Xanthogranulomatous cholecystitis mimicking gallbladder carcinoma with a false-positive result on fluorodeoxyglucose PET

Recently, several reports have demonstrated that fluorine-18 fluorodeoxyglucose positron emission tomography （FDG-PET） is useful in differentiating between benign and malignant lesions in the gallbladder. However, there is a limitation in the ability of FDG-PET to differentiate between inflammatory and malignant lesions. We herein present a case of xanthogranulomatous cholecystitis misdiagnosed as gallbladder carcinoma by ultrasonography and computed tomography. FDG-PET also showed increased activity. In this case, FDG-PET findings resulted in a false-positive for the diagnosis of gallbladder carcinoma.

Prognostic value and clinical correlations of18-fluorodeoxyglucose metabolism quantifiers in gastriccancer

AIM： To investigate the correlations of pre-treatmentpositron emission tomography-computer tomography（PET-CT） metabolic quantifiers with clinical data ofunstratified gastric cancer （GC） patients.METHODS： Forty PET-CT scans utilising 18-fluorodeoxyglucosein patients who received no prior treatmentwere analysed. Analysis involved measurements ofmaximum and mean standardised uptake volumes（SUV）, coefficient of variation （COV）, metabolictumour volumes and total lesion glycolysis of differentthresholds above which the tumor volumes wereidentified. The threshold values were： SUV absolutevalue of 2.5, 30% of SUVmax, 40% of SUVmax,and liver uptake-based （marked 2.5, 30, 40 and liv,respectively）. Clinical variables such as age, sex,clinical stage, performance index, weight loss, tumorhistological type and grade, and CEA and CA19.9 levelswere included in survival analysis. Patients receivedvarious treatment modalities appropriate to theirdisease stage and the outcome was defined by time tometastasis （TTM） and overall survival （OS）. Clinical andmetabolic parameters were evaluated by analysis of variance, receiver operating characteristics, univariateKaplan-Meier, and multivariate Cox models. P 〈 0.05was considered statistically significant.RESULTS： Significant differences were observedbetween initially disseminated and non-disseminatedpatients in mean SUV （6.05 vs 4.13, P = 0.008）, TLG2.5（802 cm3 vs 226 cm3; P = 0.031）, and TLG30 （436 cm3vs 247 cm3, P = 0.018）. Higher COV was associatedwith poor tumour differentiation （0.47 for G3 vs0.28 for G1 and G2; P = 0.03）. MTV2.5 was positivelycorrelated to patient weight loss （〈 5%, 5%-10%and 〉 10%： 40.4 cm3 vs 123.6 cm3 vs 181.8 cm3,respectively, P = 0.003）. In multivariate Cox analysis,TLG30 was prognostic for OS （HR = 1.001, 95%CI：1.0009-1.0017; P = 0.047） for the whole group ofpatients. In the same model yet only including patientswithout initial disease dissemination TLG30 （HR = 1.009,95%CI： 1.003-1.014; P = 0.004） and MTV2.5 （HR = 1.02,95%CI： 1.002-1.036; P = 0.025） were prognostic forOS; for TTM TLG30 was the only significant prognosticvariable （HR = 1.006, 95%CI： 1.001-1.012; P = 0.02）.CONCLUSION： PET-CT in GC may represent a valuablediagnostic and prognostic tool that requires furtherevaluation in highly standardised environments such asrandomised clinical trials.