Giant cellular blue nevus of the anterior chest wall mimicking metastatic melanoma to the breast: A case report

Background and Objectives: Blue nevi are benign pigmented dermal lesions th at can mimic cutaneous melanoma in appearance. Cellular components may infi ltrate subcutaneous tissue. We present a complex case of cellular blue nevu s (CBN) to demonstrate the ambiguous clinical appearance of these lesions a nd to provide an approach for management of such cases. Methods: We report an extraordinary case of CBN mimicking metastatic melano ma to the breast. A 53-year-old female with an acquired giant blue nevus of the chest wall was found to have two new breast nodules suspicious for mal ignancy on routine mammography. These were biopsied and interpreted as cons istent with metastatic melanoma vs. CBN. The patient underwent complete exc ision of the chest wall nevus and modified radical mastectomy. Results: Pathologic evaluation of the chest wall specimen revealed numerous collections of deeply pigmented melanocytes scattered throughout the breas t parenchyma and embracing ductal structures. No mitoses or nuclear polymor phism were seen. The diagnosis of CBN involving the chest, breast tissue an d axillary lymph nodes was made. Conclusion: Giant blue nevi overlying the breast can develop cellular compo nents that infiltrate subcutaneous and breast tissue resulting in the appea rance of breast nodules on mammography. A generous excision biopsy inclusiv e of the overlying nevus and breast component may be required to establish the dignity of the lesion. (C) 2000 Wiley-Liss, Inc.