[530] Value of P63 and Podoplanin (D2-40) Immunoreactivity in the Distinction between Primary Cutaneous Tumors and Carcinomas Metastatic to the Skin: A Clinicopathologic and Immunohistochemical Study of 79 Cases

P Ortega, D Stockman, S Suster, JA Plaza. Medical College of Wisconsin, Milwaukee, WI

Background: The distinction of metastatic carcinomas to the skin from poorly differentiated primary cutaneous carcinomas and sometimes primary benign adnexal tumors can pose a significant diagnostic challenge. The purpose of this study was to evaluate the role of P63 and podoplanin (D2-40) immunoreactivity for separating primary skin tumors versus cutaneous metastases of carcinomas from internal organs.
Design: Thirty seven primary tumors and 42 cutaneous metastatic carcinomas were evaluated. The 37 primary cutaneous tumors included 14 cases of benign adnexal tumors, 9 malignant skin adnexal neoplasms, and 14 primary squamous and basal cell carcinomas. The 42 metastatic carcinomas all corresponded to metastases from internal organs in patients with a well-documented history of a primary tumor at another location.
Results: We found variable positivity with podoplanin in all primary cutaneous neoplasms including spiradenoma (6/6), hidradenoma (2/4), cylindroma (3/3), desmoplastic trichilemmoma (1/1), poorly-differentiated squamous cell carcinoma (4/4), sebaceous carcinoma (1/1), basal cell carcinoma (4/10), trichilemmal carcinoma (2/2), eccrine carcinoma (3/3), microcystic adnexal carcinoma (1/1), adnexal carcinoma NOS (1/1), and porocarcinoma (1/1). In contrast, all visceral metastatic carcinomas were negative (0/42) for podoplanin. In regards to P63, all cases of primary cutaneous tumors were positive for P63 (37/37); in contrast, all cutaneous metastatic visceral carcinomas were negative (0/42). Sensitivity, specificity, and positive and negative predictive value of podoplanin and P63 immunoreactivity to separate primary skin neoplasms from metastatic carcinomas was 78.4%, 100.0%, 100.0%, and 84.0% for podoplanin, respectively, and 100.0%, 100.0%, 100.0%, and 100.0% for p63, respectively.
Conclusions: The differences in p63 and podoplanin immunohistochemical expression between primary skin tumors and metastatic carcinomas to the skin were statistically significant (p<0, 0001). The results of our study suggest that the combined expression of P63 and podoplanin are a useful adjunct for the diagnosis of skin tumors in the clinical setting of a questionable metastasis and may be relatively specific for distinguishing primary skin tumors from metastatic carcinomas to the skin.
Category: Dermatopathology

Wednesday, March 24, 2010 1:00 PM

Poster Session VI # 94, Wednesday Afternoon

 

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