he ABC immunobistochemical metheod was performed on 29 cases of emdometrial atypicalhyperplasia(AH)and 32 cases of well differentiated carrcinoma(WDCA)to detect collagenⅣ

CEAand lactoferin

The results indicated tbat 25/29 AH cases had intact epithelial basementmembranes with Linear staining of collagen Ⅳ

and 8/32 WDCA leasions had disrupted basementmembranes with fragment staining of collagen Ⅳ. CEA

Lactoferrin strong staining were foundmainly in WDCA cells

with weak reaction seen in AH cells.The reslts surggest that the collagen Ⅳ detection is of practical value in the differential diagnosisbetween AH and WDCA

Ultrastructurally

most carcinomatous cells exhibited poorly developedmocrovilli and eXtreme polymorphous nuclei.The basal lamina disruption can be easily identified. In AH cells

the nucrovilli were numerous and well developed

and the neuclear pleomorphism wasnot obvious

The basal lamina of AH presented as a continuing line.