扁桃体滤泡树突细胞肉瘤1例并文献复习

目的探讨扁桃体滤泡树突细胞肉瘤(follicular dendritic cell sarcoma,FDCS)的临床病理学特点,降低滤泡树突细胞肉瘤误诊率。方法采用HE、免疫组化及原位杂交法观察扁桃体FDCS的临床病理学及免疫表型,并复习相关文献。结果镜下见肿瘤细胞呈结节状和漩涡状排列,细胞卵圆形~梭形,上皮样,与鳞状上皮相似;核卵圆形,染色质细颗粒状,有小核仁。瘤细胞间混有小淋巴细胞。免疫表型:CD21、CD23和vimentin均弥漫强阳性,S-100、CD68、CK17及CD45均阴性,EBER原位杂交检测阴性。结论 FDCS是一种少见的低度恶性肿瘤,发生于扁桃体者更为罕见,诊断依赖病理组织学及免疫表型;易误诊,需与鳞状细胞癌鉴别。     

脾脏炎性假瘤样滤泡树突细胞肿瘤的临床病理学特征

目的探讨炎性假瘤样滤泡树突细胞肿瘤的临床病理学特征。方法观察1例脾脏的炎性假瘤样滤泡树突细胞肿瘤的大体和光镜形态,免疫组织化学EnVision法检测CD21、CD23、CD35、Clusterin、S-100、波形蛋白、平滑肌肌动蛋白（SMA）、CD1a、CD68、间变型淋巴瘤激酶（ALK）、CD30、CD31、CD34、CD3、CD20,原位杂交检测EBER,并结合文献复习分析其生物学行为和病因机制。结果炎性假瘤样滤泡树突细胞肿瘤好发于腹腔内脏器,尤以肝、脾多见,患者以女性为主。一般肿瘤较大,切面灰白质韧,中心有出血或坏死。镜下大量淋巴细胞、浆细胞背景中见弥散分布的滤泡树突细胞,形似炎性假瘤。高倍镜下滤泡树突细胞胞质淡染,胞界不清,核卵圆形或杆状,染色质空泡样或点彩状,居中可见小的紫色核仁。部分瘤细胞显示异型性,核膜皱褶,染色质粗糙,核仁明显。核分裂象罕见。免疫组织化学：梭形瘤细胞波形蛋白强阳性;Clusterin、SMA、CD68均阳性;CD35局部弱阳性,S-100弱阳性;CD21、CD23、CD1a、ALK、CD30、CD31、CD34均阴性。背景淋巴细胞CD3阳性,灶性区CD20阳性。原位杂交：梭形瘤细胞EBER阳性。结论炎性假瘤样滤泡树突细胞肿瘤是一种罕见的低度恶性肿瘤,与EB病毒感染有关。     

霍奇金淋巴瘤侵犯骨髓的形态学及免疫表型分析

目的探讨霍奇金淋巴瘤侵犯骨髓的形态学、免疫表型特征及诊断与鉴别诊断要点。方法通过骨髓活检组织行HE、免疫组化Eli Vision两步法染色及EBER原位杂交,并结合临床资料进行分析。结果 10例经典型霍奇金淋巴瘤均可见由肿瘤性的大细胞(HRS细胞)及背景细胞和造血细胞形成的实体性或肉芽肿样结构;2例结节性淋巴细胞为主型霍奇金淋巴瘤可见由"爆米花"样细胞及背景细胞和造血细胞形成的实体瘤样结构。骨髓增生明显活跃者8例,造血组织三系增生减低者4例。有病态造血变化者8例表现为粒、红、巨三系分化及成熟异常,原始造血细胞增多。PET/CT示4例有骨质破坏,且伴骨髓纤维化及造血组织细胞三系减低的现象。免疫表型:2例结节性淋巴细胞为主霍奇金淋巴瘤CD20、BCL-6、OCT-2、CD45、EMA及BOB-1均阳性,而CD30、CD15均阴性;10例经典型霍奇金淋巴瘤CD30阳性,6例CD15阳性,9例Pax-5弱阳性,3例OCT-2阳性,3例CD20阳性。对8例混合细胞型经典型霍奇金淋巴瘤行EBER原位杂交检测,其中4例阳性。结论霍奇金淋巴瘤侵犯骨髓时,造血组织有病态造血的变化,尤其是粒细胞形态学的变化易与肿瘤性的大细胞混淆,在免疫表型上CD15亦阳性,需借助Pax-5加以鉴别,因为大多数肿瘤细胞Pax-5弱阳性,而粒细胞不表达Pax-5。骨髓活检可确诊霍奇金淋巴瘤骨髓浸润,对于无淋巴结侵犯或取材受限(如原发于呼吸道、纵隔等)的患者,在PET/CT引导下骨髓穿刺活检不仅可对其直接进行病理诊断,还有望提高淋巴瘤侵犯骨髓的检出率。     

