Do all mucocele-like lesions of the breast require surgery?

The objective of this study is to review the imaging features and percutaneous biopsy findings of mucocele-like lesions (MLLs) of the breast and correlate these with histopathology at surgical excision (SE), where available, to determine whether all MLLs of the breast require surgery for management.A search of two pathology databases was performed to identify 44 patients who had been diagnosed with MLL of the breast and who had corresponding imaging findings available for review. These patients' medical records were reviewed to determine patient age at diagnosis, site of disease/affected breast, symptoms at diagnosis, mammographic and sonographic findings and methods used for histopathologic diagnosis (percutaneous biopsy and/or SE).The mean age of all patients was 56 years (range, 35-76 years). Sixteen patients had MLLs diagnosed by core needle biopsy (CNB) or fine needle aspiration biopsy followed by SE. Eighteen patients had CNB without SE and had clinical and imaging follow-up. Ten patients had MLL diagnosed at SE without prior percutaneous biopsy. In total, 29 patients (66%) had MLLs without atypia, while 10 patients had MLLs associated with atypical ductal hyperplasia (ADH) (23%) and five patients had MLLs associated with ductal carcinoma in situ (DCIS) (11%). Findings were upgraded at SE following the percutaneous biopsy from ADH to DCIS in 19% (3/16) of patients.Surgical excision following the identification of MLL is warranted to exclude coexisting in situ carcinoma in specific situations where CNB detects the presence of associated ADH or where a mass with indistinct or irregular margins is shown by mammography or sonography.