The purpose of the present study is to evaluate whether an online reference system (ORS, STATdx Elsevier, Amsterdam, Netherlands) impacts finding the histologically confirmed diagnosis of rare or atypical abdominal tumors and lesions in radiologic imaging. In total, 101 patients with rare tumor entities or lesions and atypical manifestations of common tumors were enrolled retrospectively. Blinded readings were performed by four radiologists with varying levels of experience, who reported on: (a) correct diagnosis (CD), (b) time needed to find the diagnosis, and (c) diagnostic confidence, initially without followed by the assistance of the ORS. The experienced reader (3 years of experience post-residency, CD 49.5%), as well as the advanced reader with 1 year of experience post-residency (CD 43.6%), and a resident with 5 years of experience (CD 46.5%) made the correct diagnosis more frequently compared to the less experienced reader (CD 25.7%). A significant improvement in making the correct diagnosis was only achieved by the advanced reader, the resident with 5 years of experience (CD with ORS 58.4%; p < 0.001). The advanced reader with 1 year of experience post-residency improved slightly (CD ORS 47.5%). The experienced reader (CD ORS 50.5%) and the less experienced reader (CD ORS 27.7%) did not improve significantly. The overall subjective confidence increased significantly when ORS was used (3.2 ± 0.9 vs. 3.8 ± 0.9; p < 0.001). While the ORS had a positive impact on making the correct diagnosis throughout all readers, it favored radiologists with more clinical experience rather than inexperienced residents. Moreover, the ORS increased the diagnostic confidence of all radiologists significantly. In conclusion, the ORS had no significant impact on the diagnosis of rare or atypical abdominal tumors and lesions except for one reader. The greatest benefit is the increase in diagnostic confidence.

This paper provides imaging recommendations for pediatric abdominal tumors that arise outside of the solid viscera. These tumors are rare in children and have been categorized in two groups: abdominal wall and peritoneal tumors (desmoid tumor and desmoplastic small round cell tumor) and tumors that arise from the gastrointestinal tract (gastrointestinal stromal tumor and gastrointestinal neuroendocrine tumor). Authors offer consensus recommendations for imaging assessment of these tumors at diagnosis, during follow-up, and when off-therapy.

BACKGROUND: Gastrointestinal stromal tumors have been detected in 25% of the necropsies performed on NF1 patients, but have been reported only in 7% of NF1 patients in the largest series. Such data imply an important gap between the true presence of tumors and those diagnosed. Few genotype-phenotype relationships have been described but to date none referring to abdominal tumors.
OBJECTIVE: Evaluate retrospectively the efficacy of a regular and proactive follow-up of NF1 patients to early diagnose abdominal tumors and report their mutations.
METHODS: Cohort study performed between 2010 and 2020, with 43 NF1 adult patients followed at our Dermatology department.
RESULTS: Eight abdominal tumors were diagnosed in six patients, meaning that 14% of the followed patients developed an abdominal tumor. Five patients (83%) were asymptomatic. Five (83.3%) had a family history of NF1 with abdominal tumors (patients 1,2 and 3,4,5 were relatives).
CONCLUSIONS: Although currently gastrointestinal routine screening investigations for asymptomatic patients are not recommended in the guidelines, the family aggregation in our series suggests it should be considered a close follow-up of the relatives of a patient with an NF1-related abdominal tumor. Also, for the first time, two mutations [c.2041C > T (p.Arg681Ter) and c.4537C > T (p.Arg1513*)] have been associated with family aggregation of abdominal tumors in NF1 patients.

Positron emission tomography/computed tomography (PET/CT) with 18F-fluorodeoxyglucose (18F-FDG) is currently a standard imaging examination used in clinical practice, and plays an essential role in preoperative systemic evaluation and tumor staging in patients with tumors. However, 18F-FDG PET/CT has certain limitations in imaging of some tumors, like gastric mucus adenocarcinoma, highly differentiated hepatocellular carcinoma, renal cell carcinoma, and peritoneal metastasis. Therefore, to search for new tumor diagnosis methods has always been an important topic in radiographic imaging research. Fibroblast activation protein (FAP) is highly expressed in many epithelial carcinomas, and various isotope-labelled fibroblast activation protein inhibitors (FAPI) show lower uptake in the brain and abdominal tissues than in tumor, thus achieving high image contrast and good tumor delineation. In addition to primary tumors, FAPI PET/CT is better than FDG PET/CT for detecting lymph nodes and metastases. Additionally, the highly selective tumor uptake of FAPI may open up new application areas for the non-invasive characterization, staging of tumors, as well as monitoring tumor treatment efficacy. This review focuses on the recent research progress of FAPI PET/CT in the application to abdominal and pelvic tumors, with the aim of providing new insights for diagnostic strategies for tumor patients, especially those with metastases.

