[481] Oncofetal Protein IMP3, a Diagnostic Biomarker To Distinguish Microcystic Adnexal Carcinoma from Syringoma

Kristine Cornejo, April Deng. University of Massachusetts Medical School, Worcester, MA

Background: An accurate diagnosis between microcystic adnexal carcinoma (MAC) and syringoma is essential for patient management. The diagnosis of MAC, especially in superficial biopsies can present a diagnostic challenge. IMP3 is an oncofetal protein associated with aggressive and advanced tumors and is specifically expressed in malignant tumors but not found in benign tissues. The aim of this study was to investigate the expression of IMP3 in MAC and syringoma and determine whether it can serve as a diagnostic biomarker for MAC.
Design: A total of 47cases (excision, n=19; biopsy, n=28), including 12 MACs and 35 syringomas were obtained from the surgical pathology files of a tertiary Medical Center between 2002 and 2011. The diagnoses of all the cases were confirmed by at least two pathologists.
Results: A positive immunohistochemical stain for IMP3 (cytoplasmic staining) was not identified in any of the syringoma cases (0%) but stained positive in 8 of 12 cases (67%) (P<0.001). IMP3 positivity was detected in >50% of tumor cells in 5 (63%) cases and <50% of tumor cells in 3 (37%) cases. The sensitivity of IMP3 for the detection of MAC was 67% and the specificity was 100%.
Conclusions: Our findings indicate that IMP3 is a fairly sensitive and highly specific positive biomarker for MAC. IMP3 is expressed in MAC but not in syringoma, which suggests it may play an important role in the pathogenesis of MAC as it has been shown to play a role in cell proliferation, invasion and migration. The expression of IMP3 in tumor cells can increase the level of confidence in establishing a definitive malignant diagnosis of MAC from syringoma.
Category: Dermatopathology

Tuesday, March 20, 2012 9:30 AM

Poster Session III # 112, Tuesday Morning

 

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