Gandhi Jatin S, Deeb Kristin K, Chen Eleanor Y, Bandhlish Anshu
Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA, USA.
Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, USA.
Int J Surg Pathol. 2025 Aug;33(5):1190-1195. doi: 10.1177/10668969241300492. Epub 2025 Jan 7.
Hemosiderotic fibrolipomatous tumor (HFLT) and myxoinflammatory fibroblastic sarcoma (MIFS) are rare, locally aggressive soft tissue tumors with a predilection for distal extremities of middle-aged adults. Hybrid tumors (HFLT-MIFS) demonstrate overlapping features of both and share recurrent translocation (1;10) (p22; q24). We describe a tumor with high-grade sarcomatous transformation of a hybrid HFLT-MIFS, with a novel gene fusion, presenting as a right foot soft tissue mass in an 85-year-old woman. Histologically, the tumor showed a high-grade sarcoma with areas of hybrid HFLT-MIFS in subsequent resection. The patient was treated surgically with a below-knee amputation and interval radiation therapy. On RNA-based next-generation sequencing, the tumor harbored a novel gene fusion. In addition to reporting a novel gene fusion in a rare example of hybrid HFLT-MIFS with high-grade sarcomatous transformation, we also discuss relevant morphological features of sarcomatous HFLT and provide a brief review of reported neoplasms with gene fusions.
含铁血黄素沉着性纤维脂肪瘤样肿瘤（HFLT）和黏液炎性成纤维细胞肉瘤（MIFS）是罕见的、具有局部侵袭性的软组织肿瘤，好发于中年成年人的四肢远端。混合性肿瘤（HFLT-MIFS）表现出两者的重叠特征，并具有复发性易位（1；10）（p22；q24）。我们描述了一例具有高级别肉瘤转化的混合性HFLT-MIFS肿瘤，伴有一种新的基因融合，表现为一名85岁女性右足的软组织肿块。组织学上，肿瘤在后续切除中显示为高级别肉瘤伴混合性HFLT-MIFS区域。患者接受了膝下截肢手术及间隔放疗。基于RNA的二代测序显示，该肿瘤存在一种新的基因融合。除了报道在一例罕见的具有高级别肉瘤转化的混合性HFLT-MIFS中发现新的基因融合外，我们还讨论了肉瘤样HFLT的相关形态学特征，并简要回顾了报道的具有基因融合的肿瘤。
