CASE 105
History: A 45-year-old African-American woman presents with a palpable area of concern in the upper inner right breast found on self-breast examination. She has no family history of breast cancer.
1. What should be included in the differential diagnosis? (Choose all that apply.)
2. Ultrasound-guided biopsy was performed and showed polygonal cells in bundles and cords, with abundant granular eosinophilic cytoplasm and stromal fibrosis. What is the next step in management?
A. Repeat of ultrasound-guided biopsy
B. Follow-up mammogram, ultrasound, and MRI in 6 months
D. Lumpectomy and radiation therapy
3. Granular cell tumors may appear as any of the following except:
B. Partially circumscribed mass with calcifications
C. Partially circumscribed mass without calcifications
D. Partially ill-defined hypoechoic mass with posterior acoustic shadowing
4. Which of the following statements regarding granular cell tumors is true?
A. They are typically found in the breast.
B. They may mimic breast cancer both clinically and on imaging.
C. They usually occur as an incidental finding on screening mammogram.
D. They are a subtype of ductal breast carcinoma.
ANSWERS
CASE 105
Granular Cell Tumor
1. A and D
2. C
3. B
4. B
References
Adeniran A, Al-Ahmadie H, Mahoney M, et al. Granular cell tumor of the breast: a series of 17 cases and review of the literature. Breast J. 2004;10(6):528–531.
Porter GJ, Evans AJ, Lee AH, et al. Unusual benign breast lesions. Clin Radiol. 2006;61(7):562–569.
Comment
Granular cell tumors are rare benign lesions, thought to derive from Schwann cells. They can be located in almost any tissue, but the most common site involved is the tongue. Approximately 5% to 8% of cases occur in the breast, and they are more common in premenopausal African-American women.
Granular cell tumors mimic breast cancer both clinically and on imaging. Clinically, they usually manifest as a firm, painless, palpable mass, usually fixed to the pectoral fascia, which may cause retraction of the skin. However, in contrast to breast carcinomas, which usually occur in the upper outer quadrant, granular cell tumors are predominantly found in the upper inner quadrant of the breast (area of cutaneous innervation by the supraclavicular nerve).
The appearance on mammography is more frequently a poorly defined or spiculated mass, without calcifications. On ultrasound, they may appear as an irregular or spiculated mass with posterior acoustic shadowing and less frequently as a circumscribed mass. Reported MRI findings of granular cell tumors in sites other than the breast show variable T2 signal intensity (from low or intermediate to high compared with the adjacent muscle) and low to intermediate signal on T1-weighted images; both homogeneous and peripheral enhancement have been described after contrast agent administration (see the figures).
Biopsy should be performed to obtain a definitive diagnosis. Although these are benign lesions, treatment is wide local excision, owing to their potential local recurrence. Rare malignant cases have been reported.
CASE 106
History: A 54-year-old woman presents for screening mammogram.
1. What should be included in the differential diagnosis for the calcifications in the far posterior upper outer right breast? (Choose all that apply.)
B. Atypical ductal hyperplasia
2. Which of the following situations does not make stereotactic biopsy difficult (requiring special positioning of the patient) or technically impossible?
B. Central cluster of microcalcifications measuring 2 to 3 mm
C. Microcalcifications located close to the chest wall
D. Microcalcifications located in the axillary tail of the breast
3. Which of the following is not a special maneuver in patient and breast positioning during stereotactic biopsy to improve visualization of posterior or axillary tail microcalcifications?
A. Pull the breast, gently but firmly, through the opening of the stereotactic table.
B. Encourage the patient to relax the chest muscles as much as possible.
C. Place the patient’s arm through the breast opening of the table.
D. Roll the patient into a supine position.
4. Which of the following is not a limitation of stereotactic biopsy compared with ultrasound-guided biopsy?
A. Compression of the breast is a necessity.
B. The patient must remain still during the biopsy procedure.
C. The patient must lie on her stomach.
D. The patient is typically lying supine.
ANSWERS
CASE 106
Difficult Stereotactic Biopsy—Calcifications in the Axillary Tail of the Breast
1. A, B, and C
2. B
3. D
4. D
References
Jackman RJ, Marzoni FA Jr. Stereotactic histologic biopsy with patients prone: technical feasibility in 98% of mammographically detected lesions. AJR Am J Roentgenol. 2003;180(3):785–794.
Cross-Reference
Ikeda D. Breast Imaging. In: THE REQUISITES. 2nd ed Philadelphia: Saunders; 2010:215.
Comment
Stereotactic biopsy is the method used when indeterminate or suspicious calcifications are seen on a mammogram (see the figures). If there is no associated mass, these lesions may be seen only on the mammogram. To obtain a biopsy specimen of these lesions, stereotactic biopsy, a mammographically derived procedure, is performed. This procedure may be performed with a special add-on unit that is attached to the regular mammogram device, and the procedure is completed with the patient sitting in a chair. A specially designed table may also be used. On this table, the patient lies prone, and the breast is pulled through a round opening in the table. The biopsy is performed below the patient, by a radiologist sitting on a chair.
