Diagnostic Utility of PRAME in Rare Melanoma Mimics: A Comparative Analysis Including GNET, MMNST, Epithelioid MPNST, and MITF-Rearranged Melanocytic Tumors.

IF 1.1 4区 医学 Q3 DERMATOLOGY
Ahmed Shah, Jeremiah F Molligan, Carina A Dehner, Jorge Torres-Mora
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引用次数: 0

Abstract

Background: Differentiating metastatic melanoma from histologic mimics such as malignant gastrointestinal neuroectodermal tumor (GNET), malignant melanotic nerve sheath tumor (MMNST), and epithelioid malignant peripheral nerve sheath tumor (EMPNST) poses significant diagnostic challenges due to overlapping morphology and immunophenotypes. PRAME is a novel immunohistochemical marker increasingly used to distinguish melanoma from its mimics, but remains underexplored in these rare tumor types.

Methods: PRAME immunohistochemistry was performed on four GNETs, seven MMNSTs, 10 EMPNSTs, 16 metastatic melanomas (including eight undifferentiated melanomas), and two MITF-rearranged melanocytic tumors. PRAME expression was scored from 0 to 4+ based on the percentage of tumor nuclei showing moderate to strong staining.

Results: All GNETs, MMNSTs, and MITF-rearranged tumors were PRAME-negative. EMPNSTs showed variable expression: six were negative (0-1), one equivocal (2+), and three positive (3-4+). Fifteen of 16 melanomas were PRAME-positive. PRAME scores differed significantly among tumor types (p = 1.99 × 10-5). PRAME demonstrated high sensitivity and specificity for distinguishing metastatic melanoma from primary mimickers including GNET and MMNST, but low specificity in EMPNST (71.4%).

Conclusions: PRAME reliably distinguishes metastatic melanoma from GNET and MMNST, supporting its use in this differential. However, its reduced specificity in EMPNST limits its standalone diagnostic value in this context, emphasizing the need for a multimodal approach.

PRAME在罕见黑色素瘤模拟物中的诊断应用:包括GNET、MMNST、上皮样MPNST和mitf重排黑色素细胞肿瘤的比较分析。
背景:由于形态学和免疫表型的重叠,转移性黑色素瘤与恶性胃肠道神经外胚层肿瘤(GNET)、恶性黑素性神经鞘肿瘤(MMNST)和上皮样恶性周围神经鞘肿瘤(EMPNST)的鉴别具有重大的诊断挑战。PRAME是一种新的免疫组织化学标记物,越来越多地用于区分黑色素瘤和类似物,但在这些罕见的肿瘤类型中仍未得到充分的研究。方法:对4例GNETs、7例MMNSTs、10例EMPNSTs、16例转移性黑色素瘤(包括8例未分化黑色素瘤)和2例mitf重排黑色素细胞瘤进行PRAME免疫组化。根据中度至强烈染色的肿瘤核的百分比,PRAME的表达从0到4+评分。结果:所有GNETs、MMNSTs和mitf重排肿瘤均为prame阴性。EMPNSTs表现为不同的表达:阴性6例(0-1),模棱两可1例(2+),阳性3例(3-4+)。16例黑色素瘤中有15例prame阳性。不同肿瘤类型间PRAME评分差异有统计学意义(p = 1.99 × 10-5)。PRAME在区分转移性黑色素瘤与原发性模拟物(包括GNET和MMNST)方面具有很高的敏感性和特异性,但在EMPNST方面的特异性较低(71.4%)。结论:PRAME可靠地将转移性黑色素瘤与GNET和MMNST区分开来,支持其在这种区分中的应用。然而,其在EMPNST中的特异性降低限制了其在这种情况下的独立诊断价值,强调了多模式方法的必要性。
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来源期刊
CiteScore
3.20
自引率
5.90%
发文量
174
审稿时长
3-8 weeks
期刊介绍: Journal of Cutaneous Pathology publishes manuscripts broadly relevant to diseases of the skin and mucosae, with the aims of advancing scientific knowledge regarding dermatopathology and enhancing the communication between clinical practitioners and research scientists. Original scientific manuscripts on diagnostic and experimental cutaneous pathology are especially desirable. Timely, pertinent review articles also will be given high priority. Manuscripts based on light, fluorescence, and electron microscopy, histochemistry, immunology, molecular biology, and genetics, as well as allied sciences, are all welcome, provided their principal focus is on cutaneous pathology. Publication time will be kept as short as possible, ensuring that articles will be quickly available to all interested in this speciality.
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