[242] Carcinoma In Situ Involving Sclerosing Adenosis: Diagnostic Pearls To Aid the Practicing Pathologist.

Dana Richards, Alberto A Ayala, Lavinia P Middleton. UT MD Anderson Cancer Center, Houston, TX; Methodist Hospital, Houston, TX

Background: Involvement of pre-existing benign lesions by ductal carcinoma in situ (DCIS) or lobular neoplasia (LN) can present difficult diagnostic challenges, and can easily cause misdiagnosis and mismanagement when presented on core biopsy specimens. Our objective was to gather the largest case series of DCIS and LN involving sclerosing adenosis (SA), and to report the characteristic features of these lesions, in order to provide histologic criteria for the diagnostic pathologist.
Design: Our database was searched (1999 to 2010) for core biopsy material diagnosed as carcinoma in situ involving adenosis. Glass slides and pathology reports were reviewed. Cases were studied for salient features, and clinical follow-up was obtained.
Results: 31 cases of DCIS or LN involving SA were obtained (12 cases of DCIS, 19 cases of LN including LCIS and ALH).
Histomorphologic features commonly seen with DCIS or LN involving SA included lobulocentric architecture (31/31, 100%), myoepithelial cells visible by H&E at least focally (31/31, 100%), and separate areas of SA uninvolved by neoplasia (29/31, 93.5%). Features that were sometimes seen included hyaline basement membranes surrounding the lesion (14/31, 45.2%), DCIS/LN apart from the area of involvement by SA (16/31, 51.6%), and calcifications associated with DCIS/LN/SA (12/31, 38.7%). Uncommonly seen features included desmoplasia (6/31, 19.4%), dense inflammation (4/31, 12.9%), and single epithelial cells enveloped by flattened myoepithelial cells (6/31, 19.4%).
Of the ten cases of DCIS with known follow-up, four showed DCIS involving either SA or a complex SA on excision (4/10, 40%), four had only DCIS (4/10, 40%), one had DCIS with a small 1.8 mm focus of predominantly tubular carcinoma (1/10, 10%), and one showed invasive ductal carcinoma (IDC) on excision (1/10, 10%). The latter case of IDC occurred in a patient who had a delay of three years from diagnosis to surgical resection. Of the eight cases of LN with surgical follow-up, seven had LCIS (7/8, 87.5%), and one showed fibroadenoma and SA with no residual LN in the excised specimen (1/8, 12.5%). No invasive carcinoma was identified in any of the resections for LN involving SA.
Conclusions: Lobular lesions involving SA were more common than ductal lesions. DCIS involving adenosis were best diagnosed by the low-power appearance. Immunohistochemical stains for myoepithelial cells were utilized only in particularly difficult cases. The presence of desmoplasia does not preclude the diagnosis of carcinoma in situ involving adenosis.
Category: Breast

Monday, February 28, 2011 1:00 PM

Poster Session II # 58, Monday Afternoon


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