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Myxoinflammatory fibroblastic sarcoma (MIFS) is a rare soft tissue tumor with a predilection for the distal extremities and a tendency for local recurrence. Morphologically, MIFS consists of spindle and bizarre epithelioid cells resembling virocytes embedded in a fibrous to myxoid stroma with an abundant inflammatory infiltrate. Importantly, the molecular landscape of MIFS is wide and includes: VGLL3amplification, BRAFfusion/amplification and OGA/TGFBR3rearrangements. In this study, we describe a variant of MIFS showing a frequent nodular configuration associated with necrosis and recurrent YAP1::MAML2fusions. The cohort consisted of 7 patients (4 females and 3 males) ranging in age from 21 to 71 years (median: 47 years). Two tumors (28%) occurred in acral locations while the remaining cases were more widely distributed (thigh, n= 2; arm, n= 1; neck; n= 1; chest-wall, n= 1). Tumor size ranged from 10 to 38 mm (median: 20 mm). Histologically, lesions frequently presented as nodules with central areas of necrosis, and were predominantly composed of sheets of epithelioid cells with large vesicular nuclei and prominent nucleoli (Reed-Sternberg-like cells or virocytes). The stroma was mostly fibrous and showed a polymorphous inflammatory infiltrate. Myxoid stromal changes were focally seen in one case, and pseudolipoblasts were absent. The immunophenotype was nonspecific, with only pan-keratin (AE1-AE3) and cyclin D1 expression in a subset of cases. RNA-Sequencing detected YAP1::MAML2fusions in 3/7 cases; aCGH showed no significant gene copy number variations in 4 tested cases, and FISH analysis showed no VGLL3amplification in 1 tested case. Follow-up was available for 6 cases, ranging from 7 to 63 months (median: 42 months). Local recurrence and metastasis were not seen and one tumor showed spontaneous regression following initial biopsy. In conclusion, we describe a novel variant of MIFS with distinctive clinicopathological and molecular features for which we propose the term “nodular necrotizing” MIFS.

Supplemental Digital Content is available in the text.Elbow stiffness is a common reason for consultation. In recent years, arthroscopic techniques in elbow surgery have progressed, but there are still some contraindications to performance of arthroscopic synovectomy and release in this joint (elbows with anatomic deformity after multiple procedures, malunion, presence of osteosynthesis material, severe stiffness of >80 degrees, instability, or previous transposition of the ulnar nerve). Therefore, knowledge of a safe and reliable open approach to achieve elbow release and/or synovectomy is essential. We report the technical details of the modified lateral approach between extensor carpi radialis brevis and longus muscles, as well as the clinical results of 43 elbow release and/or synovectomy procedures, illustrating its feasibility. The modified lateral approach, providing visual control of the radial nerve and good anterior exposure of the elbow joint, is detailed. From 1994 to 2016, this approach was used in 43 release and/or synovectomy procedures of the elbow in 41 patients, 30 men and 11 women, with a mean age of 40.56 years (range, 17 to 84 y). Using this procedure, 38 elbows (93%) recovered full extension and 5 subtotal extension with an average deficit of 11 degrees (range, 5 to 20 degrees). All elbows were stable. No neurological complications were reported. The modified lateral approach preserves the insertion of the lateral epicondyle muscles that are major dynamic stabilizers and reduces the risk of instability. Initially described for the treatment of radial tunnel syndrome, it should also be recommended for elbow release and synovectomy.

Introduction : L’arthrodèse totale de poignet (ATP) a pour but d’obtenir un poignet indolore avec une poigne puissante. Son principal inconvénient est de sacrifier la mobilité et elle reste pour beaucoup d’auteurs une intervention de sauvetage. Cependant après une ou plusieurs interventions palliatives l’ATP donne de moins bons résultats. L’objectif de notre étude est d’évaluer à moyen-terme les résultats de l’ATP, et leur stabilité à long terme.