肝脏炎性假瘤与炎性假瘤样滤泡树突状细胞肿瘤的病理学诊断

目的探讨肝脏炎性假瘤及肝脏炎性假瘤样滤泡树突状细胞肿瘤的临床病理学特征及诊断、鉴别诊断要点。方法对肝脏炎性假瘤及肝脏炎性假瘤样滤泡树突状细胞肿瘤各1例进行临床病理分析、免疫组织化学染色及EBV-encoded RNA（EBER）原位杂交检测。结果肝脏炎性假瘤的临床症状包括右上腹不适或疼痛、发热、肝肿大、体重减轻等。大体肿瘤呈实性，境界清楚；镜下肿瘤细胞呈梭形，波浪状排列，其间可见大量淋巴细胞及浆细胞浸润以及散在分布的大的多形性细胞。核仁明显。肝脏炎性假瘤样树突状细胞肿瘤的临床症状、影像学表现及镜下表现均与肝脏炎性假瘤十分相似。但肿瘤细胞边界不清，胞质嗜酸性，除R—S样细胞外，还可见到不少形态怪异的巨细胞，且免疫表型CD21、CD35阳性。EBER（EBV—encoded RNA原位杂交）阳性。结论肝脏炎性假瘤样滤泡树突状细胞肿瘤是罕见的肿瘤，诊断时需注意与肝脏梭形细胞肿瘤甚至霍奇金淋巴瘤鉴别，树突状细胞免疫标记CD21、CD35阳性，特别是EBER原位杂交阳性有助于诊断。     

富于PD-1阳性T细胞的滤泡间弥漫大B细胞淋巴瘤1例临床病理分析

目的探讨富于PD-1阳性T细胞的滤泡间弥漫大B细胞淋巴瘤(diffuse large B cell lymphoma,DLBCL)的临床病理学和免疫表型特征及鉴别诊断。方法应用HE和免疫组化染色、EBER原位杂交及基因克隆性重排技术检测1例罕见的富于PD-1阳性T细胞的滤泡间DLBCL,并复习相关文献。结果镜下见淋巴结内增生的淋巴滤泡散在分布,滤泡间区增宽明显伴多形性细胞浸润,包括异型的中心母细胞和免疫母细胞样大细胞、小淋巴样细胞、嗜酸性粒细胞和组织细胞。免疫表型:滤泡间区异型大细胞CD20、PAX5、MUM1一致强阳性表达,CD3、CD5、CD10、BCL-6、CD30和CD15均阴性,背景小淋巴样细胞多为PD-1阳性的T细胞。此外,EBER原位杂交阴性,免疫球蛋白基因重排示B细胞单克隆性增生,T细胞受体基因未见单克隆性重排。结论滤泡间DLBCL,特别是伴有PD-1阳性的T细胞背景,其诊断具有挑战性。认识DLBCL这一罕见生长方式很重要,需与包括反应性免疫母细胞增生性疾病、血管免疫母细胞性T细胞淋巴瘤、滤泡间霍奇金淋巴瘤和其它富于PD-1阳性T细胞的大B细胞淋巴瘤等类似病变鉴别。     

