Pediatric neoplasms with a myofibroblastic differentiation are frequent in children, in particular myofibroma. Recently, a novel deep soft tissue myofibroblastic neoplasm has been described with high cellularity, a smooth muscle phenotype and SRF-RELA fusion. We report the case of a 15-year-old boy who presented with a tumor of the deep soft tissue of the arm, with overlapping histological features with the recently described SRF-RELA group of myofibromas but differing by the presence of calcifications, a novel SRF-STAT6 fusion transcript and nuclear expression of STAT6. No local recurrence nor distant metastasis was detected at the current follow-up of 29 months. The clinical relevance of this novel fusion requires further investigations.

小儿具有成肌纤维母细胞分化的小儿肿瘤特别是肌纤维瘤。近来，已经描述了具有高细胞性，平滑肌表型和SRF-RELA融合的新型深层软组织肌成纤维细胞瘤。我们报道了一个15岁男孩的病例，该男孩表现出手臂深部软组织肿瘤，具有与最近描述的肌纤维瘤SRF-RELA组重叠的组织学特征，但因钙化的存在而不同，这是一种新型SRF-STAT6融合转录本和STAT6的核表达。目前29个月的随访中未发现局部复发或远处转移。这种新型融合的临床意义需要进一步研究。