Department of Pathology and Laboratory Medicine, Cumming School of Medicine, Calgary, Alberta, Canada.
Department of Genetics, Cumming School of Medicine, Calgary, Alberta, Canada.
Pediatr Dev Pathol. 2021 Jan-Feb;24(1):62-67. doi: 10.1177/1093526620968807. Epub 2020 Oct 26.
Gardner fibroma (GF) is a benign soft-tissue tumor that is associated with Gardner syndrome and can progress to, or co-occur with, desmoid fibromatosis (DF). Herein, we report a unique case of an 11-year-old boy who presented with a rapidly growing soft-tissue mass after biopsy of a stable fat-rich lesion present in the calf muscles since infancy, with Magnetic resonance imaging findings suggesting an intramuscular adipocytic tumor. The resection showed GF and DF. DF arising from a preexisting GF (the so-called "GF-DF sequence") is a well-documented phenomenon. Although immunohistochemistry was negative for nuclear β-catenin expression, a S45F mutation, which has been associated with aggressive behavior in DF, was identified in both components using a next-generation sequencing-based molecular assay. This is the first time a mutation in has been identified in GF and the GF-DF sequence, thus expanding our knowledge of the molecular pathogenesis of the GF-DF sequence and highlighting the role of molecular testing in pediatric soft-tissue tumors. The histologic findings of an adipocyte-rich intramuscular GF also are unique, expanding the morphological spectrum of GF and adding GF to the differential diagnosis of intramuscular lesions with an adipocytic component.
Gardner 纤维瘤（GF）是一种良性软组织肿瘤，与 Gardner 综合征相关，并可进展为或与硬纤维瘤病（DF）同时发生。在此，我们报告了 1 例 11 岁男孩的独特病例，该男孩在小腿肌肉中存在稳定的富含脂肪的病变，出生后进行活检后出现快速生长的软组织肿块，磁共振成像结果提示为肌内脂肪细胞肿瘤。切除后显示 GF 和 DF。从先前存在的 GF 中出现的 DF（所谓的“GF-DF 序列”）是一种有充分文献记录的现象。尽管免疫组化显示核 β-连环蛋白表达阴性，但使用基于下一代测序的分子检测在两个成分中均发现了与 DF 侵袭性行为相关的 S45F 突变。这是首次在 GF 和 GF-DF 序列中发现突变，从而扩展了我们对 GF-DF 序列分子发病机制的认识，并强调了分子检测在儿科软组织肿瘤中的作用。富含脂肪细胞的肌内 GF 的组织学发现也很独特，扩展了 GF 的形态谱，并将 GF 添加到具有脂肪细胞成分的肌内病变的鉴别诊断中。
