Bilateral nipple inversion is a benign condition, in which the nipples are completely beneath the level of the skin (see the figures). The nipples may evert on pressure and then resume the inverted position. This condition may interfere with lactation but is not otherwise of clinical concern and is often long standing or congenital. Benign inversion may also manifest as a slitlike area of the nipple pulled in. Nipple inversion is better seen on digital mammography than on film-screen mammography because tissue equalization algorithms allow better visualization of the skin and nipples.

A benign inverted nipple must be differentiated from a pathologically retracted nipple. The terms retraction and inversion are used interchangeably, which may cause confusion. When nipple retraction is new, it may be caused by duct ectasia, periductal mastitis, or malignancy. Cancer that develops in the retroareolar breast is typically invasive ductal carcinoma or invasive lobular carcinoma and, particularly if it develops close to the nipple, may cause the nipple to pull in, or retract. A pathologically retracted nipple does not evert on clinical examination, as a benign inverted nipple does. Paget disease of the nipple manifests as an erythematous area on the nipple-areolar complex and may cause nipple retraction. It has an association with ductal carcinoma in situ in the subareolar ducts. Inflammatory cancer of the breast can manifest with nipple retraction, but additional findings are present, with larger areas of thick, erythematous skin and peau d’orange.

The patient shown here had long-standing bilateral nipple inversion, and the mammographic appearance was stable. No further work-up is needed.

CASE 42

History: A 60-year-old woman presents for routine mammography. She has a personal history of breast cancer, which was occult on mammography and seen only on ultrasound. She was treated with breast conservation therapy. Because of her history, she requests ultrasound of both breasts annually, in addition to mammography.

1. What should be included in the differential diagnosis of the mammogram and ultrasound images shown? (Choose all that apply.)

A. Calcified fibroadenoma

B. Breast conservation therapy with calcified fat necrosis

C. Breast conservation therapy with calcification suspicious for recurrence

D. Calcification in the right breast related to radiation therapy

2. If you find a dense shadowing mass on ultrasound, how should you proceed?

A. All dense shadowing masses are suspicious, and biopsy should be performed.

B. Correlate the ultrasound finding with the mammogram.

C. Further work-up should be based on clinical examination.

D. Evaluate further with MRI, looking for abnormal enhancement.

3. What is the BI-RADS (Breast Imaging Reporting and Data System) for this mammogram and ultrasound?

A. BI-RADS 1—normal

B. BI-RADS 2—benign

C. BI-RADS 3—probably benign

D. BI-RADS 4—suspicious

4. If this mammogram was the patient’s first mammogram in your office, which statement regarding prior examinations is not correct?

A. It can be expensive to obtain prior mammograms.

B. No prior examinations are needed to evaluate the coarse calcification.

C. A patient who has a history of breast cancer should always have her mammogram compared with prior examinations.

D. Prior mammograms are not needed for this benign mammogram.

ANSWERS

CASE 42

Calcification on Ultrasound

1. A, B, and D

2. B

3. B

4. D

Reference

Stavros AT. Breast Ultrasound. Philadelphia: Lippincott Williams & Wilkins; 2004.

Cross-Reference

Ikeda D. Breast Imaging. In: THE REQUISITES. 2nd ed Philadelphia: Saunders; 2010:83.

Comment

Fibroadenoma is a common breast lesion. It is often seen in all types of patients, including patients who develop malignancy. In this patient, the dense, calcified fibroadenoma existed for many years before the malignancy was detected (see the figures). Calcifications in the breast that has undergone lumpectomy need to be evaluated because recurrence may calcify. However, a large, coarse calcification such as this is benign and needs no further evaluation. This case illustrates how such a benign calcification can have a worrisome appearance on ultrasound (see the figures).

To distinguish a shadowing large calcification from a shadowing suspicious mass, look for the curvilinear dense rim along the anterior wall. This rim is the anterior margin of the calcification, which causes acoustic shadowing. The soft tissue mass of the fibroadenoma surrounding the calcification may also be seen on ultrasound. Also look at the mammogram to correlate the location of the shadowing structure with the location of the calcification on the mammogram. If the shadowing mass corresponds to the location of a coarse calcification on the mammogram, no further evaluation is needed for the shadowing mass.

