemorrhagic content, liver metastases and lymphadenopathies. Texture histogram analysis of tumors was performed on arterial and portal phase CT images. images. Morphological imaging features and CT texture histogram parameters of G3-NETs and NECs were compared. RESULTS: Thirty-seven patients (21 men, 16 women; mean age, 56±13 [SD] years [range: 28-82 years]) with 37 tumors (mean diameter, 60±46 [SD] mm) were included (CT available for all, MRI for 16/37, 43%). Twenty-three patients (23/37; 62%) had NEC and 14 patients (14/37; 38%) had G3-NET. NECs were larger than G3-NETs (mean, 70±51 [SD] mm [range: 18 - 196mm] vs. 42±24 [SD] mm [range: 8 - 94mm], respectively; P=0.039), with more tumor necrosis (75% vs. 33%, respectively; P=0.030) and lower attenuation on precontrast (30±4 [SD] HU [range: 25-39 HU] vs. 37±6 [SD] [range: 25-45 HU], respectively; P=0.002) and on portal venous phase CT images (75±18 [SD] HU [range: 43 - 108 HU] vs. 92±19 [SD] HU [range: 46 - 117 HU], respectively; P=0.014). Hemorrhagic content on MRI was only observed in NEC (P=0.007). The mean ADC value was lower in NEC ([1.1±0.1 (SD)]×10-3 mm2/s [range: (0.91 - 1.3)×10-3 mm2/s] vs. [1.4±0.2 (SD)]×10-3 mm2/s [range: (1.1 - 1.6)×10-3 mm2/s]; P=0.005). CT histogram analysis showed that NEC were more heterogeneous on portal venous phase images (Entropy-0: 4.7±0.2 [SD] [range: 4.2-5.1] vs. 4.5±0.4 [SD] [range: 3.7-4.9]; P=0.023). CONCLUSION: Pancreatic NECs are larger, more frequently hypoattenuating and more heterogeneous with hemorrhagic content than G3-NET on CT and MRI.

Predisposing factors for pancreatic adenocarcinoma: What is the role of imaging?

Early detection of pancreatic adenocarcinoma is the goal of imaging, enabling curative surgery. The identification of high-grade dysplastic precursor lesions is even more beneficial. Two forms are now better known: pancreatic intraepithelial neoplasia (PanIN) and intraductal papillary mucinous neoplasm (IPMN). To detect these lesions with imaging, we need to know the patterns associated with them. A screening program could then be used to pinpoint them. This program could not be applied to the entire population. Identifying patients with an increased risk of pancreas adenocarcinoma is the first step of such screening.

Cystic form of paraduodenal pancreatitis (cystic dystrophy in heterotopic pancreas (CDHP)): a potential link with minor papilla abnormalities? A study in a large series.

OBJECTIVES: To analyze the association between cystic dystrophy in the heterotopic pancreas (CDHP) and minor papilla abnormalities. MATERIAL AND METHODS: Seventy-six patients with CDHP were retrospectively included over 14 years. Two radiologists searched for MDCT signs of CDHP (cysts and thickened intestinal wall, inflammatory changes), and minor papilla abnormalities (Santorini duct dilatation, luminal calcifications of the minor papilla). Other pancreatic abnormalities (parenchymal calcifications, main pancreatic duct dilatation) or bile duct dilatation were also analysed. RESULTS: CDHP was mostly located in the second part of the duodenum (71/76, 93.5 %). Median duodenal wall thickness was 20 mm (range 10-46). There were multiple cysts in 86 % (65/76, median = 3), measuring 2-60 mm. No cysts were identified in four patients (5 %). Inflammatory changes were found in 87 % (66/76). Minor papilla abnormalities were found in 37 % (28/76) and calcifications in the minor papilla without calcifications in the major papilla were only observed in three patients (4 %). Abnormalities of the pancreas and main bile duct dilatation were identified in 78 % (59/76) and 38 % (29/76). CONCLUSION: Previously described CT features were seen in most patients with CDHP. However, minor papilla abnormalities were seen in a minority of patients and, therefore, do not seem to be a predisposing factor for CDHP. KEY POINTS: Imaging features suggesting a CDHP diagnosis are confirmed in a large series. Minor papilla abnormalities do not seem to be a predisposing factor for CDHP. Most patients did not have any isolated minor papilla abnormalities.

Hepatic steatosis: a major trap in liver imaging.

