[524] Syringoid Eccrine Carcinoma: A Clinicopathologic and Immunohistochemical Study of 7 Cases.

Michael Sidiropoulos, Shachar Sade, Ayman Al Habeeb, Danny Ghazarian. University of Toronto, ON, Canada; Sunnybrook Health Sciences Centre, Toronto, ON, Canada; University Health Network, Toronto, ON, Canada

Background: Syringoid eccrine carcinoma (SEC) is an extremely rare malignant adnexal tumor of eccrine origin, often with variable presentations. We report seven cases of SEC, highlighting clinicopathological characteristics and immunohistochemical (IHC) features of these tumors.
Design: SEC cases accessioned between 2001-2010 were retrieved from the archives of the University Health Network. Seven cases were reviewed by three dermatopathologists and the IHC profile was examined using antibodies against: cytokeratin (CK) 5/6, CK7, CK14, CK20, low-molecular weight keratin (LMWK), high-molecular weight keratin (HMWK), epithelial membrane antigen (EMA), monoclonal carcinoembryonic antigen (mCEA), p63, estrogen receptor (ER), progesterone receptor (PR), androgen receptor (AR), S-100 and Ber-EP4.
Results: The cases occurred in three males and four females, ranging in age from 31 to 87 years (mean 58.9). Two of the lesions were from the head, three from the trunk and two from the upper extremities. All seven lesions were composed of an atypical infiltrative mass with syringoma-like tadpole morphology with ductular differentiation and prominent desmoplasia. Three cases demonstrated perineural invasion and two had positive lymph node metastases. Immunostaining was variable. Immunohistochemistry positivity was as follows: 6/7 cases were positive for CK5/6, CK7 (5/7), CK14 (3/4), CK20 (0/3), HMWK (2/4), LMWK (4/5), EMA (4/6), mCEA (4/5), p63 (3/5), ER (2/5), PR (1/4), AR (0/4), S-100 (2/5), and Ber-EP4 (3/3).
Conclusions: We believe the variability in both the histopathologic features and immunostaining seen in SECs is from this tumours ability to variably differentiate along multiple routes, including sweat secretory and/or ductal differentiation. Similar to other adnexal tumors, the role of myoepithelial cells within SECs is still controversial and may further contribute to the complexity and variability seen in these lesions. Future studies with new markers and discriminatory keratins may help elucidate SECs origin and differentiation.
Category: Dermatopathology

Monday, February 28, 2011 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 71, Monday Morning


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