[137] Immunohistochemical Characterization of Cystic Hypersecretory Carcinoma

Timothy M D'Alfonso, Yi-Fang Liu, Sandra J Shin. Weill Cornell Medical College, New York, NY

Background: Cystic Hypersecretory Carcinoma (CHC) is a variant of DCIS uniquely containing luminal secretion resembling thyroidal colloid. CHC is thought to behave in an indolent manner, but has the potential to give rise to invasive carcinoma, which is typically poorly-differentiated. Despite its characterization as a clinicopathologic entity over two decades ago, the immunohistochemical (IHC) profile of CHC remains unclear. We set out to better define the IHC features of this uncommon lesion.
Design: 10 cases of CHC were identified from our files. In each case, IHC stains were performed using the Bond Max Autostainer (Leica) with appropriate controls and resulting slides were reviewed by two breast pathologists.
Results: All 10 cases were biopsies (9 excisional; 1 needle core) of women averaging 63 years in age (range: 47-79). The clinical/radiographic presentation was a mass (5/10), calcifications (3/10), bloody nipple discharge (1/10), and unknown (1/10). No cases showed concurrent invasive carcinoma. The microscopic size of CHC ranged from 0.2 to 2.7 cm (mean, 0.9). The architecture was predominantly micropapillary (9/10; 90%) whereas the nuclear grade was either intermediate (5/10; 50%) or high (5/10; 50%). Calcifications were present in CHC in 7/10 (70%) cases. One case was associated with pregnancy-like hyperplasia. CHC arose in a background of cystic hypersecretory change/hyperplasia (CHChange/CHH) and atypical cystic hypersecretory hyperplasia (ACHH) in most cases (7/10; 70%) while the remaining 3 cases had only co-existing CHChange. Luminal secretions were present in all cases and characteristically exhibited retraction, “pock marks,” and “Venetian blinds.” CHC was ER+/PR+ in 4/10; ER+/PR- in 4/10 and ER-/PR- in the remaining 2/10. All were HER-2 negative. Androgen receptor was positive in 3/10 (30%) cases. Myoepithelial stains p63, smooth muscle myosin (SMM), and CK5 showed circumferential staining in 9/10 (90%) cases while 1 case was negative for p63, SMM, and CK5 in both CHC and adjacent CHChange. CK5 showed variable staining in 3/10 (30%) cases. Basal markers EGFR, CK14, and CK5 were negative in all cases with the exception of 2 cases, each positive for EGFR or CK5.
Conclusions: CHC is a distinct variant of DCIS that typically arises in a background of CHChange/CHH/ACHH and exhibits micropapillary architecture, intermediate to high-grade nuclei, and luminal colloid-like secretion. CHC is typically ER/PR positive and HER-2 negative. Basal markers are consistently non-reactive. Negative or discontinuous reactivity with myoepithelial markers may be seen, despite its in-situ nature.
Category: Breast

Wednesday, March 6, 2013 1:00 PM

Poster Session VI # 3, Wednesday Afternoon

 

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