OMICS Journal of Radiology
Open Access

Hamartoma is a pseudotumor lesion of the breast. Benign and rare, it can appear at any age, but occurs preferentially in women over the age of 35 [1].

It is usually asymptomatic and is most often discovered incidentally. Histologically, the hamartoma contains the main components of the normal mammary gland, namely adipose, glandular and fibrous tissue. Diagnosis is mainly based on echo mammography. It may be discovered incidentally on MRI.

On mammography, the appearance of the hamartoma depends on the proportion of these constituents. It is most often a round or oval, well-limited mass of variable size, forming the image of a “breast within a breast” Figure 1A. On ultrasound, a heterogeneous, compressible echogenic lesion is found, isolated from the breast tissue by a pseudo-capsule, with no attenuation cone or posterior enhancement of the echoes Figure 1B [1,2].

Figure 1A: Oblique mammography of the left breast, showing a fat density mass in the upper medial quadrant reminiscent of normal breast tissue: this is the “breast in the breast” image.

Figure 1B: Ultrasonography showing an oval, echogenic, heterogeneous formation, limited by a pseudo-capsule, pushing the glandular tissue backward.

They have an MRI appearance that fits well with their schematic definition of a normal breast island in the breast: a well-limited area whose contents have the appearance of the normal breast matrix (with its islands of fat), including physiological enhancement due to hormonal impregnation Figure 2 [3].

Figure 2: Axial slice of breast MRI showing a well-limited, encapsulated, oval mass in the upper medial quadrant with a signal identical to the normal mammary gland giving a “breast in the breast” appearance A-T2-weighted B-after injection of gadolinium.

The hamartoma is often respected, except in cases of malignant transformation, when its removal is indicated.