Papke David J, Oliveira Andre M, Chou Margaret M, Fletcher Christopher D M
Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, MA, 02115, USA.
Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA.
Virchows Arch. 2021 Nov;479(5):1007-1012. doi: 10.1007/s00428-021-03149-8. Epub 2021 Jul 2.
Nodular fasciitis is a benign myofibroblastic neoplasm that characteristically enlarges rapidly and then usually regresses spontaneously. While the vast majority of tumors are benign, there are rare reports of morphologically benign nodular fasciitis giving rise to metastases, not predictable on histologic grounds. Here, we report what we believe is an example of morphologically malignant nodular fasciitis, which occurred in the upper extremity of a 7-year-old male. The tumor was composed of short, intersecting fascicles of myofibroblastic cells in a loose myxoid matrix, with keloidal hyalinization and admixed osteoclastic giant cells, all characteristic of nodular fasciitis. However, it additionally exhibited striking nuclear pleomorphism, a feature not compatible with conventional nodular fasciitis. Fluorescence in situ hybridization demonstrated a USP6 translocation, confirmed by next-generation sequencing to be the novel CALD1-USP6 fusion. No other somatic or germline mutations were detected. This case adds to the expanding morphologic and molecular genetic spectrum of nodular fasciitis.
结节性筋膜炎是一种良性肌成纤维细胞肿瘤，其特征是迅速增大，然后通常会自发消退。虽然绝大多数肿瘤是良性的，但有罕见报道称形态学上良性的结节性筋膜炎会发生转移，这在组织学上无法预测。在此，我们报告一例我们认为是形态学上恶性的结节性筋膜炎病例，发生于一名7岁男性的上肢。肿瘤由短的、相互交叉的肌成纤维细胞束组成，位于疏松的黏液样基质中，伴有瘢痕疙瘩样玻璃样变和散在的破骨细胞样巨细胞，这些都是结节性筋膜炎的特征。然而，它还表现出显著的核多形性，这一特征与传统的结节性筋膜炎不符。荧光原位杂交显示有USP6易位，经二代测序证实为新的CALD1-USP6融合。未检测到其他体细胞或胚系突变。该病例增加了结节性筋膜炎不断扩大的形态学和分子遗传学谱。