CASE 43

History: A 60-year-old woman had subglandular silicone implants placed 30 years ago. A mammogram obtained 6 years ago showed possible rupture, which was confirmed with MRI. She had the implants surgically removed. The routine screening mammogram following this surgery is shown.

1. What should be included in the differential diagnosis of the mammogram shown? (Choose all that apply.)

A. Fat necrosis in both breasts

B. Bilateral, locally advanced breast cancer

C. Bilateral retained implant capsule

D. Ductal carcinoma in situ

2. What is the next step in management?

A. Stereotactic biopsy

B. Referral to plastic surgeon

C. MRI

D. Physical examination

3. What is the “retained capsule”?

A. Free silicone that has extravasated from the implant

B. The envelope of the silicone implant that was left behind in the surgical bed

C. The fibrous capsule, formed by the patient, surrounding the implant was not removed

D. It is the same as “retained siliconoma”

4. Can saline implants also show calcification on the mammogram?

A. No, only silicone implants calcify

B. Yes, because the fibrous capsule calcifies, not the implant

C. Yes, because saline implants have a silicone envelope

D. Yes, but only in the subglandular position

ANSWERS

CASE 43

Implant Removal with Retained Capsule

1. A and C

2. B

3. C

4. B

References

Caskey CI, Berg WA, Hamper UM, et al. Imaging spectrum of extracapsular silicone: correlation of US, MR imaging, mammographic, and histopathologic findings. Radiographics. 1999;19:S39–S51. (Spec No):

Frazer CK, Wylie EJ. Mammographic appearances following breast prosthesis removal. Clin Radiol. 1995;50(5):314–317.

Hardt NS, Yu L, LaTorre G, et al. Complications related to retained breast implant capsules. Plast Reconstr Surg. 1995;95(2):364–371.

Rockwell WB, Casey HD, Cheng CA. Breast capsule persistence after breast implant removal. Plast Reconstr Surg. 1998;101(4):1085–1088.

Sinclair DS, Spigos DG, Olsen J. Case 2. Retained silicone and fibrous capsule in the right breast and retained fibrous capsule in the left breast after removal of implants. AJR Am J Roentgenol. 2000;175(3):862–864.

Stewart NR, Monsees BS, Destouet JM, et al. Mammographic appearance following implant removal. Radiology. 1992;185(1):83–85.

Cross-Reference

Ikeda D. Breast Imaging. In: THE REQUISITES. 2nd ed Philadelphia: Saunders; 2010:343.

Comment

Implants are placed in the breast to augment the size of the breast. The implants are composed of a silicone elastomer shell and contain either silicone gel or saline as the filler. They are placed either in front of the pectoral muscle (see the figures), termed subglandular, or behind the pectoral muscle, termed subpectoral.

A complication of implants is the formation of the fibrous capsule. The fibrous capsule is the body’s immune response to the foreign material—an attempt to “wall off” the implant. This fibrous capsule can calcify, which often has a bizarre appearance on mammogram, as it forms plaques over the curved sheet of fibrous tissue surrounding the implant (see the figures).

When silicone implants rupture, the implant may be removed surgically. Removing the fibrous capsule was thought to be unnecessary in the past because this added morbidity and expense to the surgical procedure. There was evidence that because the capsule formed as a response to the implant, it would resorb spontaneously after the implant was removed. More recent evidence showed that spontaneous resorption did not always occur, and potential problems could arise from the retained capsule, including serous effusion, expansile hematoma, and siliconomas.

Mammography of the retained capsule most commonly shows masses at the site where the implant had been present, often with unusual calcifications (see the figures). These calcified forms have been termed “gold leaf” and “tin foil.” These calcified masses may be confused with carcinoma, so it is important to obtain the history of explantation from the patient to avoid unnecessary concern and biopsy. Free silicone and silicone granulomas are also commonly seen as well as silicone in the axillary nodes, not present in this patient. The retained capsule was excised as a separate surgical procedure in this patient.