传染性单核细胞增生症淋巴结病病理诊断与鉴别诊断

目的 探讨传染性单核细胞增生症淋巴结病的病理形态学特点及诊断与鉴别诊断要点.方法 收集3例传染性单核细胞增生症淋巴结病(均为会诊病例:1例原单位诊断为间变性大细胞淋巴瘤,1例诊断为经典型霍奇金淋巴瘤,另1例未能定性),观察和分析其临床、病理组织学和免疫表型,并对病变淋巴结做EB病毒原位杂交检测.结果 3例患者中男性2例,女性1例,平均年龄15岁,平均病程16天;3例患者均表现为颈部淋巴结肿大,1例伴有低热及咽部疼痛.术后均未予特殊治疗,随访时间分别为5、9、18个月,无1例复发.镜检、免疫表型及EBV检测:淋巴结基本结构不同程度破坏,滤泡外免疫母细胞样大细胞增生,其大多数CD3、CD45RO、CD43、CD30均(+),CD15、EMA和ALK1(-),3例EBER均(+).结论 传染性单核细胞增生症淋巴结病的副皮质区有较多免疫母细胞增生,易过诊,但其临床特征、病理特点和免疫表型与大细胞淋巴瘤不同;结合EBV检测有助于其诊断.     

儿童腹腔非霍奇金B细胞淋巴瘤的临床病理及免疫表型分析

目的 探讨儿童腹腔原发性非霍奇金B细胞淋巴瘤的临床病理、免疫表型与EBER特征及其病理诊断和鉴别诊断.方法 按WHO(2008年)淋巴瘤分类标准分析74例儿童腹腔原发性非霍奇金B细胞淋巴瘤的临床病理资料,制备组织芯片,进行免疫组织化学SP法染色,EBER原位杂交和c-myc基因荧光原位杂交,观察CD20、CD79a、CD3、CD10、bcl-6、MUM1、bcl-2、CD43、CD38和Ki-67蛋白的表达和EBER表达特征,并区分伯基特淋巴瘤(BL)、弥漫性大B细胞淋巴瘤(DLBCL)和介于BL和DLBCL之间的不能分类的B细胞淋巴瘤(DLBCL/BL)病理类型,在DLBCL中再区分其生发中心B细胞型(GCB)和非生发中心B细胞型(non-GCB)的分化特征.结果 儿童腹腔非霍奇金B细胞淋巴瘤中BL为65例(87.8%),DLBCL为4例(5.4%),DLBCL/BL为5例(6.8%).临床以腹痛、腹部包块、肠梗阻及肠套叠为主要发病症状.BL免疫组织化学表达CD20(65例)、CD79a(65例)、CD10(63例)、bcl-6(62例)、MUM1(15例)、CD43(46例)和CD38(63例);不表达CD3、bcl-2;27例(41.6%)EBER阳性;54例(93.0%)c-myc基因位点断裂.DLBCL免疫组织化学表达CD20(4例)、CD79a(4例)、CD10(3例)、bcl-6(2例)、MUM1(2例)、bcl-2(3例)、CD43(2例)、CD38(2例);不表达CD3;其中2例GCB,2例non-GCB;EBER阴性;1例c-myc基因位点断裂.DLBCL/BL免疫组织化学表达CD20(5例)、CD79a(5例)、CD10(5例)、bcl-6(4例)、MUM1(3例)、CD43(5例)、CD38(3例),不表达CD3和bcl-2;4例EBER阴性;3例c-myc基因位点断裂.结论 儿童腹腔非霍奇金B细胞淋巴瘤具有侵袭性生长的特点,以BL为主要病理类型.临床以腹痛、腹部包块、肠梗阻及肠套叠为主要发病症状,主要累及回盲部肠组织及周围系膜淋巴结,病理形态、免疫表型、EBER、c-myc基因的检测对BL、DLBC及DLBCL/BL淋巴瘤的诊断和鉴别诊断有重要作用.     

