Marina I. Feldman MD,MBA, Abstract Co-Author: Nothing to Disclose

Megan Sullivan, Abstract Co-Author: Nothing to Disclose

Ellen Bachman Mendelson MD, Abstract Co-Author: Scientific Advisory Board, Hologic, Inc Research support, Siemens AG Speakers Bureau, Siemens AG Medical Advisory Board, Quantason, LLC Consultant, Quantason, LLC Speakers Bureau, SuperSonic Imagine Research support, SuperSonic Imagine Medical Advisory Board, Toshiba Corporation

Lilian Wang MD, Presenter: Nothing to Disclose

Mucocele-like lesions (MLL) of the breast are uncommon. Originally described as a benign entity, MLLs have been reported to be associated with atypical ductal hyperplasia (ADH), ductal carcinoma in situ (DCIS), invasive ductal carcinoma (IDC), and low-grade mucinous carcinoma, and thus represent a spectrum of lesions ranging from benign to malignant. Our goal was to review the imaging features and analyze the upgrade rate of MLL with ADH, DCIS, IDC or mucinous carcinoma in order to establish management guidelines based on biopsy results.

Our breast pathology database from the last 10 years was retrospectively reviewed to identify patients with histologic diagnoses that included mucin-containing lesions. Mammographic, sonographic and MRI exams, if performed, were reviewed and correlated with histologic diagnoses. Clinical presentation of each patient (e.g. masses, microcalcifications, etc.) prior to diagnosis and their management following the core biopsy were noted. Where the lesion was surgically excised, final surgical pathology was correlated to assess an upgrade rate, if any, from biopsy to final excisional diagnosis. Upgraded cases were again correlated with imaging to establish concordance at each step. Further, follow-up imaging evaluations to date were reviewed for subsequent breast disease or recurrent MLL.

Our 28,301 core needle biopsies performed the last 10 years yielded 232 mucin-containing lesions. 28 were MLL-only, 22 were MLL with atypia, 3 were MLL with DCIS, for a total of 53 MLL and 148 IDC with mucinous features. IDC with mucinous features were further sub-categorized into mucinous carcinomas and IDC. 92% of MLL-only lesions and 100% of the MLL with atypia lesions presented with calcifications. Of the excised MLL-only lesions, none upgraded to ADH and DCIS. Of the excised MLL with atypia lesions, 40% upgraded at excision.

Surgical excision of MLL when associated with atypia is recommended due to high rate of upgrade. However, diagnosis of MLL alone on core biopsy is likely reliable and may not require excision.

Our data demonstrate that MLL is benign when present alone. Association with atypia is highly suggestive of upgrade to malignancy on excision. Excision of MLL-only lesions is therefore unnecessary.

Feldman, M, Sullivan, M, Mendelson, E, Wang, L, Mucocele-like Lesions and Biopsy-driven Management: Excision Is Not Always Needed.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11013755.html