title: Mammary mucinous lesions: congeners, prevalence and important pathological associations.
abstract: A retrospective histopathological study was undertaken to determine the prevalence of mucin filled ducts and their associated mucinous proliferation in 962 breast cancers and 335 benign lesions. A total of 38 (3%) cases with mucin filled ducts was identified and 27 (2%) of these showed mucin extravasation into the adjacent stroma, changes characteristic of mucocoele-like lesions. This constitutes the largest series reported to date. Of the mucocoele-like lesions 12 were prototypic screen-detected cases: 11 of which were mammographically detected on account of suspicious microcalcification and eight cases (67%) exhibited mucinous atypical ductal hyperplasia without overt malignancy. A further 12 mucocoele-like lesions were incidental findings in screen-detected (11) and symptomatic (one) cancers, the majority of which were invasive ductal carcinomas of no special type. In six of these cases (50%), mucinous atypical ductal hyperplasia or ductal carcinoma in situ was present. Thirty mucinous carcinomas constituted 3% of all cancers and three cases had associated mucocoele-like lesions. Mucinous atypical ductal hyperplasia or ductal carcinoma in situ was also associated with 11 cases of mucinous carcinoma. In six mucinous carcinomas, amorphous microcalcification with a similar appearance to that of benign mucocoele-like lesions was identified in the mucin, suggesting a possible link between the two lesions. Mucin-filled ducts or mucocoele-like lesions were almost twice as frequent in screen-detected as in symptomatic lesions. The presence of mucinous atypical ductal hyperplasia in screen-detected mucocoele-like lesions, a decade earlier than the peak of mucinous carcinoma, is a possible risk factor for subsequent invasive malignancy. Mucin-filled ducts, mucocoele-like lesions, mucinous atypical ductal hyperplasia or ductal carcinoma in situ and mucinous carcinoma may represent different stages of the same disease process. Our findings suggest that patients with mucin-filled ducts of mucocoele-like lesions merit close follow-up.
authors.affiliation: Regional Breast Pathology Unit, University of Bristol, Southmead Hospital, UK.
authors.forename: C N
authors.initials: CN
authors.lastname: Chinyama
authors.forename: J D
authors.initials: JD
authors.lastname: Davies
mesh_terms: D002288:Adenocarcinoma, Mucinous / Q000473:pathology*; D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000473:pathology*; D002114:Calcinosis / Q000473:pathology; D002278:Carcinoma in Situ / Q000473:pathology; D018270:Carcinoma, Ductal, Breast / Q000473:pathology; D005348:Fibrocystic Breast Disease / Q000473:pathology*; D006801:Humans; D006965:Hyperplasia; D008875:Middle Aged; D009078:Mucocele / Q000473:pathology*; D012189:Retrospective Studies