淋巴细胞丰富型经典型霍奇金淋巴瘤的病理诊断与鉴别诊断

目的 探讨淋巴细胞丰富型经典型霍奇金淋巴瘤(lymphocyte-rich classical hodgkin lymphoma,LRCHL)病理形态学特点、免疫表型、诊断与鉴别诊断.方法 观察和分析3例LRCHL的临床、组织病理学和免疫表型特征,并对病变淋巴结行EBV原位杂交检测.结果 3例患者中男性2例,女性1例,平均年龄49岁.临床表现以淋巴结肿大为主,均无B症状.镜检、免疫表型和EBV检测:淋巴结呈不规则小结节状增生,可见残留滤泡和增宽的套区,套区内见R-S样细胞,2例上皮样组织细胞浸润明显,均未见嗜酸性粒细胞和中性粒细胞.R-S样细胞CD30均阳性,2例CD15阳性,1例CD20异质性表达,1/2例EBV阳性.结论 LRCHL是经典型霍奇金淋巴瘤(classical hodgkin lymphoma,CHL)少见的一种亚型,具有独特的临床特征和预后,诊断上需与结节性淋巴细胞为主型霍奇金淋巴瘤(nodular lymphocyte predominant hodgkin lymphoma,NLPHL)、富于T/组织细胞的弥漫大B细胞淋巴瘤(T cell/histiocyte-rich large B-cell lymphoma,THRLBCL)、血管免疫母细胞性T细胞淋巴瘤(angioimmunoblastic T-cell lymphoma,AILT)及CHL的其它亚型相鉴别.     

肝脏原发黏膜相关淋巴组织结外边缘区淋巴瘤及肝脏假性淋巴瘤的临床病理特征北大核心CSCD

目的 探讨肝脏原发黏膜相关淋巴组织结外边缘区（MALT）淋巴瘤和肝脏假性淋巴瘤的临床病理特征、鉴别诊断.方法 收集2012年1月至2017年3月就诊于南京医科大学第一附属医院的3例肝脏原发MALT淋巴瘤和2例肝脏假性淋巴瘤患者资料,行HE和免疫组织化学EnVision法染色观察组织学形态,采用原位杂交法检测EB病毒编码小RNA,采用荧光原位杂交（FISH）技术检测MALT1基因,采用免疫球蛋白（Ig）基因重排检测技术分析克隆性基因重排情况,并复习相关文献.结果 3例MALT淋巴瘤,肿瘤结节状浸润汇管区,浸润及包绕周围肝组织并融合成结节或片状,多量小胆管陷入、散布其间伴淋巴上皮病变.瘤细胞围绕增生的淋巴滤泡,主要为中心细胞样和单核样B细胞,其中1例可见簇状上皮样组织细胞.瘤细胞CD20和PAX5阳性,不表达CD5、CD23、CD10、bcl-6及cyclin D1.2例肝脏假性淋巴瘤,病灶呈境界清楚的孤立性结节,其中1例可见部分纤维包膜.小胆管仅见于病灶周边,且缺乏淋巴上皮病变.淋巴组织增生以淋巴滤泡增生为主,缺乏明显异型性和单核样B细胞形态.免疫组织化学染色示增生的淋巴组织由B细胞和T细胞混合.Ig基因重排检测发现,3例肝脏原发MALT淋巴瘤呈单克隆性B细胞增生,而在2例假性淋巴瘤示多克隆性增生.FISH检测发现2例MALT淋巴瘤存在MALT1基因断裂.所有病例EBER原位杂交均为阴性.结论 肝脏原发MALT淋巴瘤和假性淋巴瘤均属肝脏罕见的淋巴组织增生性病变,两者具有重叠的组织学形态及免疫表型特征,互为首要鉴别诊断.综合分析组织形态、免疫表型和基因重排有助于区分两者.     

滤泡树突细胞肉瘤6例临床病理分析

目的探讨滤泡树突细胞肉瘤的病理诊断及鉴别诊断。方法应用组织病理学及免疫组化观察6例(包括2例细针穿刺组织)滤泡树突细胞肉瘤的特点,并结合文献探讨其病理形态及鉴别诊断等。结果镜检肿瘤细胞为梭形、卵圆形,胞质丰富,可见小核仁,细胞呈片状、束状、编织状或漩涡状排列。免疫组化显示肿瘤细胞特异性地表达CD21、CD23、CD35、fascin、clusterin、D2-40、EMA,部分病例表达CXCL-13。结论滤泡树突细胞肉瘤是少见的低度恶性肿瘤,形态学上表现为梭形细胞呈漩涡状脑膜瘤样结构,CD21、CD35、EMA对于确诊有重要意义。Fascin、clusterin及CXCL-13可能成为滤泡树突细胞肉瘤的新标记物。     

Expression of CD30 (Ber-H2) in nasopharyngeal carcinoma, undifferentiated type and lymphoepithelioma-like carcinoma. A comparison study with anaplastic large cell lymphoma

