[146] Minimally Invasive Paget Disease of Breast: An Under-Recognized Entity in the Breast.

Xiuzhen Duan, Nour E Sneige, Ashley E Gullett, Victor G Prieto, Erika Resetkova, Constance T Albarracin. University of Texas Health Science Center, Houston; MD Anderson Cancer Center, Houston, TX

Background: Mammary Paget disease (MPD) is an intraepidermal adenocarcinoma. In contrast to extramammary Paget disease (EMPD), invasion of MPD cells into the dermis has not been reported except for a case illustrated in Rosen's textbook on Breast Pathology. This retrospective study was designed to evaluate for invasion in MPD and to characterize its clinicopathologic features.
Design: We identified 595 MPD between 1985 and 2010 with available slides from 146 patients. There were six cases of MPD with minimal invasion (invMPD); verified by pathologists from three subspecialties (breast, gynecologic, and dermatology). The depth of invasion was measured from the dermal-epidermal junction to the focus of deepest invasion. Also evaluated were the extent of intraepidermal MPD and histologic features of the underlying breast carcinoma.
Results: InvMPD was associated with invasive ductal carcinoma (IDC, 2 cases), ductal carcinoma in situ (DCIS) with microinvasion (1), and DCIS alone (2 extensive and 1 focal). The depth of invasion ranged from 0.06 to 0.58 mm and the horizontal spread from 0.06 to 0.65 mm. Immunohistochemical studies demonstrated that the underlying breast tumors were positive for ER, PR, and HER2 in one IDC and one DCIS. These markers were all negative in the other IDC. The microinvasion case was ER-PR-HER2+ and another DCIS was ER+PR-HER2+. Information of these markers in one DCIS was not available. Two of the six cases had lymph node metastasis and isolated tumor cells, respectively. One patient died of heart attack at two years after diagnosis and the remaining patients were alive without disease at their last follow-up visit (8 months to 8 years).
Conclusions: We provide the first series of MPD with invasion into the dermis. Our results indicate that invMPD can present in association with either invasive or in situ breast cancer with varying expression of ER/PR and HER2. At least two of six cases had some lymph node involvement however, analysis of even larger series may be necessary to determine the possible prognostic significance of this variant.
Category: Breast

Monday, February 28, 2011 1:00 PM

Poster Session II # 59, Monday Afternoon


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