Follicular dendritic cell sarcoma: clinicopathologic study of 15 cases with emphasis on novel expression of MDM2, somatostatin receptor 2A, and PD-L1
Follicular dendritic cell sarcoma: clinicopathologic study of 15 cases with emphasis on novel expression of MDM2, somatostatin receptor 2A, and PD-L1
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DOI：
10.1016/j.anndiagpath.2016.05.003
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发表时间：
2016-08-01
影响因子：
2
通讯作者：
Michal, Michal
中科院分区：
文献类型：
--
作者：
Agaimy, Abbas;Michal, Michael;Michal, Michal
滤泡树突状细胞肉瘤是一种罕见的低度恶性肿瘤，具有滤泡树突状细胞的表型。这种罕见的肉瘤常被误诊为多种肿瘤（主要是脑膜瘤），尤其是发生在结节部位。FDCS的诊断主要依靠特征性的组织学表现，辅以免疫组化和电镜检查。在这项研究中，我们回顾了从我们的咨询文件中检索到的15个FDCS，并对它们进行了染色，以确定除了传统FDC标记物之外的新报告或新型标记物（PD-L1，Rb 1，MDM 2和生长抑素受体2A [SSTR 2A]）。患者为7名男性和7名女性（1名未指明），平均年龄为47岁（20-75岁）。肿瘤部位为淋巴结6例，脾脏2例，头颈部淋巴结4例，腹腔2例。治疗采用手术和积极化疗/放疗的可变组合。随访8例，其中4例在1 ~ 10年内死亡。所有肿瘤均表达至少一种FDC标志物：CD 21（8/13）、CD 23（2/13）、CD 35（8/12）、CNA.42（13/14）、Ecterin（8/13）、Fascin（15/15）和D2-40/podoplanin（7/14）。Epstein-Ban-virus（EBER-1/2原位杂交）在10种常规变异体中成功进行，均为阴性。14例中有5例（36%）SSTR 2A强染色，具有独特的膜图案。一些肿瘤周围的残留淋巴滤泡对SSTR 2A的染色类似。13例可评估病例中有7例（54%）在超过5%的肿瘤细胞中显示PD-L1中度至强膜染色。14例中4例（28%）Rb 1抗原丢失。14例中有5例（36%）的肿瘤细胞MDM 2染色低于5%至20%;其中2例荧光原位杂交（FISH）显示扩增。CDK 4除1例弱阳性外均为阴性。这项研究增加了现有的几个临床病理系列FDCS和代表的第一项研究，显示MDM 2扩增在这个实体。我们关于FDCS中SSTR 2A频繁表达的研究结果是新颖的，可能具有潜在的诊断和治疗意义。FDCS中的SSTR 2A表达代表了一个进一步的混淆因素，当考虑脑膜瘤时，它均匀地表达这种受体。腹膜后和/或腹腔内发生的FDCS可能与去分化脂肪肉瘤非常相似，特别是如果MDM 2阳性和/或扩增，因此应仔细评估FDC标志物的表达。(C)2016 Elsevier Inc. All rights reserved.
Follicular dendritic cell sarcoma (FDCS) is a rare low-grade neoplasm with the phenotype of FDC cells. This rare sarcoma has been well known for being mistaken for a variety of neoplasms (mainly meningioma), particularly at extranodal sites. Diagnosis of FDCS mainly relies on characteristic histologic appearance supplemented by immunohistochemistry and electron microscopy. In this study, we reviewed 15 FDCSs retrieved from our consultation files and stained them for newly reported or novel markers (PD-L1, Rb1, MDM2, and somatostatin receptor 2A [SSTR2A]) in addition to conventional FDC markers. Patients were 7 men and 7 women (1 unspecified) with a mean age of 47 years (20-75 years). The tumor site was lymph nodes (6) or spleen (2), both (1) and extranodal sites of head and neck (4) or abdominal cavity (2). Treatment was variable combinations of surgery and aggressive chemotherapy/radiotherapy. Four of 8 patients with follow-up died of disease within 1 to 10 years. All tumors expressed at least 1 FDC marker: CD21 (8/13), CD23 (2/13), CD35 (8/12), CNA.42 (13/14), Clusterin (8/13), Fascin (15/15) and D2-40/podoplanin (7/14). Epstein-Ban-virus (EBER-1/2 in situ hybridization) was performed successfully in 10 conventional variants; all were negative. Five of 14 cases (36%) stained strongly for SSTR2A with a distinctive membranous pattern. Residual lymphoid follicles surrounding some of the tumors stained similarly for SSTR2A. Seven (54%) of 13 assessable cases showed moderate to strong membranous staining for PD-L1 in greater than 5% of the neoplastic cells. The Rb1 antigen was lost in 4 (28%) of 14 cases. MDM2 stained less than 5% to 20% of the tumor cells in 5 (36%) of 14 cases; 2 of them showed amplification by fluorescence in situ hybridization (FISH). CDK4 was negative except for weak staining in 1 of 14 cases. This study adds to the existing few clinicopathologic series on FDCS and represents the first study to show MDM2 amplification in this entity. Our results regarding frequent SSTR2A expression in FDCS are novel and might be of potential diagnostic and therapeutic relevance. SSTR2A expression in FDCS represents a further confusing factor when thinking of meningioma which uniformly expresses this receptor. FDCS occurring within the retroperitoneum and/or the abdominal cavity may closely mimic dedifferentiated liposarcoma, particularly if MDM2 positive and/or amplified and should thus be carefully assessed for expression of FDC markers. (C) 2016 Elsevier Inc. All rights reserved.