Diagnostic Delays in Metastatic Amelanotic Melanoma Presenting as Breast Pain

BACKGROUND Breast metastases from melanoma are rare. Amelanotic melanoma is difficult to diagnose, as primary lesions not only lack the pigment typical of melanoma, but also lack other features associated with these tumors, including asymmetry, irregular borders, and color variegation. CASE REPORT A 58-year-old woman presented with an enlarging mass on her left breast, a finding confirmed by physical examination. Mammography showed a 10-cm breast mass of category 4 according to the Breast Imaging Reporting and Data System (BI-RADS). Staging computed tomography (CT) showed widely scattered metastatic sites in the brain, lungs, mediastinum, and adrenal glands. A biopsy of the mass in her left breast was non-diagnostic due to extensive necrosis. Because of severe pain, simple left breast mastectomy was performed. Tissue from the mastectomy revealed a diagnosis of amelanotic malignant melanoma. CONCLUSIONS Diagnosing amelanotic melanoma is difficult without tissue biopsy as these tumors lack the typical features of melanoma and can mimic other dermatologic diseases. This frequently results in a significant delay in diagnosing amelanotic melanoma, with patients often presenting with advanced stage disease having poor prognosis.