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Breast malignant, males, children

In situ carcinoma

Ductal intraepithelial neoplasia (DIN)

Reviewer: Monika Roychowdhury, M.D. (see Reviewers page)
Revised: 24 January 2012, last major update January 2012
Copyright: (c) 2001-2012, PathologyOutlines.com, Inc.


● This terminology avoids use of “carcinoma”, but is not widely used
● Proponents claim it reduces the “artificial separation” between ADH and low grade DCIS (Virchows Arch 2006;449:609)
● If DIN terminology is used in a report, recommended to also reference traditional terminology

Micro description/grading

● Most invasive breast cancer cases are associated with more than one type of DIN
Morphologic subtypes:
     ● Solid
     ● Cribriform
     ● Comedo
     ● Micropapillary
     ● Papillary
     ● Flat

     ● UDH: usual ductal hyperplasia
     ● DIN 1A: flat epithelial atypia
     ● DIN 1B: atypical ductal hyperplasia
     ● DIN 1C: DCIS grade 1 (low grade)
     ● DIN2: DCIS grade 2 (intermediate grade)
     ● DIN3: DCIS grade 3 (high grade)
Source: Tavassoli: Tumours of the Breast and Female Genital Organs (WHO, 2003)

● Initial version as proposed by Tavassoli is below (Mod Pathol 1998;11:140), but was subsequently modified to above:
     ● DIN 1a: usual ductal hyperplasia
     ● Din 1b: flat epithelial atypia
     ● Din 1c: ADH and small grade I DCIS
     ● DIN 2: large grade I and grade II DCIS
     ● DIN 3: grade III DCIS

Additional references

Histologic Subtypes of ductal intraepithelial neoplasia of the breast (DIN): Characteristics and Biology (2009 ASCO Annual meeting)

End of Breast malignant, males, children > In situ carcinoma > Ductal intraepithelial neoplasia (DIN)

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