AIMS: Undifferentiated nasopharyngeal non-keratinizing carcinoma (UNPC), formerly known as lymphoepithelioma, frequently metastasizes at an early stage to regional lymph nodes and, thus, may be difficult to distinguish from Hodgkin's lymphoma (HL) or anaplastic large cell lymphoma (ALCL). CD30 expression is a useful diagnostic stain in both HL and ALCL, but its expression in UNPC deserves clarification. The aim of this study was to evaluate CD30 expression in UNPC and lymphoepithelioma-like carcinoma (LELC) from other anatomic locations and compare it with ALCL and squamous cell carcinoma (SCC). METHODS AND RESULTS: CD30 immunoreactivity was examined in 38 cases of primary or metastatic UNPC, six cases of LELC, 10 cases of SCC and seven cases of ALCL. CD30 immunoreactivity was observed in four of 38 (10.5%) cases of UNPC. CD30 staining was absent in all cases of LELC (0/6) and SCC (0/10). All cases of ALCL (7/7) were strongly positive for CD30. CONCLUSIONS: The majority of cases of UNPC are immunohistochemically negative for CD30; however, a small subset of cases expresses CD30 antigen. These findings provide additional evidence that CD30 expression is not restricted to neoplasms of lymphoid origin. This should be taken into consideration when interpreting CD30 immunohistology and the possibility of UNPC.     

American Registry of Pathology Expert Opinions: Immunohistochemical evaluation of classic Hodgkin lymphoma

The diagnosis of classic Hodgkin lymphoma requires immunohistochemical confirmation in most cases and one can argue for these studies as standard-of-care in the diagnostic workup. The authors propose a panel of studies for primary identification of CHL to include: CD3, CD20, CD15, CD30 and PAX5. When pattern discordances are identified, additional assessment is recommended. In the case of overexpression of B lineage markers by Hodgkin/Reed-Sternberg cells, or a differential diagnosis that includes large B-cell lymphoma or variants, additional markers recommended are: CD45, OCT2, BOB1, CD79a and MUM1/IRF4. If primary mediastinal large B cell lymphoma is considered in the differential diagnosis, suggested additional markers include: P63, CD23, CD45 and CD79a. When considering a differential diagnosis that includes anaplastic large cell lymphoma we suggest: ALK, CD45, pan T cell antigens (such as CD2, CD5, CD7, and CD43), and cytotoxic markers (granzyme, perforin, and TIA1). If peripheral T cell lymphoma or T cell lymphomas of follicular helper origin are considered in the differential diagnosis, the following panel is recommended: pan T cell antigens, CD4, CD8, one or more follicular dendritic cell markers, and assessment for Epstein-Barr virus (EBV) infection, preferably EBV encoded RNA (EBER) as assessed by in situ hybridization When the differential diagnosis includes nodular lymphocyte predominant Hodgkin lymphoma, recommended additional studies include OCT2, CD21 and/or CD23, PD1, and assessment for EBV infection. The authors recognize that these panels may not be adequate to completely characterize other lymphomas, but these panels will usually be sufficient to distinguish classic Hodgkin lymphoma from other lymphoma types.     

Epstein-Barr virus-associated lymphoproliferative disorder presenting with classical Hodgkin lymphoma and developing as peripheral T-cell lymphoma 9 years later: a case report of composite lymphoma

We describe a patient who was diagnosed with classical Hodgkin lymphoma (CHL) at 67-years-old and peripheral T-cell lymphoma, not otherwise specified (PTCL) at 76-years-old, and died 5 months later. Both tumors showed prominent epithelioid cell reaction admixed with neoplastic cells. Hodgkin and Reed-Sternberg cells in the swollen lymph node were positive for CD30 and EBV-encoded RNA (EBER). PTCL cells in the skin tumor were positive for cytoplasmic CD3ε, CD4 and EBER. A rearrangement band of the T-cell receptor gene was detected in the skin tumor. This case is the first documented EBV-associated composite lymphoma composed of CHL and PTCL. The patient may show the possibility that both EBV infection and/or immunodeficiency induce the development of CHL and PTCL.     