BACKGROUND: Benign cystic mesothelioma of the peritoneum is a rare, benign abdominal tumor. It can present with vague signs and symptoms and is often found on imaging or incidentally during surgery.
METHODS: We report the case of a 30-year-old man presenting with acute abdominal pain that radiated to the right iliac fossa. No masses were found on superficial or deep palpation or on conducting a sonography. The patient underwent a diagnostic laparoscopy with an appendectomy, which revealed a perforated appendix and two cysts in the pelvis and iliac fossa.
CONCLUSIONS: A benign cystic mesothelioma is an inclusion cyst found in the peritoneal cavity and has no specific clinical presentation. It can be symptomatic or found incidentally during surgery. Benign cystic mesotheliomas have a high recurrence rate and may undergo malignant transformation.
CONCLUSIONS: Complete surgical excision of benign cystic mesothelioma must always be the first step of the treatment plan for this condition. It is difficult to treat with no evidence-based treatment modality available; thus, treatment should only be undertaken in a specialized center.

UNASSIGNED: This study was conducted to compare continuous preperitoneal infusion (CPI) with continuous epidural infusion (CEI) of ropivacaine for pain relief and effect on pulmonary functions after major abdominal and pelvic surgeries.
UNASSIGNED: One hundred patients were randomized into two equal groups. Patients in CPI group (n = 50) received analgesia by continuous infusion of 0.2% ropivacaine, whereas those in the CEI group (n = 50) received continuous epidural infusion of 0.2% ropivacaine. The primary outcome was the first request of analgesia. The secondary outcome was the influence on the pulmonary functions.
UNASSIGNED: The time for the first request of analgesia was longer in the CPI group compared with that in the CEI group (7.3 ± 1.6 vs. 4.1 ± 1.1 h with P value = 0.001). The daily dose of morphine was lesser in CPI versus CEI group (11.3 ± 1 against 17.4 ± 0.9 mg). The pulmonary function tests were comparable except peak expiratory flow rate, which was better in CPI (170 ± 5.4) than CEI group (148.1 ± 5.8; with P value = 0.001).
UNASSIGNED: Continuous preperitoneal infusion provides a superior analgesic effect than the continuous epidural infusion as regards delayed first request of analgesia, better pain scores, lesser usage of additional analgesics with better respiratory function.

We present the case of a suprahepatic tumor related to mature cystic teratoma, extragonadal germ cell tumors are rare and represent from 1.6 to 5% of all germ cell tumors, the most common site and the extragonadal presentation is the mediastinum (50-70%), retroperitoneum (30-40%), other rare locations pineal gland, sacrococcal region, prostate and bladder; however, the supra-hepatic location is not so common and is not documented in the literature.
El tumor suprahepático se relaciona con el teratoma quístico maduro. Los tumores de células germinales extragonadales son raros y representan del 1,6 al 5% de todos los tumores de células germinales. El sitio más común y la presentación extragonadal es el mediastino (50-70%), seguido del retroperitoneo (30-40%) Otras localizaciones raras son la glándula pineal, la región sacrococcígea, la próstata y la vejiga; sin embargo, la localización suprahepática no es tan común y no está documentada en la literatura.

OBJECTIVE: To report our first results on sixteen patients affected by liver and abdominal malignant tumors, unfit for surgery or thermal ablation, treated with US-guided percutaneous irreversible electroporation (IRE).
METHODS: From June 2014 to December 2016, all patients meeting the inclusion criteria (malignant hepatic or abdominal tumors not eligible for resection or thermal ablation) and not meeting the exclusion criteria (heart arrhythmia, pro-hemorrhagic hematological alterations, tumor size > 8 cm, presence of a biliary metallic stent) referred to our institutions were prospectively enrolled to undergo percutaneous US-guided irreversible electroporation (IRE). Sixteen patients (age range 59-68 years, mean 63; 7 females) with 18 tumors (diameter range 1.3-7.5 cm) fulfilled the inclusion criteria and were included in the study. Data concerning efficacy (tested by a 1-week CEUS and a 4-week enhanced CT and/or enhanced MRI) and safety were recorded during a 18-month follow up.
RESULTS: All patients completed a 35-50-min procedure without complications. One patient with 6 cm Klatskin tumor also underwent a second session for 1 month. A 1-week CEUS and a 4-week e-CT and/or e-MRI arterial phase contrast enhancement analysis showed an overall reduction of arterial flow with confirmation of unenhanced lesions for seven nodules. After 1-18 months of follow up, no major complications were recorded and no tumor-related death occurred. The lesions of two patients disappeared 3 and 6 months after their treatment, respectively.
CONCLUSIONS: IRE is a promising ablation modality in the treatment of malignant hepatic and abdominal tumors unsuitable for resection or thermal ablation.

