[206] Benign Mucocele like Lesions of the Breast: Revisited

S Jaffer, C Nagi, IJ Bleiweiss. The Mount Sinai Medical Center, New York, NY

Background: Mucocele like lesions (MLL) of the breast are ruptured cystically dilated mucin producing ducts that discharge their contents into the stroma.They constitute a spectrum of changes from benign to atypical to malignant. The current management of these lesions diagnosed on core biopsy (CB) is excision. The goal of our study was to evaluate the necessity of this practice for benign MLL (BMLL).
Design: Retrospective review of the pathology database from 1/1/2000 to 6/1/2008 identified 61 cases, with follow up information available in 50. Clinical, radiologic and pathologic information was correlated. CBs were reviewed to confirm the diagnosis of BMLL and exclude atypical or malignant changes. Excisions were also reviewed to determine final diagnosis and verify previous CB changes.
Results: 45 patients underwent surgery while 5 patients were followed >1year and are stable. Patients' age ranged from 44 to 76 years (mean=54.6). Method of diagnosis was stereotactic CB for calcifications (Ca++) in 44 and ultrasound for masses in 6. Ca++ on mammogram were clustered(35 cases), new(3), coarse(2) linear(1), granular(1), pleomorphic(1) and suspicious(1). The size of the BMLL on CB ranged from incipient lesions (<0.1 cm) to 0.6cm. Most excisions had no residual MLL (36/45=80%). In 7 cases (15.6%) atypical duct hyperplasia (ADH) was present, 4 with residual MLL. In 1 of these cases, the residual MLL showed a continuum from florid duct hyperplasia to ADH at the CB site. The other 6 cases showed ADH adjacent to but not at the CB site. The size of the BMLL ranged from incipient to 0.5cm. Ca++ were identified in the BMLL in 6 cases. In the 7th case, Ca++ were identified only in fibrocystic changes while the BMLL was an incidental finding (0.1cm). There was only 1 case of DCIS in which the Ca++ were suspicious and widespread. Review of CB showed BMLL (0.3cm) and atypical lobular hyperplasia. Excison showed residual MLL with ADH and LCIS admixed with focal low grade DCIS.
Conclusions: Clinically, BMLL ocurr in older women. In this series, the largest of its kind, the upstage rate of BMLL diagnosed on CB was 17.8%. Most BMLL diagnosed on CB lacked a residual component on excision. With the exception of the DCIS case, radiologic features were not predictive of atypia. The size of the BMLL on CB did not affect outcome as both incipient and incidental lesions were associated with ADH. In most cases, the ADH was adjacent to but not at the CB site. Thus, due to associated ADH, sampling reasons, and intralesional heterogeneity, we continue to recommend excision of BMLL diagnosed on CB.
Category: Breast

Monday, March 9, 2009 8:00 AM

Platform Session: Section B, Monday Morning