系统性间变性大细胞淋巴瘤的免疫组织化学特征

目的:探讨系统性间变性大细胞淋巴瘤(anaplastic large cell lymphoma,ALCL)的免疫组织化学特征.方法:回顾性分析48例系统性ALCL的免疫组织化学和10例系统性ALCL原位杂交技术检测EBER(EBV-encoded small RNA)的结果.结果:48例系统性ALCL的肿瘤细胞均表达CD30,而间变性淋巴瘤激酶(anaplastic lymphoma kinase,ALK)在41.7％(20/48)的病例阳性,其他指标阳性率为CD2为65.0％(26/40),CD3为36.2％(17/47),CD4为72.7％(16/22),CD5为42.9％(15/35),CD7为16.7％(5/30),上皮细胞膜抗原(epithelial membrane antigen,EMA)为65.6％(21/32),T细胞胞质内抗原(T-cell intracellular antigen-1,TIA-1)为79.2％(19/24),颗粒酶B(granzyme B-producing Breg,GrB)为70.0％(14/20).所有病例的B细胞标志(CD20,PAX5,CD79a)均阴性.10例系统性ALCL有2例出现部分肿瘤性大细胞EBER阳性.结论:CD30和ALK是诊断ALCL关键及较为特异的免疫指标;有时出现人类疱疹病毒第四型(Epstein-Barr virus,EBV)感染并不能排除ALCL的诊断.     

滤泡树突状细胞肉瘤的临床病理观察

目的 探讨和分析滤泡树突状细胞肉瘤(FDCS)的临床病理特点及鉴别诊断.方法 应用组织学、免疫组织化学(EnVision法)标记及EBER原位杂交,对8例FDCS进行临床和组织病理学分析,并复习相关文献.结果 8例FDCS中男性5例,女性3例,平均年龄50岁.发生部位淋巴结4例,扁桃体、鼻咽部、肝、脾各1例.组织学:瘤组织呈席纹状、束状、弥漫性、旋涡状或结节状,肿瘤细胞呈合体样,境界不清,胞质较丰富,均质嗜伊红或细颗粒状,核呈卵圆形、短梭形或圆形,染色质稀疏或呈空泡状、点彩状,核仁明显,核分裂象多少不等,肿瘤细胞间见有散在淋巴细胞混杂.间质内可见假血管腔及血管周围淋巴鞘现象.其中肝脏1例以大量小淋巴细胞弥漫分布为背景,梭形或卵圆形的瘤细胞散在分布其中,瘤细胞核染色质细腻,部分区域细胞有轻度异形,核不规则、空泡状,有核仁.免疫组织化学瘤细胞均表达CD21、CD35、clusterin,部分表达CD68、上皮细胞膜抗原、S-100及内皮生长因子受体,Ki-67不同程度表达.EBER两例表达.结论 FDCS是一种非常少见的恶性肿瘤,易复发和转移,明确诊断需要结合病理形态学和免疫表型.     

Dendritic cell sarcomas/tumours of the breast: report of two cases

Extranodal follicular dendritic cell sarcoma/tumours (FDCS/Ts) and interdigitating dendritic cell sarcoma/tumours (IDCS/Ts) are rare neoplasms. We present two cases of FDCS/T and IDCS/T of the breast. The FDCS/T case (case 1) presented in a 31-year-old woman and the IDCS/T case (case 2) in a 67-year-old woman who both showed a firm lump in the left breast. The FDCS/T lesion superficially appeared as an anaplastic carcinoma and the IDCS/T was reminiscent of a spindle cell sarcomatoid carcinoma. Nevertheless both lesions were negative for keratins while case 1 displayed neoplastic cells strongly positive for CD21, vimentin and focally for CD68 and S-100 protein. The tumour cells of case 2 were positive for S-100, CD68 and CD45. In breast, an unusual keratin negative tumour composed predominantly of spindle cells arranged in fascicles, storiform pattern or whorls with a lymphoid rich stroma should raise suspicion for FDCS/Ts or IDCS/Ts. The distinction from malignant tumours with similar features is discussed.     