Hepatic steatosis is a common condition, the prevalence of which is increasing along with non-alcoholic hepatic steatosis. In imaging, it can present in a typical homogeneous or heterogeneous way. Some forms create traps in imaging, whether localised steatosis is concerned or areas which have been spared by steatosis, and the purpose of this paper is to explain and illustrate them. The role of different imaging methods is described while emphasizing the importance of MRI.

Cystic and ductal tumors of the pancreas: diagnosis and management.

Incidentally discovered cystic tumors of the pancreas (CTP) are an increasingly frequent entity. It is essential to differentiate lesions whose malignant potential is either nil or negligible (pseudocyst, serous cystadenoma, simple cysts) from lesions with intermediate malignant potential (intraductal papillary mucinous tumor of the pancreas [IPMN] involving the secondary ducts, cystic endocrine tumor) or those with high malignant potential (mucinous cystadenoma, solid pseudopapillary tumors and IPMN involving the main pancreatic duct). The approach to defining malignant potential is based on diagnostic CT scan, magnetic resonance imaging (MRI), and endoscopic ultrasound (EUS), often complemented by EUS-guided cyst puncture for biochemical and cytological analysis of cyst fluid. Surgery for diagnostic purposes should be avoided because of its significant morbidity. For pseudocysts, simple cysts and serous cystadenomas, abstention is the general rule. Resection, preserving as much pancreatic parenchyma as possible, is the rule for IPMN involving the main pancreatic duct, mucinous cystadenomas, solid and pseudopapillary tumors, and cystic endocrine tumors. Resection is rarely indicated at the outset for IPMN involving secondary pancreatic ducts; morphologic observation is the general rule and preventive excision may be indicated secondarily. Good collaboration between surgeons, radiologists and endosonographists is necessary for optimal management of CTP.

Congenital portosystemic shunts associated with liver tumours.

AIM: To evaluate the diagnosis and presentation of liver tumours in patients with congenital portosystemic shunts (CPS). MATERIALS AND METHODS: Eight patients were diagnosed in Hôpital Beaujon as having CPS. All patients underwent Doppler ultrasound, computed tomography (CT), magnetic resonance imaging (MRI), and histological examination of liver tumours. CPS were classified according to anatomy and the amount of portal flow deviated to the systemic circulation as: total, subtotal, or partial. Liver tumours were diagnosed by needle core biopsy (n = 5) or surgery (n = 3). Clinical follow-up was available in all patients but one (mean follow-up 36 months; range 1-5 years). RESULTS: Six patients had total CPS, one patient had a subtotal CPS, and the last had a partial CPS. All patients presented with multiple liver nodules (range four to >15). The tumours were characterized as focal nodular hyperplasia (FNH; n = 4), FNH with hepatocellular adenoma (n = 2), and regenerative nodular hyperplasia (n = 2). In four of seven patients (57%) that had follow-up, tumours showed enlargement or new lesions appeared. CONCLUSION: In this series of CPS patients, tumours were all benign, multiple, and of hepatocellular origin, and different tumours were present simultaneously in two patients. Tumour enlargement or new nodules were common during follow-up.

Imaging IPMN: take home messages and news.

IPMN is a frequent disease involving pancreatic duct. This disease could be malignant (parenchymal invasive adenocarcinoma), particularly if the main pancreatic duct is involved (this involvement is considered present if > 6 mm), if this enlargement reaches 10 mm or more, and if the pathological phenotype is biliopancreatic or intestinal (malignancy is less frequent if gastric one). Invasiveness is suspected if hypodense parenchymal lesion is present, particularly near a cystical lesion or MPD, a mural nodule of the wall, or if MPD wall has got a contrast uptake. Mural nodules inside cystic branch duct are associated with in situ grade 3 malignancies. MPD IPMN must be resected to prevent malignancy. The follow-up of isolated branch duct cysts relies upon MDCT and MRI, every two years if lesion is less than 1cm. Every one year if bigger, particularly if more than to 3 cm.

[Peritoneal parasitic teratoma and chemical dermoid peritonitis]. / Tératomes parasitiques péritonéaux et péritonites chimiques dermoïdes.

Chemical peritonitis occurs following intraperitoneal rupture of a mature ovarian dermoid. Rupture may be acute and spontaneous, typically during pregnancy, or iatrogenic. Low grade ruptures lead to parasitic peritoneal dermoid cysts, usually involving the greater omentum, cul-de-sac of Douglas and perihepatic region. Radiologists should be familiar with their appearance to correctly diagnose the condition and not mistake the disease for peritoneal carcinomatosis.

Hepatocellular carcinoma--what's new?

