Basha Basma M, Hsi Eric D
Robert J. Tomsich Pathology and Laboratory Medicine Institute, Cleveland Clinic, Cleveland, OH.
Appl Immunohistochem Mol Morphol. 2019 Jul;27(6):482-489. doi: 10.1097/PAI.0000000000000661.
Vascular transformation of sinuses (VTS) is an uncommon and benign lesion, defined by conversion of lymph node sinuses into complex, anatomizing and endothelial-lined channels. Despite the name of VTS, which implies a change in differentiation from lymphatic to vascular endothelium, very few studies have systematically examined VTS with modern immunohistochemical markers commonly used in clinical laboratories. It is unclear whether endothelial cells in VTS display pure vascular or lymphatic differentiation, or both.
A total of 11 cases with a diagnosis of VTS (identified in the tissue archives of the Cleveland Clinic between 1992 and 2015) were reviewed and confirmed. Twenty cases of benign lymph nodes without specific diagnoses were used as control tissues. Immunohistochemical stains were performed on formalin-fixed, paraffin-embedded lymph node tissue using an automated immunohistochemistry platform with antibodies against CD31, CD34, D2-40, and ERG. Positivity in the VTS lesions was defined as distinct expression in the appropriate cell compartment in ≥20% of cells. In control cases, staining was evaluated in both vascular and lymphatic channels-vascular structures were identified by presence of red cells or well-formed vascular walls and lymphatics by anatomic location and absence of vascular features.
In the VTS lesions, D2-40 expression was absent in the lesional endothelial cells of 5/11 (45%) cases. In the cases lacking D240 expression, uninvolved lymphatic endothelium maintained expression. CD34 expression was also seen in 6/11 (54%), CD31 was seen in 10/11 (90%), and ERG expression was seen in all cases. In all the control cases, D240 expression was exclusively seen in lymphatic endothelial cells and not seen in vascular endothelial cells (eg, vascular channels in the hilum). CD34 was weakly positive in the lymphatic endothelium of only 7/20 (35%) control cases, but expressed in 20/20 (100%) control cases in the vascular endothelium. 20/20 (100%) of control cases showed expression of CD31 and ERG in both vascular and lymphatic endothelium.
VTS lesional endothelial cells demonstrate patterns of vascular markers that show mixed blood vascular and lymphatic features. There appears to be a degree of alignment toward endothelial differentiation with decreased expression of D2-40 in some cases.
窦道血管转化（VTS）是一种罕见的良性病变，其定义为淋巴结窦道转化为复杂的、相互连接且内衬内皮细胞的通道。尽管VTS这个名称意味着从淋巴管内皮细胞向血管内皮细胞的分化改变，但很少有研究使用临床实验室常用的现代免疫组化标志物对VTS进行系统研究。目前尚不清楚VTS中的内皮细胞是表现为单纯的血管分化、淋巴管分化，还是两者皆有。
回顾并确认了11例诊断为VTS的病例（于1992年至2015年间在克利夫兰诊所的组织档案中识别出）。选取20例未明确诊断的良性淋巴结作为对照组织。使用自动免疫组化平台，对福尔马林固定、石蜡包埋的淋巴结组织进行免疫组化染色，所用抗体针对CD31、CD34、D2-40和ERG。VTS病变中的阳性定义为在≥20%的细胞的适当细胞区室中有明显表达。在对照病例中，对血管和淋巴管通道均进行染色评估——血管结构通过红细胞的存在或完整的血管壁来识别，淋巴管则通过解剖位置以及缺乏血管特征来识别。
在VTS病变中，5/11（45%）的病例中病变内皮细胞缺乏D2-40表达。在缺乏D2-40表达的病例中，未受累的淋巴管内皮细胞保持表达。6/11（54%）的病例可见CD34表达，10/11（90%）的病例可见CD31表达，所有病例均可见ERG表达。在所有对照病例中，D2-40表达仅见于淋巴管内皮细胞，而不见于血管内皮细胞（如门部的血管通道）。CD34仅在7/20（35%）的对照病例的淋巴管内皮细胞中呈弱阳性，但在20/20（100%）的对照病例的血管内皮细胞中表达。20/20（100%）的对照病例在血管和淋巴管内皮细胞中均显示CD31和ERG表达。
VTS病变内皮细胞表现出具有混合血管和淋巴管特征的血管标志物模式。在某些情况下，似乎存在一定程度的内皮分化倾向，伴有D2-40表达降低。
