Clinicopathologic Correlation of Cutaneous Metastases

Abstract

Cutaneous metastases from internal organ malignancies or soft tissue sarcomas are uncommon findings in clinical dermatology and dermatopathology. However, with an increasing incidence of cancers, dermatologists and dermatopathologists are more likely to encounter or even be the first physicians to discover the malignancy. Clinically, the lesions do not have a uniformly characteristic appearance. Histologic features vary depending on the type of originating malignancy and, in some instances, require differentiation from a primary cutaneous tumor. Several series^1-4 have reported the clinical appearances and histologic changes of cutaneous metastasis. The studies provide detailed and excellent illustrations of the histologic features based on the organs of origin^4-6 and histologic types.² However, most studies have included malignant melanomas or lymphomas^3-5 and direct extension and local recurrences.⁷ This study summarizes the clinical, histologic, and immunohistochemical findings in biopsy-proven cutaneous metastases observed at the Fox Chase Cancer Center between January 1, 1990, and December 31, 2005. The cases selected were restricted to metastases from internal organ malignancies and soft tissue sarcomas, with exclusion of melanomas, hematologic malignancies, direct tumor extension, and local recurrences. We emphasize unusual clinical presentations, clinical outcomes in patients, and the practicality of recognizing cutaneous metastases and their origins in a daily dermatopathology practice, where a detailed clinical history is often not available, and we suggest an immunohistochemical panel that may facilitate differentiation from skin adnexal tumors.