Table 1: Classification of Tavassoli [18].

Proposed classificationCurrent designationNecrosisExcised margin

DIN 1aIDHNoneNegative

AIDH, flat monomorphic? Negative
DCIS, grade 1 (crib/micropap)Positive
DIN 1bDCIS, grade 2 + Positive
(crib/micropap + necrosis or atypia) +
Special type—specify

DIN 3bDCIS Grade 3 + + + Positive
(Anaplastic DCIS) ±