Expression of the SS18/SYT-SSX fusion protein is believed to underlie the pathogenesis of synovial sarcoma (SS). Recent evidence suggests that deregulation of the Wnt pathway may play an important role in SS but the mechanisms whereby SS18-SSX might affect Wnt signaling remain to be elucidated. Here, we show that SS18/SSX tightly regulates the elevated expression of the key Wnt target AXIN2 in primary SS. SS18-SSX is shown to interact with TCF/LEF, TLE and HDAC but not β-catenin in vivo and to induce Wnt target gene expression by forming a complex containing promoter-bound TCF/LEF and HDAC but lacking β-catenin. Our observations provide a tumor-specific mechanistic basis for Wnt target gene induction in SS that can occur in the absence of Wnt ligand stimulation.

Background: Infectious endocarditis is a life-threatening disease, requiring prompt and accurate diagnosis. The aim of this article is to perform a systematic review and meta-analysis of the literature to estimate the performance of fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) for the diagnosis of native valve endocarditis (NVE). Methods: Selected articles evaluating the diagnostic accuracy of 18F-FDG PET/CT in patients with suspected NVE, resulting from a comprehensive literature search through the PubMed/MEDLINE and Cochrane library databases until April 2020, were included for the systematic review and meta-analysis. Results: Seven studies (351 episodes of suspected NVE) were included. 18F-FDG PET/CT yielded a pooled sensitivity of 36.3% and a pooled specificity of 99.1% for the diagnosis of NVE. The pooled positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio were 8.3, 0.6, and 15.3, respectively. The sensitivity increased using contemporary PET/CT device with state-of-the-art patient preparation as well as innovative image acquisitions or adding the results of 18F-FDG PET/CT in a multimodality strategy. Conclusions: In our systematic review and meta-analysis, 18F-FDG PET/CT yielded a poor pooled sensitivity with an otherwise excellent pooled specificity for the diagnosis of NVE; however, several factors may increase the sensitivity without affecting the specificity and these factors should be better evaluated in future studies.

We report the case of a 45-year-old woman who palpated a voluminous painless lump in the superior outer quadrant of her left breast. Her past medical history revealed an acute myeloid leukemia (AML) treated and considered in remission 1 month prior to this discovery. Imaging work-up by mammogram, US, and MRI showed multiples masses suspect of malignancy in both breasts. US-guided needle biopsy was performed in the palpable mass and in one of the multiple lesions located in the right breast. Histologic findings were compatible with a granulocytic sarcoma in both breasts, which was considered as a relapse of the AML treated a few months earlier.

The foot and the ankle are small structures commonly affected by disorders, and their complex anatomy represents a significant diagnostic challenge. By providing information on anatomic and bone structure that cannot be obtained from functional imaging, SPECT/CT image fusion can be particularly useful in increasing diagnostic certainty about bone pathology. However, because of the lengthy duration of a SPECT acquisition, a patient's involuntary movements may lead to misalignment between SPECT and CT images. Patient motion can be reduced using a dedicated patient support. We designed an ankle-and foot-immobilizing device and measured its efficacy at improving image fusion. Methods: We enrolled 20 patients who underwent SPECT/CT of the ankle and foot with and without a foot support. The misalignment between SPECT and CT images was computed by manually measuring 14 fiducial markers chosen among anatomic landmarks also visible on bone scintigraphy. ANOVA was performed for statistical analysis. Results: The absolute average difference without and with support was 5.1 ± 5.2 mm (mean ± SD) and 3.1 ± 2.7 mm, respectively, which is significant (P , 0.001). Conclusion: The introduction of the foot support significantly decreased misalignment between SPECT and CT images, which may have a positive clinical influence in the precise localization of foot and ankle pathology.Key Words: SPECT/CT; misalignment; lower limb; patient motion Nucl Med Technol 2015; 43:98-102 DOI: 10.2967/jnmt.114.145771 SPECT/ CT is an imaging technique combining both functional and anatomic information (1-5) in the identification and characterization of different disorders (2), including endocrine and neuroendocrine diseases, infection and inflammation (2,4,(6)(7)(8), and benign and malignant bone diseases (2,4). SPECT/CT is currently a main, growing focus of interest in the assessment of musculoskeletal disorders (5). JThe high sensitivity provided by SPECT combined with the increased specificity provided by CT (7,9) can increase accuracy and confidence in areas of special diagnostic difficulty, such as the foot and the ankle (7,9,10). Indeed, in clinical examination, it can be challenging to find the origin of the pain (10) even for the most experienced of clinicians (4), mainly because of the variety of etiologies producing similar patient complaints and clinical abnormalities (8). The foot and the ankle comprise a complex anatomy of small structures (1,9,10), including bones, ligaments, and tendons (11), which can be subject to inflammatory and degenerative diseases producing severe disability (12).To make specific diagnoses and deliver appropriate treatments, small or focal pathologic changes must be well localized (7). Currently, MR imaging is the most widely used technique in evaluating chronic foot and ankle pain, although SPECT/CT can play an important role in assessing the origin of pain (4,10) and early stages of disease (13). On the other hand, in early degenerative changes in the varus and valgus misaligned hind foot, SPECT/CT is use...

We report the case of a 45-year-old woman with a history of right breast reconstruction with silicone implant for breast cancer. An 18F-FDG PET/CT performed several years later revealed the presence of 18F-FDG–avid nodules at the periphery of the silicone implant, in the right internal mammary chain, and in the contralateral breast. Needle core biopsies were positive for bilateral silicone granulomas, without any sign of malignancy. This case displays intense 18F-FDG uptake in silicone granulomas affecting the contralateral breast after implant reconstruction.