MR imaging of clear cell sarcoma (malignant melanoma of the soft parts): A multicenter correlative MRI-pathology study of 21 cases and literature review

Objective. To evaluate MR imaging and pathology findings in order to define the characteristic features of clear cell sarcoma of the soft tissues (malignant melanoma of the soft parts). Design and patients. MR examinations of 21 patients with histologically proven clear cell sarcoma of the musculoskeletal system were retrospectively reviewed and assessed for shape, homogeneity, delineation, signal intensities on T1- and T2-weighted images, contrast enhancement, relationship with adjacent fascia or tendon, secondary bone involvement, and intratumoral necrosis. In 19 cases the pathology findings were available for review and for a comparative MR-pathology study. Results. On T1-weighted images, lesions were isointense (n=3), hypointense (n=7) or slightly hyperintense to muscle (n=11). Immunohistochemical examination was performed in 17 patients. All 17 specimens showed positivity for HMB-45 antibody. In nine of 11 lesions with slightly increased signal intensity on T1-weighted images, a correlative MR imaging-pathology study was possible. All nine were positive to HMB-45 antibody. Conclusions. Clear cell sarcoma of the musculoskeletal system often has a benign-looking appearance on MR images. In up to 52% of patients, this lesion with melanocytic differentiation has slightly increased signal intensity on T1-weighted images compared with muscle. As the presence of this relative higher signal intensity on T1-weighted images is rather specific for tumors displaying melanocytic differentiation, radiologists should familiarize themselves with this rare entity and include it in their differential diagnosis when confronted with a well- defined, homogeneous, strongly enhancing mass with slightly higher signal intensity compared with muscle on native T1-weighted images

A study of the mechanochemical synthesis of NaNbO3

International audienceWe have studied the mechanochemical synthesis of NaNbO3, prepared from a powder mixture of Na2CO3 and Nb2O5. The formation of NaNbO3 during milling was followed using thermal analysis and X-ray diffraction. According to the thermogravimetric analysis, after 20 and 40 h of milling there was still some residual carbonate, while the X-ray diffraction shows NaNbO3 as the major crystalline phase present in the mixture. Based on the quantitative XRD phase analysis, the residual reactants were amorphous and as such undetectable with the X-ray diffraction. Furthermore, an X-ray line-broadening analysis was used to determine the NaNbO3 crystallite size and the microstrain. A decrease in the NaNbO3 crystallite size coupled with an increase in the amount of microstrains was found from 10 to 40 h of mechanochemical treatment. Finally, the TEM analysis confirmed the NaNbO3 crystallite size determined by the X-ray line-broadening analysis

Breast asymmetry, distortion and density are key factors for false positive decisions

Aim: Understanding both normal mammographic appearance and how false positive (FP) errors occur is paramount to improving the efficiency and diagnostic accuracy of screening mammography services. While much of the focus of research is on increasing knowledge about the appearances and imaging of breast cancers, this study reports on findings where breast screen readers are asked to comment on past incorrect decisions by assigning a lexicon that best describes a known FP region. Method: Fifteen breast screen readers were given two tasks. The first was to assess nine normal screening cases which had attracted a high number of FP decisions in a test set of 60 cases in a previous study with 129 readers. In the second task, the 15 readers in this study, who were made aware that the nine cases were normal, were directed to view distinct regions of interest (ROI) that represented the FP markings from past readings in the blinded observer performance study. A list of descriptors derived from literature was used to assist readers to describe the mammographic appearance within those ROIs. Results: In the first task, readers identified breast density as the greatest difficulty in determining normality. In the second task, asymmetry of breast tissue and a suspicion of architectural distortion (AD) were the top two reasons our readers gave to explain the high number of past FP decisions. Additionally, our readers believed past FP decisions were less likely to reflect a suspicion of breast lesions or masses (second task). Conclusion: The classification of normal cases remains a challenging task, influenced by asymmetry and breast density. FP decisions may reflect a suspicion of AD and appear less related to suspicion of masses

Sudden Death of a Young Adult Associated with Bacillus cereus Food Poisoning▿

A lethal intoxication case, which occurred in Brussels, Belgium, is described. A 20-year-old man died following the ingestion of pasta contaminated with Bacillus cereus. Emetic strains of B. cereus were isolated, and high levels of cereulide (14.8 μg/g) were found in the spaghetti meal