Breast hamartoma is a benign lesion that, similar to a visceral hamartoma, comprises elements of its tissue origin growing in a disorganized manner. This includes fat, glandular, and fibrous elements all of which are visible within the lesion. The imaging appearance is pathognomonic, permitting confident radiologic diagnosis. Breast hamartoma generally requires no treatment other than for purposes of cosmesis in cases of large lesions. There is potential for malignant transformation of hamartoma at a rate similar to the normal breast tissue, therefore rapidly growing lesions should be biopsied.