Radiologic findings of metastatic malignant melanoma of the breast: Mammographic, sonographic, dynamic contrast-enhanced breast MRI, and 18F-FDG PET-CT features

Metastatic involvement of the breast from an extra-mammary tumor is rare. However, when a patient with a known primary malignancy complains of a palpable breast mass, both the primary breast cancer and the metastatic lesion must be considered as a differential diagnosis. Melanoma is one of the tumors that commonly metastasizes to the breast, but the characteristic imaging features are not well known. Therefore, an understanding of the characteristic image findings for melanoma would be advantageous in differentiating a breast mass in patients with a history of melanoma. A 73-year-old woman with a history of recurring melanoma in the nasal cavity presented with a palpable mass in the left breast. She had undergone various imaging studies, which revealed two masses in the left breast and an enlarged right intramammary lymph node. The patient underwent lumpectomy of masses in the left breast for tissue confirmation, and pathologic examination revealed metastatic melanoma. Melanoma exhibits typical signal intensity on MRI and commonly metastasizes to the breast. Therefore, it is important to be aware of the characteristic imaging findings for metastatic melanoma, particularly when a melanoma patient presents with a breast lump.