CASE 2 Painless breast mass in a young woman
A 22-year-old woman presents with a 2-month history of breast lump, which is not associated with pain or nipple discharge. On examination, there is a 2 x 2–cm mass in the right breast at 12 o’clock, 2 cm from the nipple, which is mobile, smooth, and nontender on palpation.
Fibroadenoma
In this 22-year-old, the initial imaging of choice is breast ultrasonography. Breast ultrasonography can differentiate a cystic mass from a solid mass, and it does not involve radiation. Right breast targeted ultrasound showed a circumscribed oval homogeneous hypoechoic mass that is wider than tall (FIGURE 2). The patient desired surgical removal, and a pre-lumpectomy core needle biopsy revealed a fibroadenoma.
Art Credit: Images courtesy of Leigh Neumayer, MD, MS, MBA
Fibroadenoma is the most common benign tumor of the breast. It is most often encountered in premenopausal women. Patients present with a painless breast lump, which is smooth and mobile on palpation. Fibroadenoma can be followed expectantly with repeat ultrasound (to assess over time for growth) if it is small and asymptomatic. No further action is needed if it remains stable. If a patient desires surgical excision, a core needle biopsy is usually performed before lumpectomy.
Excisional biopsy or removal of the mass is recommended if the mass is greater than 3 or 4 cm, is symptomatic, or if there is an increase in size that raises clinical concern for phyllodes tumor. Imaging features that are concerning for phyllodes tumors are size greater than 3 cm, indistinct or microlobulated margins, and heterogeneous echo pattern.7,8 In cases in which the imaging features are concerning for phyllodes tumor and a core needle biopsy is not definitive, wide surgical excision is recommended for definitive diagnosis.8
CASE 3 Patient develops breast mass post-surgery
A 45-year-old woman presents with a tender left breast mass that she noticed 2 months after breast reduction surgery. It has been increasing in size since. On clinical examination, a 4 x 4–cm mass is found at the surgical scar site, which is indurated on palpation and tender.
Fat necrosis
In this 45-year-old, the initial test of choice is diagnostic mammography, which showed a somewhat circumscribed area with fat under the palpable marker (FIGURE 3a). Breast ultrasonography was performed for further evaluation, which was inconclusive as the ultrasound showed ill-defined areas of mixed echogenicity (FIGURE 3b). Breast magnetic resonance imaging (MRI) clearly demonstrated fat necrosis in the area of the palpable lump (FIGURE 3c).
Art Credit: Images courtesy of Leigh Neumayer, MD, MS, MBA
Fat necrosis of the breast is an inflammatory process that is seen after breast trauma or surgery. It can present as an incidental mammogram finding or a palpable mass. The patient may give a history of trauma, breast reduction surgery, or breast cancer surgery followed by radiation treatment. On clinical examination, fat necrosis occasionally can present as a firm mass with skin retraction or swelling concerning for cancer. Imaging features are variable depending on the stage of fat necrosis and inflammation.9-11
A mammogram may demonstrate a circumscribed fat-containing mass, an ill-defined mass, asymmetry or calcified oil cyst, and dystrophic calcifications. On ultrasound, fat necrosis can appear as anechoic or hypoechoic or as a complicated cyst or a mixed cystic, solid mass. MRI demonstrates a circumscribed or irregular fat-containing mass, with or without enhancement, and architectural distortion.
When the imaging features are clearly benign—for example, a circumscribed fat-containing mass on mammogram or on ultrasound or, on MRI, marked hypointensity of fat in the center of a circumscribed mass when compared with surrounding fat (keyhole sign)—no further follow-up is needed. When the imaging features are indeterminate, however, a short-interval follow-up can be considered. In cases with irregular fat-containing mass with enhancement, core needle biopsy is indicated to exclude cancer. If the workup remains inconclusive and the level of clinical suspicion is high, surgical excision can be performed for a definitive diagnosis.12
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