Abstract：
This series describes the immunopathologic features of posterior embryotoxon (PE) and demonstrates that it is not an anterior displaced Schwalbe\'s line as commonly described, but a peripheral corneal stromal nub variable in location with abnormal extracellular matrix.
Case series.
Archived specimens from patients with PE.
Sections from archived formalin-fixed, paraffin-embedded specimens (n = 9; 7 autopsy and 2 trabeculectomy specimens) were examined by light microscopy. Immunohistochemistry was performed on 5 specimens to characterize the extracellular matrix composition of PE.
Posterior embryotoxon appeared as nubs of whorled collagen extending from the corneal stroma, lined in some instances, by Descemet membrane. These nubs were located anterior to Schwalbe\'s line (n = 4), posteriorly (n = 1), partially embedded in the trabecular meshwork (n = 1), or at Schwalbe\'s line (n = 2). Qualitatively, collagen I labeling of the PE stroma was similar or weaker than the corneal stroma, whereas collagen III staining was focal and slightly more intense compared with the corneal stroma. Lumican and keratan sulfate staining was similar or less intense in PE compared with the corneal stroma.
Identify location of PE and its immunohistochemical features.
In contrast to the widely accepted definition of PE as a prominent, anteriorly displaced Schwalbe line, histologic evidence suggests that it is a direct extension of the corneal stroma with variable locations that may displace the attenuated Descemet membrane when located anterior to or at Schwalbe\'s line. Immunohistochemical examination revealed that the composition of PE\'s extracellular matrix was similar to corneal stroma but with some variability in staining intensity.
Case series.
Archived specimens from patients with PE.
Sections from archived formalin-fixed, paraffin-embedded specimens (n = 9; 7 autopsy and 2 trabeculectomy specimens) were examined by light microscopy. Immunohistochemistry was performed on 5 specimens to characterize the extracellular matrix composition of PE.
Posterior embryotoxon appeared as nubs of whorled collagen extending from the corneal stroma, lined in some instances, by Descemet membrane. These nubs were located anterior to Schwalbe\'s line (n = 4), posteriorly (n = 1), partially embedded in the trabecular meshwork (n = 1), or at Schwalbe\'s line (n = 2). Qualitatively, collagen I labeling of the PE stroma was similar or weaker than the corneal stroma, whereas collagen III staining was focal and slightly more intense compared with the corneal stroma. Lumican and keratan sulfate staining was similar or less intense in PE compared with the corneal stroma.
Identify location of PE and its immunohistochemical features.
In contrast to the widely accepted definition of PE as a prominent, anteriorly displaced Schwalbe line, histologic evidence suggests that it is a direct extension of the corneal stroma with variable locations that may displace the attenuated Descemet membrane when located anterior to or at Schwalbe\'s line. Immunohistochemical examination revealed that the composition of PE\'s extracellular matrix was similar to corneal stroma but with some variability in staining intensity.
摘要：
本系列描述了后胚毒素（PE）的免疫病理学特征，并证明它不是通常描述的前移位Schwalbe系，但周围角膜基质结节位置可变，细胞外基质异常。
案例系列。
来自PE患者的存档标本。
从归档福尔马林固定，石蜡包埋的标本（n=9；7例尸检和2例小梁切除术标本）通过光学显微镜检查。对5个样本进行免疫组织化学以表征PE的细胞外基质组成。
后胚毒素表现为从角膜基质中延伸出来的螺旋胶原蛋白结节，在某些情况下，通过Descemet膜。这些结节位于Schwalbe线的前方(n=4)，向后(n=1)，部分嵌入小梁网(n=1)，或在Schwalbe线（n=2）。定性,PE基质的胶原蛋白I标记与角膜基质相似或较弱，而胶原蛋白III染色是局灶性的，与角膜基质相比稍强烈。与角膜基质相比，PE中的Lumican和硫酸角质素染色相似或强度较低。
确定PE的位置及其免疫组织化学特征。
与广泛接受的PE作为突出的定义相反，前部移位的Schwalbe线，组织学证据表明，它是角膜基质的直接延伸，具有可变位置，当位于Schwalbe线前方或上方时，可能会取代衰减的Descemet膜。免疫组织化学检查显示，PE的细胞外基质的组成与角膜基质相似，但染色强度有一定差异。
案例系列。
来自PE患者的存档标本。
从归档福尔马林固定，石蜡包埋的标本（n=9；7例尸检和2例小梁切除术标本）通过光学显微镜检查。对5个样本进行免疫组织化学以表征PE的细胞外基质组成。
后胚毒素表现为从角膜基质中延伸出来的螺旋胶原蛋白结节，在某些情况下，通过Descemet膜。这些结节位于Schwalbe线的前方(n=4)，向后(n=1)，部分嵌入小梁网(n=1)，或在Schwalbe线（n=2）。定性,PE基质的胶原蛋白I标记与角膜基质相似或较弱，而胶原蛋白III染色是局灶性的，与角膜基质相比稍强烈。与角膜基质相比，PE中的Lumican和硫酸角质素染色相似或强度较低。
确定PE的位置及其免疫组织化学特征。
与广泛接受的PE作为突出的定义相反，前部移位的Schwalbe线，组织学证据表明，它是角膜基质的直接延伸，具有可变位置，当位于Schwalbe线前方或上方时，可能会取代衰减的Descemet膜。免疫组织化学检查显示，PE的细胞外基质的组成与角膜基质相似，但染色强度有一定差异。