The increasing incidence of hepatocellular carcinoma (HCC) has led several countries to standardize and update its management. This review aims at summarizing these evolutions through six questions focusing on diagnosis and treatment. The radiological diagnosis of this tumor has been refined. Besides being hypervascular at the arterial phase, the "washout" in particular at the late phase of injection has become a prominent feature. Although routine ultrasound remains the corner stone of screening, contrast ultrasound has become a very reliable characterization tool as it allows continuous monitoring of the vascular kinetics. Biopsy of the tumor allows identification of conventional or molecular prognosis features, some of which could be used in current practice. The metabolic syndrome is an increasing etiology of HCC and carcinogenesis in this context may not always require the development of formal underlying cirrhosis. Associated (in particular cardiovascular) conditions account for an increased morbidity-mortality following surgery. Liver transplantation is the most effective treatment of early-stage tumors. The limited availability of grafts has led some countries including France to implement new allocation rules that are still evaluated and might need to be refined. Sorafenib is the first medical treatment shown to be effective in the treatment of HCC. This efficacy is however still limited and its indication is therefore restricted to Child-Pugh A, OMS 0-2 patients in whom a potentially curative treatment is contraindicated.

[Postoperative imaging of the peritoneum and abdominal wall]. / Imagerie post-opératoire du péritoine et de la paroi abdominale.

CT scan is the gold standard for follow-up after abdominal surgery and diagnosis of postoperative complications. During the immediate postoperative period, asymptomatic and rapidly regressing peritoneal collections of fluid and gas are often present. Transient ileus is classically present as well. The diagnosis of postoperative peritonitis is difficult on imaging; fluid collections are frequent and easily detected. The main postoperative peritoneal complication is small bowel obstruction, either early and due to inflammatory changes, or delayed and due to adhesions or less frequently to other causes, including transmesenteric hernia. Other rare complications include desmoid tumors and gossypiboma. Wall complications, after laparotomy as well as laparoscopic surgery, are mainly hematoma, infections and wound hernia.

[Diagnosis and follow-up of small intraductal papillary mucinous neoplasm of the pancreas]. / Diagnostic d'une petite tumeur intracanalaire papillaire et mucineuse du pancréas et surveillance.

Intraductal papillary mucinous tumours are diagnosed more and more often fortuitously. Initial work-up relies on CT scan, CP-MRI and endoscopic ultrasound of excellent technical quality. Their aspect might be extremely proteiform. They usually appear as cystic lesion, unique or multiple, localized or diffuse, involving main or branch pancreatic duct. The communication between the cystic lesion and the ductal system is essential for diagnosis. If main pancreatic duct is not involved and in absence of mural nodules, it is recommended not to resect them and to initiate follow-up. The follow-up examination relies on CP-MRI and, in case of symptomatic or imaging modifications, on endoscopic ultrasound. The interval between follow-up examinations remains to be determined. In case of imaging change might lead to resection.

Are pancreatic calcifications specific for the diagnosis of chronic pancreatitis? A multidetector-row CT analysis.

AIM: To retrospectively establish the most frequently encountered diagnoses in patients with pancreatic calcifications and to investigate whether the association of certain findings could be helpful for diagnosis. MATERIALS AND METHODS: One hundred and three patients were included in the study. The location and distribution of calcifications; presence, nature, and enhancement pattern of pancreatic lesions; pancreatic atrophy and ductal dilatation were recorded. Differences between patients with chronic pancreatitis and patients with other entities were compared by using Fisher's exact test. RESULTS: Patients had chronic pancreatitis (n=70), neuroendocrine tumours (n=14), intraductal papillary mucinous neoplasm (n=11), pancreatic adenocarcinoma (n=4), serous cystadenoma (n=4). Four CT findings had a specificity of over 60% for the diagnosis of chronic pancreatitis: parenchymal calcifications, intraductal calcifications, parenchymal atrophy, and cystic lesions. When at least two of these four criteria were used in combination, 54 of 70 (77%) patients with chronic pancreatitis could be identified, but only 17 of 33 (51%) patients with other diseases. When at least three of these four criteria were present, a specificity of 79% for the diagnosis of chronic pancreatitis was achieved. CONCLUSION: Certain findings are noted more often in chronic pancreatitis than in other pancreatic diseases. The presence of a combination of CT findings can suggest chronic pancreatitis and be helpful in diagnosis.

Clinical and imaging follow-up after exhaustive liver resection of endocrine metastases: a 15-year monocentric experience.