Pediatric retroperitoneal tumors in the renal bed are often large and heterogeneous, and their diagnosis based on conventional imaging alone is not possible. More advanced imaging methods, such as diffusion-weighted (DW) MRI and the use of intravoxel incoherent motion (IVIM), have the potential to provide additional biomarkers that could facilitate their noninvasive diagnosis.
To assess the use of an IVIM model for diagnosis of childhood malignant abdominal tumors and discrimination of benign from malignant lesions.
Retrospective.
Forty-two pediatric patients with abdominal lesions (n = 32 malignant, n = 10 benign), verified by histopathology.
1.5T MRI system and a DW-MRI sequence with six b-values (0, 50, 100, 150, 600, 1000 s/mm2 ).
Parameter maps of apparent diffusion coefficient (ADC), and IVIM maps of slow diffusion coefficient (D), fast diffusion coefficient (D*), and perfusion fraction (f) were computed using a segmented fitting model. Histograms were constructed for whole-tumor regions of each parameter.
Comparison of histogram parameters of and their diagnostic performance was determined using Kruskal-Wallis, Mann-Whitney U, and receiver-operating characteristic (ROC) analysis.
IVIM parameters D* and f were significantly higher in neuroblastoma compared to Wilms\' tumors (P < 0.05). The ROC analysis showed that the best diagnostic performance was achieved with D* 90th percentile (area under the curve [AUC] = 0.935; P = 0.002; cutoff value = 32,376 × 10-6 mm2 /s) and f mean values (AUC = 1.00; P < 0.001; cutoff value = 14.7) in discriminating between neuroblastoma (n = 11) and Wilms\' tumors (n = 8). Discrimination between tumor types was not possible with IVIM D or ADC parameters. Malignant tumors revealed significantly lower ADC, D, and higher D* values than in benign lesions (all P < 0.05).
IVIM perfusion parameters could distinguish between malignant childhood tumor types, providing potential imaging biomarkers for their diagnosis.
4 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;47:1475-1486.

OBJECTIVE: To compare the aspiration needle (AN) and core biopsy needle (PC) in endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) of abdominal masses.
METHODS: Consecutive patients referred for EUS-FNA were included in this prospective single-center trial. Each patient underwent a puncture of the lesion with both standard 22-gauge (G) AN (Echo Tip Ultra; Cook Medical, Bloomington, Indiana, United States) and the novel 22G PC (EchoTip ProCore; Cook Medical, Bloomington, Indiana, United States) in a randomized fashion; histology was attempted in the PC group only. The main study endpoint was the overall diagnostic accuracy, including the contribution of histology to the final diagnosis. Secondary outcome measures included material adequacy, number of needle passes, and complications.
RESULTS: Fifty six consecutive patients (29 men; mean age 68 years) with pancreatic lesions (n = 38), lymphadenopathy (n = 13), submucosal tumors (n = 4), or others lesions (n = 1) underwent EUS-FNA using both of the needles in a randomized order. AN and PC reached similar overall results for diagnostic accuracy (AN: 88.9 vs PC: 96.1, P = 0.25), specimen adequacy (AN: 96.4% vs PC: 91.1%, P = 0.38), mean number of passes (AN: 1.5 vs PC: 1.7, P = 0.14), mean cellularity score (AN: 1.7 vs PC: 1.1, P = 0.058), and complications (none). A diagnosis on the basis of histology was achieved in the PC group in 36 (64.3%) patients, and in 2 of those as the sole modality. In patients with available histology the mean cellularity score was higher for AN (AN: 1.7 vs PC: 1.0, P = 0.034); no other differences were of statistical significance.
CONCLUSIONS: Both needles achieved high overall diagnostic yields and similar performance characteristics for cytological diagnosis; histological analysis was only possible in 2/3 of cases with the new needle.