title: The mucinous variant of columnar cell lesions.
abstract: OBJECTIVE
  Mucin-producing columnar cell lesions (CCL) are a rare, new entity in the breast. The aim of this study was to describe the incidence and follow-up of mucinous CCLs.
  
  
  RESULTS
  Of 4164 breast core needle biopsies (CNBs), 291 showed a CCL and 21 atypical ductal hyperplasia (ADH) originating in a CCL (ADH-CCL). Mucin production was present in 17 of 291 (5.8%) CCLs and three of 21 (14.3%) ADH-CCLs, together concerning 0.5% of all CNBs. The most common mucinous CCL pattern was a columnar cell change without atypia, and almost all were detected with microcalcifications as an abnormality at mammography. During a median follow-up of 3.1 years, no invasive carcinoma or ductal carcinoma in situ was detected. MUC2 was expressed in intraluminal mucin in 12 of 15 (80%) mucinous CCLs, and showed cytoplasmic expression in five of 15 (33%) mucinous CCLs seen in CNBs. Moreover, mucinous CCLs were significantly more common in association with 46 mucinous carcinomas than in 46 ductal carcinomas (28% versus 9%).
  
  
  CONCLUSIONS
  Mucinous CCLs are rare lesions, with an incidence of about 0.5% in breast CNBs, usually presenting with microcalcifications. Although these lesions might play a role in the mucinous progression spectrum, the short-term risk of progression to more advanced lesions seems to be low.
authors.affiliation: Department of Pathology, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Anoek H J
authors.initials: AH
authors.lastname: Verschuur-Maes
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Van Diest
mesh_terms: D002288:Adenocarcinoma, Mucinous / Q000175:diagnosis / Q000378:metabolism* / Q000473:pathology*; D000328:Adult; D000368:Aged; D001707:Biopsy, Needle; D001943:Breast Neoplasms / Q000175:diagnosis / Q000378:metabolism* / Q000473:pathology*; D002285:Carcinoma, Intraductal, Noninfiltrating / Q000175:diagnosis / Q000378:metabolism / Q000473:pathology; D002291:Carcinoma, Papillary / Q000175:diagnosis / Q000378:metabolism / Q000473:pathology; D048430:Cell Shape; D003937:Diagnosis, Differential; D018450:Disease Progression; D005260:Female; D006801:Humans; D006965:Hyperplasia / Q000175:diagnosis / Q000378:metabolism / Q000473:pathology; D008875:Middle Aged; D055262:Mucin-2 / Q000378:metabolism*; D012189:Retrospective Studies
chemical_list: C524625:MUC2 protein, human; D055262:Mucin-2