RESUMO
OBJECTIVE@#To investigate the structural characteristics of the cerebral small vessels with an unknown type of pathological lesion (UTPL).@*METHODS@#Contents of beta-amyloid, alpha-actin and collagen IV in cerebral small vessels with UTPL were studied by Congo red staining, immunohistochemical staining and computer image analysis.@*RESULTS@#The low expression levels of alpha-actin and collagen IV (P<0.05) were observed in tunica media of the vessels with UTPL, and no positive expression of beta-amyloid (P>0.05) was observed in these vessel walls. The expressions of proteins mentioned above in UTPL were different from those of cerebral amyloid angiopathy(CAA) and hyaline arteriolosclerosis.@*CONCLUSION@#UTPL was different from CAA or hyaline arteriolosclerosis in pathologic feature.