Breast Imaging. Beverly Hashimoto

Breast Imaging

• hamartoma

Management

• BI-RADS Assessment Category 2, benign finding

Pearls and Pitfalls

In the literature, hamartomas have also been designated as fibroadenolipomas and adenolipomas. Hamartomas have been reported in patients with a mean age in the late 30s to early 40s. Clinically, the hamartoma may present as a palpable mass, an incidental finding on mammography, or sometimes as tenderness. Rarely a patient presents with nipple inversion or discharge. If the mammogram is performed first, the lesion can be confidently identified if it contains fat. Generally, this mass is not removed. However, in a series in which the tumor was removed, it has been reported to recur in up to 8% of patients.

Suggested Readings

1. Helvie Mak, Adler DD, Rebner M, et al. Breast hamartoma: variable mammographic appearance. Radiology 1989;170:417–421.

2. Hessler C, Schnyder P, Ozzello L. Hamartoma of the breast: diagnostic observations of 16 cases. Radiology 1978;126:95–98.

3. Jackson FL, Lalani Z, Swallow J. Adenolipoma of the breast. J Can Assoc Radiol 1988;39:288–289.

Case 4

Case History

A 73-year-old professional violinist presents for a screening mammogram. She has a history of a soft mass in the upper outer left breast for more than 20 years.

Physical Examination

• left breast: very soft area of asymmetry in the upper outer quadrant

• right breast: normal exam

Mammogram

Mass

• margin: circumscribed

• shape: round

• density: fat-containing

Associated Findings

• completely fatty encapsulated mass in the upper outer quadrant of the left breast (Fig. 4–1)

Figure 4–1. Right MLO mammogram: There is a large, well-defined radiolucent lipoma. The small nodule that projects in the center of the mass is a lymph node located just medial to the lipoma on the CC view.

Ultrasound

Frequency

• 11.5 MHz

Mass

• margin: well defined

• echogenicity: isoechoic

• retrotumoral acoustic appearance: no shadowing

• shape: ellipsoid (Figs. 4–2 and 4–3)

Figure 4–2. Left radial breast sonogram: Combined images of the upper outer quadrant show the margins of the lipoma (arrows). The mass created by the lipoma pushes the thin hyperechoic parenchymal lines (representing lobular regression) superiorly.

Figure 4–3. Left radial breast sonogram: Sonogram is in a normal portion of the same breast as Figure 4–2. This image is intended to demonstrate the normal architecture of the fatty breast parenchyma. F, fatty breast parenchyma; C, Cooper's ligaments; M, chest wall muscle.

Pathology

• lipoma

Management

• BI-RADS Assessment Category 2, benign finding

Pearls and Pitfalls

1. Mammographic fat-containing masses are benign so sonographic examination is generally not necessary. However, occasionally, a patient is referred for sonography for a palpable fatty mass that has not been mammographically characterized. In these cases it is important to be familiar with the sonographic appearance of fatty masses and recommend mammography to confirm the benign identity of the mass.

2. Sonographically, lipomas are generally oval and well defined. They are hypoechoic, isoechoic, hyperechoic, or heterogeneous in echogenicity. In a fatty breast, isoechoic tumors are sometimes difficult to identify. However, this case emphasizes that lipomas do not have the same internal architecture as normal fatty parenchyma. The echogenic lines within the lipoma do not follow a normal pattern of lobular regression.