화살표 ccl : apical snoutsEarliest stage of breast neoplasiaPrecursor of ADH / DCIS / BC​HistopathologyTDLU with enlarged &ampdilated ccl acini, Lined by columnar epithelial cellsIrregular contoursApical snoutsNo cytological atypiaOvoid nuclei, Even chromatin, inconspicuous nucleoli (benign)Atypia ccl 있으면 FEA1~2 cell layers thick Ϝolumnar cell change>2 cell layers thick Ϝolumnar cell hyperplasiaER + , ccl CK 5/6 -​Flat epithelial atypia (FEA)Low-grade cytological atypiaApical snout +No micropapillary formation, No bridges, no arcadesMay ccl have one to several layers of midly atypical, cuboidal ~ columnar cellsround nuclei, inconspicuous nucleoliLow grade ccl DCIS와 비슷함ER + , CK 5/6 -​CCL &ampFEA are often associated with other benign changesCystsEpithelial proliferative ccl lesions* ADH vs DCISUDHADHDCISMyoepithelial cells◎OXCell populationHeterogeneousMore uniform than UDHMonomorphicRoman bridgeXOXNuclear overlappingOXXCribriform길쭉한 모양섞임Swiss cheese (거의 동그람)* DCIS ccl pattern이더라도 duct 하나를 통째로 차지하지 않거나, 2mm 이하, duct 하나에 국한된 경우, ADH로 간주.