Breast within a Breast appearance: Breast hamartoma

Breast hamartomas are rare benign breast tumors well defined with a slow development. They are also known as fibroadenolipomas or or adenolipoma (1). They are generally encountered in middle-aged women over the age of 35, with an overall incidence of 4.8% benign breast lesions; (2) However, the incidence is believed to have increased due to breast cancer screening programs (3).

In terms of pathology, all hamartoma constituents are normal components of normal breast tissue. The terminology Fibroadenolipoma refers to a benign process of fibrous, glandular, and fatty tissue development enclosed by a thin capsule of connective tissue,

Because of the considerable variation in adipose and fibrous tissue components, the presentations of hamartomas in the Ultrasound vary greatly. They usually appear as firm, well-defined circular shapes parallel to the skin plane with heterogeneous echo structure with hypoechoic and hyperechoic intermingled regions, indicating the presence of epithelial fibrous and adipose tissues (4).

On mammography, hamartomas are typically observed as oval or circular forms that are heterogeneous, with radio-opaque and radiotransparent regions indicating the presence of tissues with varying densities. A thin radio-opaque pseudocapsule separates them from the adjacent breast tissue (5).