Liver metastases are common in gastroenteropancreatic neuroendocrine tumors and significantly impair survival. Hepatic resection is the only potential curative treatment. The records of 41 consecutive patients undergoing exhaustive resection of liver-only endocrine metastases and followed between 1992 and 2006 were reviewed. Patient's outcome and diagnostic accuracy of somatostatin receptor scintigraphy (SRS) and morphological imaging (MI) for detection of recurrences during post-operative follow-up were assessed. All identified primary had been resected. MI studies including abdominal computed tomography (CT) and/or liver magnetic resonance imaging and thoracic CT if indicated were performed every 6 months; SRS timing was decided by referring clinician. Tumor recurrences were confirmed by pathology or subsequent imaging studies. The results of 136 MI and SRS examinations performed within a 30-day interval from each other were retrospectively compared. Median post-operative follow-up was 51 months (7-165). Recurrences developed in 32 patients (78%), mainly in the liver (n=24) after a median of 19 months (2-79). Five-year overall and disease-free survival rates were 79 and 3% respectively. For recurrence detection, sensitivity, specificity, and accuracy were 89, 94, and 91% for SRS, 68, 91, and 74% for MI respectively. In 11 out of 32 patients (34%), abdominal or extra-abdominal metastases were detected 15.5 months earlier by SRS than MI. In conclusion, despite exhaustive liver surgery for endocrine metastases, hepatic or extra-hepatic recurrences are frequent and develop early. SRS is highly accurate for the detection of recurrences during post-operative follow-up and permitted early diagnosis in one third of patients; therapeutic implications of this early diagnosis remain to be determined.

[Limited pancreatic resections for intraductal papillary mucinous neoplasm]. / Résections limitées du pancréas pour tumeur intracanalaire papillaire et mucineuse non invasive.

INTRODUCTION: For non-invasive intraductal papillary and mucinous neoplasm (IPMN) with limited extent, pancreaticoduodenectomy (PD) or distal pancreatectomy (DP) seem excessive due to the risk of pancreatic insufficiency. Enucleation (EN) or medial pancreatectomy (MP) are not commonly performed for IPMN. The aim of this study was to evaluate the feasibility and results of EN and MP for non-invasive IPMN. PATIENTS AND METHODS: Of 249 patients with IPMN, we attempted a limited resection in 50 (20%) EN (n=31) or MP (n=20) with routine intra-operative frozen section pathology. One attempted EN was converted to MP. Indications for surgery were pain/pancreatitis (44%), suspicion of main duct involvement (28%), mural nodules in branch duct (14%), branch duct>30 mm (8%) or suspicion of mucinous cystadenoma (6%). Follow-up clinical assessment and MRI were performed on a yearly basis. RESULTS: Of the 31 attempted enucleations, 5 (13%) were immediately converted (4 PD, 1 MP) due to technical reasons (n=3) or due to findings on frozen section (n=2). At definitive pathological examination (accuracy of frozen sectioning=98%), branch ducts were involved by mild (n=21), moderate (n=7) or high grade dysplasia (n=2). One patient underwent a double EN. Of 20 attempted medial pancreatectomies, 8 (40%) required additional segmental resection due to significant IPMN lesions at pancreatic margins; 3 of the additional resection margins were tumor-free, and 5 were involved by IPMN (4 conversions to PD or DP, one contra-indication to PD). Overall, 49 pancreatic margins were analyzed by frozen sectioning with 98% accuracy. Resected specimens of 16 MP showed involvement by mild (n=7), moderate (n=7) or high grade dysplasia (n=2). There was no postoperative mortality. Median length of stay was 21 and 30 days respectively after EN and MP. Pancreatic fistula rate was 54% and 81% respectively after EN and MP. Three patients underwent early re-operation for hemorrhage. Overall median follow-up was 24 months (3-121). All patients are alive, 2 patients (5%) have presented with recurrent pain and 4 have developed tumor recurrence on imaging follow-up (4/33=12%). Two patients (5%) developed de novo diabetes (one after EN combined with DP) and a third patient developed worsening of pre-existing diabetes plus exocrine insufficiency. No patient had surgery for recurrence. CONCLUSIONS: EN and MP are feasible for non-invasive IPMN. Their significant early morbidity is counterbalanced by low rates of both long-term functional disorders and tumor recurrence.

Cystic dystrophy in gastric heterotopic pancreas complicated by intracystic hemorrhage and fistulisation in the stomach - a pediatric case.

