title: Flat DIN 1 (flat epithelial atypia) on core needle biopsy: 63 cases identified retrospectively among 1,751 core biopsies performed over an 8-year period (1992-1999).
abstract: Uniform management of flat DIN 1 (flat epithelial atypia) on core needle biopsy (CNB) concerning surgical excision or clinical follow-up are lacking. In a retrospective review of 1,751 CNB over an 8-year period, we found 63 cases with flat DIN 1 as the most advanced lesion; follow-up was available in 55 cases. Of the 63 patients, 24 had a subsequent biopsy for 15 days to 10 years after the initial CNB, an infiltrating carcinoma was found in nine (14.3%) patients, seven (11.1%) in the ipsilateral, and two (3.2%) in the contralateral breast. Five underwent an excisional biopsy of the ipsilateral breast within less than 3 months of the initial CNB; none had either an invasive or intraepithelial carcinoma. Based on our findings, we consider flat DIN 1 a marker of slightly increased risk for subsequent development of invasive breast carcinoma. When flat DIN 1 is found on CNB as the most advanced lesion after mammographic correlation, an excisional biopsy is not mandatory; however, close follow-up is advised with repeat mammograms for early detection of any clinically occult carcinoma in the vicinity of flat DIN 1 that may have been missed by the CNB.
authors.affiliation: Department of Pathology, Yale University School of Medicine, P. O. Box 208070, New Haven, CT 06520-8070, USA. maritza.martel@yale.edu
authors.forename: Maritza
authors.initials: M
authors.lastname: Martel
authors.forename: Patricia
authors.initials: P
authors.lastname: Barron-Rodriguez
authors.forename: Idris
authors.initials: I
authors.lastname: Tolgay Ocal
authors.forename: Jorge
authors.initials: J
authors.lastname: Dotto
authors.forename: Fattaneh A
authors.initials: FA
authors.lastname: Tavassoli
mesh_terms: D000328:Adult; D000368:Aged; D001707:Biopsy, Needle; D001943:Breast Neoplasms / Q000473:pathology* / Q000601:surgery; D018270:Carcinoma, Ductal, Breast / Q000473:pathology* / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D012189:Retrospective Studies