硝子体手術により切除した網膜下増殖組織の電子顕微鏡的観察

Ultrastructure of subretinal proliferative tissue obtained by vitrectomy

　増殖性硝子体網膜症，増殖糖尿病網膜症など12例の硝子体手術の際に摘出した網膜下増殖組織を光学顕微鏡および電子顕微鏡で観察した。網膜下増殖組織は，細胞外基質が粗な網状の5例，密な3例，そのほかの4例に大別したが，きわめて多様であった。細胞はマクロファージ様，線維芽細胞様紡錘形，大型明細胞など多彩であったが，10例で網膜色素上皮細胞と同定した。フィブリンで構成された網状の細胞外基質に紡錘形あるいはマクロファージ様の網膜色素上皮細胞が伸展する像が観察され，これを網膜下増殖組織の初期の形態と考えた。今回の観察結果から，剥離した網膜下に形成されたフィブリン網を足場として，網膜色素上皮細胞が増殖し，網膜下増殖組織が形成されるという過程を推測した。

We removed subretinal proliferative tissue in 12 eyes during vitreous surgery. Retinal detachment was present in all the eyes secondary to blunt trauma, retinopathy of prematurity, giant tear, diabetic retinopathy or idiopathic vitreous hemor-rhage. The light microscopic features varied from loose reticular structure to densely condensed strands. The subretinal tissue contained cells simulating macrophages, fibroblasts, epithelial cells and spindle-shaped ones. These cells weredefined as retinal pigment apithelial cells in 10 eyes.The tissue also contained fibrin and collagen as components. There were 4 eyes manifesting retinal pigment epithelial cells simulating macrophages or spindle cells and embedded in loose reticular struc-tures of fibrin. This tissue type appeared to be early manifestations of subretinal proliferation. The find-ings led to the hypothesis that fibrin is the primary component of subretinal proliferative tissue and that retinal pigment epithelial cells secondarily proliferate along the fibrinous tissue as scaffold.