Primary Noncutaneous Malignant Melanoma of the Breast.

Primary noncutaneous breast melanoma without an apparent skin primary lesion is uncommon. Its pathogenesis is debated with some authors believing that it is a metastatic disease from an undiscovered primary or a primary that has since completely regressed but it may be a true primary tumor arising from ectopic melanocytes. We present a case of a V600E BRAF mutation-positive primary noncutaneous breast melanoma diagnosed at an early stage in a screening mammogram as a solitary breast lesion without nodal involvement. Considerations of treatment of this rare disease are discussed.