Department of Pathology and Laboratory Medicine, Pennsylvania Hospital of the University of Pennsylvania Health System.
Department of Pathology and Laboratory Medicine, Hospital of the University of Pennsylvania.
Am J Surg Pathol. 2020 Nov;44(11):1535-1540. doi: 10.1097/PAS.0000000000001548.
Primary pulmonary myxoid sarcoma (PPMS) is a recently reported, exceedingly rare low-grade lung neoplasm characterized by reticular/lace-like growth of spindle to epithelioid cells embedded in an abundant myxoid matrix. Morphologically, it overlaps with a myxoid variant of angiomatoid fibrous histiocytoma (AFH) of the soft tissue. Genetically, they were both reported to harbor EWSR1-CREB1 fusion, while EWSR1-ATF1 has only been reported in AFH thus far. We report a case of primary pulmonary low-grade myxoid spindle cell tumor with morphologic and immunohistochemical features of PPMS but with an EWSR1-ATF1 fusion gene. In addition, we also encountered a case of endobronchial AFH with EWSR1-CREB1 translocation but also focal morphologic features of PPMS. These findings provide new evidence supporting the concept that PPMS and a myxoid variant of AFH represent a continuum with overlapping histologic, immunohistochemical, and genetic features.
原发性肺黏液样肉瘤（PPMS）是一种新近报道的、极为罕见的低度肺肿瘤，其特征为梭形至上皮样细胞呈网状/花边状生长，嵌入丰富的黏液样基质中。在形态学上，它与软组织中的血管外皮细胞瘤样纤维组织细胞瘤（AFH）的黏液样变体重叠。在遗传学上，它们都被报道存在 EWSR1-CREB1 融合，而 EWSR1-ATF1 迄今仅在 AFH 中报道过。我们报告了一例原发性肺低度黏液性梭形细胞肿瘤，其形态学和免疫组织化学特征与 PPMS 相似，但存在 EWSR1-ATF1 融合基因。此外，我们还遇到了一例支气管内 AFH，存在 EWSR1-CREB1 易位，但也存在 PPMS 的局灶形态特征。这些发现为 PPMS 和 AFH 的黏液样变体代表具有重叠的组织学、免疫组织化学和遗传学特征的连续体的概念提供了新的证据。
