[245] The Diagnostic Utility of the “Minimal Carcinoma (MC) Triple Stain” in Breast Carcinomas.

Dara S Ross, Yi-Fang Liu, Jennifer Pipa, Sandra J Shin. Weill Cornell Medical College, New York, NY

Background: Minimal breast carcinoma (≤ 3 mm in size) is an increasingly common and diagnostically challenging lesion encountered in daily practice. Accurate classification (i.e. lobular vs. ductal; in-situ vs. invasive) directly impacts subsequent clinical management, especially when the focus is near a surgical margin or present in a needle core biopsy (NCB). Immunohistochemistry enables pathologists to fully characterize such lesions however in some instances the number of immunostains necessary exceeds the amount of lesional tissue available for study. We assessed the diagnostic utility of a combined immunostain of 3 commonly employed antibodies (CK7, p63 and E-cadherin) to evaluate these problematic lesions.
Design: 148 specimens containing minimal (≤ 3 mm in size) breast carcinoma were identified. In each case, the MC Triple Stain which consisted of Vector Blue (Vector laboratories, Inc.), DAB and Refine Red (Leica Microsystems) chromogens utilized for p63 (clone 4A4, Biogenex), E-cadherin (clone HECD-1, Invitrogen), and CK7 (clone OV-TL 12/30, Dako), respectively, was prepared with a parallel H&E stained slide. Observations of staining characteristics in MC were recorded.
Results: The MC Triple Stain demonstrated diagnostic staining in all but one case studied, specifically, 79 invasive ductal carcinomas (43 excisional biopsy [EXBX], 36 NCB), 68 invasive lobular carcinomas (ILC) (38 EXBX, 30 NCB), 49 ductal carcinoma in-situ (36 EXBX, 13 NCB), and 37 lobular carcinoma in-situ (27 EXBX, 10 NCB). See Figure 1: ILC surrounding a benign duct.

In one ILC, the MC Triple Stain stained only the surrounding breast tissue (appropriately) and not the MC focus. MC in 32 of 81 EXBX (40%) was located ≤ 2 mm from the inked surgical margin; all were fully diagnostic by the MC Triple Stain despite morphologic distortion due to concomitant cautery artifact and tissue disruption.
Conclusions: The MC Triple Stain is diagnostically useful in fully characterizing breast carcinoma of minimal size. This combination immunostain offers an accurate and tissue-conserving method to fully characterize and diagnose small, morphologically problematic foci of breast carcinoma while ideally leaving more tissue for adjunctive studies necessary for further clinical management and treatment in these patients.
Category: Breast

Wednesday, March 2, 2011 1:00 PM

Poster Session VI # 11, Wednesday Afternoon


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