- Histopathology（Malik、Orr、Chami 等，St. Jude 儿童研究医院等）：汇集迄今最大的 10 例儿童 PLAG1 重排纤维黏液样肿瘤（P-FMT），患儿 3 个月至 10 岁（中位 4 岁），发生于四肢、躯干、颈部。
- 形态与免疫：边界清楚，温和成纤维细胞样梭形细胞位于胶原至黏液样间质，仅 2 例局灶见成熟脂肪；CD34、desmin 全部阳性。
- 分子：FISH/测序证实 PLAG1 重排，伙伴为 COL1A2（3）、MEG3（2）、BOC、YWHAZ、EEF1A1、CHCHD7（各 1）；DNA 甲基化谱全部与脂肪母细胞瘤聚类，与其他间叶肿瘤分开；二者均有 8 号染色体获得。随访中位 22 个月，均无复发。
- 诊断意义：儿童脂肪很少或无脂肪的纤维黏液样梭形细胞肿瘤、CD34/desmin 阳性时，应想到 PLAG1 检测；作者主张将其视为脂肪母细胞瘤的成纤维细胞型/少脂肪亚型，而非独立实体。本站仅获摘要。
收录范围：PubMed 结构式摘要中英对照。原文为 Wiley 开放获取，但出版社页面被 Cloudflare 拦截、Unpaywall 当日尚未收录，本站未获全文与图表。
摘要
目的：儿童 PLAG1 重排纤维黏液样肿瘤（P-FMT）是一种新近认识的软组织肿瘤，特征为以纤维黏液样形态为主、脂肪细胞分化极少或缺如，且恒定表达 CD34 和 desmin。P-FMT 究竟是独立实体还是脂肪母细胞瘤的形态学变异型，目前尚有争议。本研究旨在进一步明确 P-FMT 的特征，并评估其与脂肪母细胞瘤的关系。
方法与结果：我们汇集了迄今最大的 P-FMT 队列（n = 10），进行全面的临床病理、分子及表观遗传学分析。队列男女各 5 例，年龄 3 个月至 10 岁（中位 4 岁），肿瘤发生于四肢、躯干和颈部。组织学上，所有病变边界清楚，由温和的成纤维细胞样梭形细胞构成，间质胶原性至黏液样；2 例局灶含成熟脂肪细胞。所有肿瘤均表达 CD34 和 desmin。经荧光原位杂交或分子测序证实存在 PLAG1 重排，融合伙伴为 COL1A2（n = 3）、MEG3（n = 2）、BOC（n = 1）、YWHAZ（n = 1）、EEF1A1（n = 1）和 CHCHD7（n = 1）。DNA 甲基化谱分析显示，在层次聚类与降维分析中，所有 P-FMT 均与脂肪母细胞瘤聚为一组，而与其他间叶性肿瘤分离。拷贝数谱显示 P-FMT 与脂肪母细胞瘤均有具统计学意义的 8 号染色体获得。所有有随访资料的病例（中位随访 22 个月）均呈良性经过，无复发。
结论：P-FMT 在形态上类似成纤维细胞型脂肪母细胞瘤，并与经典脂肪母细胞瘤有多方面相似之处，包括免疫表型相同、PLAG1 重排且融合伙伴重叠、表观遗传学特征一致以及一致的良性生物学行为。这些发现支持将 P-FMT 归为脂肪母细胞瘤谱系中的成纤维细胞型或少脂肪细胞亚型，而非独立实体。
- Histopathology (Malik, Orr, Chami and colleagues; St. Jude and others): the largest series to date of 10 PLAG1-rearranged paediatric fibromyxoid tumours (P-FMT), aged 3 months to 10 years (median 4), in extremities, trunk and neck.
- Morphology and IHC: well-demarcated bland fibroblastic spindle cells in collagenous to myxoid stroma, with mature fat focally in only 2; CD34 and desmin positive in all.
- Molecular: PLAG1 rearrangement confirmed by FISH or sequencing with partners COL1A2 (3), MEG3 (2), BOC, YWHAZ, EEF1A1 and CHCHD7 (1 each); all clustered with lipoblastoma on DNA methylation, apart from other mesenchymal tumours; both share chromosome 8 gain. No recurrence at median 22 months.
- Diagnostic point: a CD34/desmin-positive fibromyxoid spindle cell tumour with little or no fat in a child should prompt PLAG1 testing; the authors place P-FMT within the lipoblastoma spectrum rather than as a separate entity. Abstract only.
Scope: the structured PubMed abstract. The article is Wiley open access, but the publisher page was blocked by Cloudflare for our fetcher and Unpaywall had not yet indexed it, so full text and figures were not obtained.
Abstract
Aims: Paediatric PLAG1-rearranged fibromyxoid tumour (P-FMT) is an emerging soft-tissue neoplasm characterized by predominantly fibromyxoid morphology, minimal to absent adipocytic differentiation and consistent CD34 and desmin positivity. It is debated whether P-FMT represents a distinct entity or a morphological variant of lipoblastoma. We aim to better characterize P-FMT and assess its relationship with lipoblastoma.
Methods and results: We assembled the largest cohort of P-FMT (n = 10) and performed comprehensive clinicopathological, molecular and epigenetic characterization. The cohort comprised five males and five females, aged 3 months to 10 years (median 4 years), with tumours arising in the extremities, trunk and neck. Histologically, all were well-demarcated lesions with bland fibroblastic spindle cells in collagenous to myxoid stroma; two cases focally contained mature adipocytes. All tumours expressed CD34 and desmin. PLAG1 rearrangements were confirmed by fluorescence in situ hybridization or molecular sequencing, with fusion partners identified as COL1A2 (n = 3), MEG3 (n = 2), BOC (n = 1), YWHAZ (n = 1), EEF1A1 (n = 1) and CHCHD7 (n = 1). DNA methylation profiling demonstrated that all P-FMTs grouped with lipoblastoma on hierarchical clustering and dimensionality reduction analysis and segregated from other mesenchymal tumours. Copy number profiles showed statistically significant chromosome 8 gain in both P-FMT and lipoblastoma. All cases with follow-up (median 22 months) demonstrated benign behaviour without recurrence.
Conclusions: Our findings of morphological resemblance to fibroblastic lipoblastoma and multiple similarities to classic lipoblastoma, including identical immunophenotype, PLAG1 rearrangements with overlapping partners, common epigenetic signature and uniformly benign behaviour, support classification of P-FMT as a fibroblastic or minimally adipocytic subtype within the lipoblastoma spectrum, rather than a distinct entity.