Hodgkin lymphoma with an interfollicular growth pattern: A clinicopathologic study of 8 cases

Classic Hodgkin lymphoma (CHL) has four subtypes. Different morphologic variations can be seen in lymph nodes involved by CHL. Primary interfollicular (IF) involvement is not considered a separate subtype but an unusual diagnostically challenging morphologic variant. Our aim was to study the prevalence of IF growth pattern and coexistence of other morphologic variants in lymph nodes involved by CHL, to investigate the diagnostic challenges and clinical importance of this growth pattern, and to find helpful histologic clues in cases with subtle morphologic features to help avoid misinterpretation and missed diagnosis. We performed a retrospective review study over 10 years. We searched for diagnosed cases of nodal CHL. We retrieved and reviewed cases of CHL with IF involvement. The clinical and pathologic features of each case were collected and compared. We found 103 cases of CHLs. Eight cases (7.8%) demonstrated IF growth patterns. The age range was between 3 and 48 years with an average age of 26 years. The male to female ratio was 7:1. Six cases were mixed cellularity HLs. Three cases had associated epithelioid granulomas, one had follicular involvement and one had an associated. HHV-8 negative plasma cell rich Castleman disease. One case was initially missed as benign follicular hyperplasia, one case was referred as CD and three cases were initially suspected as HL. IF growth pattern in nodal CHLs can be missed because it can be mild and focal with subtle morphologic features. The presence of epithelioid histiocytes, eosinophils and other coexistent morphologic variants are helpful histologic clues. In doubtful cases, immunohistochemistry study is essential. The majority were early stage cervical node MCHLs in young adults and children. Pathologists should be aware of this possibility when examining reactive lymph nodes. The clinical significance is limited and needs further validation by larger studies.     

Follicular dendritic cell sarcoma of small intestine with aberrant T-cell marker expression

Follicular dendritic cell sarcoma (FDCS) is an uncommon neoplasia usually occurring in lymphoid tissue. Herein is presented a case of FDCS of the small intestine with positivity for T-cell antigen, simulating T-cell lymphoma. An 82-year-old man consulted a doctor for a 1 week history of epigastric pain. Imaging indicated a mass in the small intestine. Malignant lymphoma was suspected because of high serum levels of soluble interleukin-2 receptor, and resection of the tumor was performed. Microscopically the tumor consisted of large pleomorphic cells with reactive small lymphocytes. Most of the nuclei of the tumor cells were round or ovoid, and some of the tumor cells also had spindle-shaped nuclei. Although the tumor cells were diffusely positive for CD45RO and CD4 on immunohistochemistry, negativity for pan-T-cell markers and CD56 was unusual for T-cell lymphoma of intestinal origin. Additional immunohistochemistry demonstrated that the tumor cells were positive for follicular dendritic cell markers including CD23, CD35 and CAN.42, and diagnosis of FDCS was made. To the authors' knowledge this is the first case of FDCS aberrantly expressing CD45RO; FDCS expressing T-cell markers can be a pitfall for diagnosis of FDCS.     

Folliculocentric B-cell-rich follicular dendritic cells sarcoma: a hitherto unreported morphological variant mimicking lymphoproliferative disorders

We report three cases of follicular dendritic cell sarcoma (FDCS) showing a hitherto undescribed histological pattern consisting of nodular tumor growth associated with small B lymphocytes. FDCS tumor cells consistently showed large epithelioid features and were intermingled with small lymphocytes in the nodules in two cases, whereas they formed cohesive aggregates surrounded by lymphocyte mantle in the other. These features were easily confused with lymphomatous proliferations and, in particular, subtypes of Hodgkin lymphoma, high-grade follicular lymphoma, and germinotropic large B-cell lymphomas. The diagnosis was established by the use of a broad panel of antibodies that showed a variable expression of the FDC markers CD21, CD23, CD35, clusterin, podoplanin, claudin 4, epidermal growth factor receptor, and CXCL13. The associated B lymphocytes revealed a mantle zone B phenotype, with expression of CD20 and PAX5, together with TCL1 and IgD. Of notice, in all cases, morphological features suggesting hyaline-vascular Castleman disease were recognized in the interfollicular areas, containing scattered epithelioid cells similar to those found in the nodules, thus providing a useful clue for FDCS diagnosis. Of the 3 cases, 1 presented multiple recurrences unresponsive to chemotherapy and radiotherapy and finally died of disease 14 years after diagnosis. This study further emphasizes the extreme variability of morphological presentation of FDCS and expands the spectrum of lesions showing a nodular growth pattern occurring in human lymph nodes.