Periurethral mass mimicking neoplasm after injection of macroplastique for postprostatectomy stress incontinence: A pitfall on 18F-FDG PET/CT

International audienceA 64-year-old man underwent initial 18F-FDG PET/CT staging for gastric cardia adenocarcinoma, which showed the primary gastric tumor, several bone metastases, and high uptake in a periurethral mass mimicking pelvic neoplasm developed after injection of polydimethylsiloxane (Macroplastique) urethral bulking agent 6 years ago for postprostatectomy stress urinary incontinence. This case showed a very rare complication of silicon particle injection therapy, and the intense uptake is likely due to granulomatous reaction around the implant

18F-FDG PET/CT in anti-NMDA receptor encephalitis: Typical pattern and follow-up

International audienceWe report the case of a 28-year-old woman presenting behavior disorders of subacute onset. She was referred in our institution for a suspicion of limbic encephalitis. 18F-FDG PET/CT did not show any mesiotemporal abnormality but depicted a decreased uptake of bilateral parietal and occipital lobes. This atypical pattern was compatible with an anti-N-methyl-D-aspartate receptor encephalitis that was later confirmed

Assessment of the Association between Entropy in PET/CT and Response to Anti-PD-1/PD-L1 Monotherapy in Stage III or IV NSCLC

Anti-PD-1/PD-L1 therapy indications are broadened in non-small cell lung cancer (NSCLC) although immune checkpoint inhibitors (ICI) do not provide benefits for the entire population. Texture features based on positron emission tomography/computed tomography (PET/CT), especially entropy (based on a gray-level co-occurrence matrix (GLCM)), could be interesting as predictors in NSCLC. The aim of our retrospective study was to evaluate the association between GLCM-entropy and response to anti-PD-1/PD-L1 monotherapy at the first evaluation in stage III or IV NSCLC, comparing patients with progressive disease (PD) and non-progressive disease (non-PD). In total, 47 patients were included. Response Evaluation Criteria in Solid Tumors (RECIST 1.1) were used to evaluate the response to ICI treatment (nivolumab, pembrolizumab, or atezolizumab). At the first evaluation, 25 patients were PD and 22 were non-PD. GLCM-entropy was not predictive of response at the first evaluation. Furthermore, GLCM-entropy was not associated with progression-free survival (PFS) (p = 0.393) or overall survival (OS) (p = 0.220). Finally, GLCM-entropy measured in PET/CT performed before ICI initiation in stage III or IV NSCLC was not predictive of response at the first evaluation. However, this study demonstrates the feasibility of using texture parameters in routine clinical practice. The interest of measuring PET/CT texture parameters in NSCLC remains to be evaluated in larger prospective studies

Textural analysis in FDG PET of locally advanced non-small cell lung cancer: Prognostic value of entropy

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