CONTEXT: Cystic dystrophy of the digestive wall, a rare but well-known complication of heterotopic pancreas when it is located in the duodenum, has been mainly described in adult series. Cystic dystrophy of the heterotopic pancreas within the gastric wall has been reported in only six adult cases. To our knowledge, no pediatric case has been described. CASE REPORT: We report a 15-year-old boy surgically treated for cystic dystrophy located in the antrum, complicated by an intracystic hemorrhage and fistulisation into the stomach. CONCLUSION: The diagnosis of heterotopic pancreas must be considered in case of submucosal cystic-gastric lesions, even in pediatric cases. Although the surgical approach is not systematic, it is recommended when cystic dystrophy is symptomatic (e.g., occlusion or hemorrhage).

[Liver imaging: pitfalls, pseudolesions and pseudotumors]. / Imagerie hépatique: pièges, pseudolésions et pseudotumeurs.

Recognition of pseudolesions of the liver at imaging is important because of their close resemblance to primary liver cancer or metastases. There are several types of pseudolesions: pseudolesions, with mostly straight borders, corresponding to perfusion abnormalities, fatty liver, confluent fibrosis and radiation hepatitis; morphologic changes of the liver; true pseudotumors. The use of multidetector CT and MR imaging increases the likelihood of detecting such lesions in routine practice. Radiologists must recognize these lesions and understand the underlying etiology.

[MR imaging of the pancreas]. / IRM et maladies pancréatiques.

Magnetic resonance (MR) imaging of the pancreas has undergone a major change because it can provide noninvasive images of the pancreatic ducts and the parenchyma. MR cholangiopancreatography (MRCP) enables detection of anatomic variants such as pancreas divisum. Although contrast material-enhanced CT is still considered the gold standard in acute pancreatitis and for the detection of calcifications in chronic pancreatitis, MR imaging and secretin-enhanced MRCP are useful in evaluating pseudocysts and pancreatic disruption. The role of MR is still debated in pancreatic neoplasms except the cystic lesions where MR imaging provides critical information regarding the lesion's content and a possible communication with the pancreatic ducts. MRCP and MR of the pancreas are also useful in identifying other pancreatic diseases such as lymphoplasmocytic pancreatitis and groove pancreatitis.

Arterial phase enhancement and body mass index are predictors of response to chemoembolisation for liver metastases of endocrine tumours.

Transcatheter arterial chemoembolisation (TACE) has been reported to be an efficient treatment of liver metastases of endocrine tumours in short series of patients. However, several factors seem to affect its results. The aim of this work is to identify predictors of response to TACE for liver metastases of endocrine tumours. A total of 163 TACE procedures were performed in 67 patients between 1994 and 2004. Forty-four patients were treated with streptozotocin and 23 with doxorubicin. Primary tumour was located in the pancreas for 19 patients, and had been removed in 43. Thirty-eight tumours were functioning. Response rate was 37% (confidence interval [CI] 95%: 28-49%). Median time to progression (TTP) was 14.5 months (CI 95%: 9-41). In multivariate analysis (n=43), predictors of tumour response were body mass index (BMI) (odds ratio [OR]: 1.3; CI 95%: 1.04-1.63; P=0.022), functioning type of tumour (OR: 7.31; CI 95%: 1.26-42.5; P=0.027), arterial phase enhancement on abdominal computed tomography (CT) (OR: 8.11; CI 95%:1.06-62; P=0.044) and use of streptozotocin for cytotoxic agent (OR: 21.3; CI 95%: 1.48-306; P=0.025). Analysis of TTP predictors showed that BMI (hazard ratio [HR]: 0.85; CI 95%: 0.76-0.86; P=0.01) and arterial phase enhancement (HR: 0.3; CI 95%: 0.12-0.73; P=0.008) were associated with delayed progression. This large study confirms the previously reported results of TACE regarding its efficacy for the treatment of liver metastases of endocrine tumours. Arterial phase enhancement on abdominal CT and BMI are predictors of treatment's efficacy. Streptozotocin should be the preferred cytotoxic agent in order to save anthracycline for systemic chemotherapy.

[Isolated or multifocal segmental intrahepatic bile duct dilatation: management]. / Une dilatation segmentaire uni ou pluri-focale des voies biliaires intra-hépatiques à l'échographie. Quelle conduite à tenir?

Segmentary dilatation of intrahepatic bile ducts are well depicted with ultrasound. Two groups of diseases could be differentiated by searching a liver mass: biliary diseases without any tumor or dilatation of biliary duct due to an adjacent liver mass. Inside these two groups, some diseases are frequent and other not. We will emphasize autoimmune cholangitis and (Low Phospholipid Associated Cholelithiasis) LPAC with MDR3 deficiency. Decisional trees are proposed.