[221] Correlation of Apocrine DCIS on Core Needle Biopsy with Excision

L Huo. The University of Texas M. D. Anderson Cancer Center, Houston, TX

Background: In situ apocrine proliferation in breast encompasses benign apocrine metaplasia, atypical apocrine metaplasia, atypical apocrine proliferation and overt apocrine ductal carcinoma in situ (DCIS). The rarity of apocrine DCIS and its unusual histologic features result in diagnostic difficulty in some cases, especially in core needle biopsy (CNB). To better understand its biological behavior, this study aims to examine aprocrine DCIS and borderline apocrine lesions diagnosed on CNB, and correlate histologic and radiological characteristics with excision outcome and follow-up.
Design: Breast cases coded as atypical aprocrine proliferation or aprocrine DCIS between 1999 and March 2009 were identified in our departmental computer database. Only cases with both CNB and excision reviewed and documented in our system were the subjects of this study, which included 27 apocrine DCIS and 9 apocrine proliferation bordering on or suspicious for DCIS diagnosed on CNB. Radiological characteristics including the size and nature of the target (mass vs. calcifications), and histologic features such as nuclear grade and presence or absence of necrosis on core biopsy were recorded and correlated with final diagnosis on excision and follow-up when appropriate.
Results: Of the 27 cases of apocrine DCIS diagnosed on CNB, 5 (19%) had invasive carcinoma on excision, including 1 microinvasion and 4 invasive ductal carcinoma ranging from 2 to 8 mm. The upgrade on excision did not correlate significantly with nuclear grade or necrosis on CNB, nor the nature of the radiological target (p>0.05, Fisher's exact test). The presence of invasion on excision inversely correlated with radiological size (p=0.02, student t-test) (average size: with no upgrade, 4.6 cm, n=16; with upgrade, 1.8 cm, n=4). Of the 9 cases of atypical apocrine proliferation bordering on or suspicious for DCIC on CNB, 7 cases had the diagnosis of DCIS on excision, and 2 had no residual atypia. Follow-up on a total of 30 cases (range: 10 to 67 months; median: 22 months) revealed one DCIS patient with recurrence of apocrine DCIS at 41 months.
Conclusions: Apocrine DCIS is an uncommon type of in situ carcinoma in breast. The upgrade rate to invasion on excision with a CNB diagnosis of apocrine DCIS is similar to the previously reported rate for DCIS. The observed inverse correlation of lesional size and upgrade on excision suggests that size may not be a reliable parameter in predicting invasion in apocrine DCIS diagnosed on core biopsy. The lack of statistical significance of other parameters needs to be confirmed by a larger cohort.
Category: Breast

Wednesday, March 24, 2010 9:30 AM

Poster Session V # 33, Wednesday Morning


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