In 2003, nearly 2000 stereotactic biopsies and reasons for incomplete and canceled studies were reviewed. When stereotactic biopsies were canceled for technical reasons, most were canceled because the lesion was too close to the chest wall. Lesions close to the chest wall and in the axillary tail of the breast are difficult to position in the stereotactic window for biopsy. However, maneuvers can be used to visualize posterior lesions better so that they can be sampled stereotactically.
The breast should be pulled, gently but firmly, as completely as possible down through the opening in the stereotactic table. The patient should be encouraged to relax the chest muscles as much as possible. If the lesion cannot be seen, the patient’s arm can be placed through the breast opening of the table, which drops more of the axillary area into position for biopsy. The patient also can be rolled into a slightly decubitus position, with the side of interest down.
Biopsy specimens of calcifications in the axillary tail may be easier to obtain from the mediolateral oblique (MLO) or mediolateral approach rather than the craniocaudal (CC) approach. From the lateral approach, the calcifications are closer to the skin (see the figures). A biopsy clip should be placed at the site of biopsy after the procedure, so that if excision is needed, the area can be easily localized. Placement of a clip is especially important in difficult biopsies and if the cluster of microcalcifications is too small because it may be completely removed on the core biopsy. Specimen radiograph should be performed prior to clip placement, to ensure that the target has been sampled.
The mammogram obtained after biopsy in this case shows the clip at the site where the microcalcifications had been present. Histopathology of the calcifications on biopsy was atypical ductal hyperplasia, which should be surgically excised.
CASE 107
History: Two patients undergo routine screening mammograms. New calcifications are seen in the subareolar breast in each patient. Magnification views are shown.
1. What should be included in the differential diagnosis for both patients? (Choose all that apply.)
B. Ductal carcinoma in situ (DCIS)
2. What is the next step in management?
A. Follow-up diagnostic mammogram in 1 year with magnification views
B. Short-interval follow-up magnification views in 6 months
D. Image-guided vacuum-assisted needle biopsy
3. The needle biopsy result for both patients showed intraductal papilloma. Which of the following is not recommended?
B. Short-interval follow-up magnification views in 6 months
D. Follow-up ultrasound examination in 6 months
4. What symptom is commonly associated with subareolar intraductal papilloma?
ANSWERS
CASE 107
Calcified Subareolar Masses
1. B, C, and D
2. D
3. A
4. D
References
Al Sarakbi W, Worku D, Escobar PF, et al. Breast papillomas: current management with a focus on a new diagnostic and therapeutic modality. Int Semin Surg Oncol. 2006;3:1.
Cross-Reference
Ikeda D. Breast Imaging. In: THE REQUISITES. 2nd ed Philadelphia: Saunders; 2010:120.
Comment
A papilloma is a tumor that arises from ductal epithelium. The term papilloma includes solitary papilloma (as in this case, see the figures), multiple papillomas, and juvenile papillomatosis. Intraductal papilloma is classified as a benign tumor of the breast, although the condition of multiple peripheral papillomas confers an increased risk of malignancy. Solitary papillomas, as in this case, are typically found in large ducts in the retroareolar breast and are less likely to be associated with DCIS. A solitary papilloma in a large duct is the most common presentation of all papillary lesions and affects an older age group compared with multiple peripheral papillomas.
Surgical consultation is recommended for women who have a biopsy result showing papilloma because there is an increased incidence of DCIS within the papilloma, which may not be found on a needle biopsy sample. This risk is reported to be 20%. There is some controversy surrounding this issue if a benign papilloma is found at core biopsy. However, if atypia or malignancy is present in the core specimen, surgical excision is universally recommended. There seems to be no statistical difference between 11-gauge and 14-gauge needle in the cancer yield in excisional biopsy in benign papillomas.
Papillomas may twist on the fibrovascular stalk and can cause bloody or clear spontaneous nipple discharge. Papilloma is the most common cause of pathologic nipple discharge (in 40% to 70% of women). However, most women with an intraductal papilloma are asymptomatic. Detection on mammogram is limited because these masses are contained within a duct that appears outwardly normal. When calcifications are present, mammographic detection increases (see the figures). A papilloma may also appear on mammogram as a well-defined mass.
CASE 108
History: A 56-year-old woman has a 1-year history of bilateral bloody nipple discharge. Mammogram and ultrasound are both negative. Galactography was unsuccessful. Clinical breast examination is positive only for easily elicited bloody discharge from both nipples; no masses are palpated.
1. What should be included in the differential diagnosis of the bilateral, post–contrast subtraction MRI images shown? (Choose all that apply.)
A. Bilateral intraductal carcinoma
C. Bilateral duct ectasia with debris
2. What is the management of this imaging finding?
A. Targeted ultrasound with biopsy
C. Follow-up in 6 months because these masses are likely benign
3. Is MRI useful in this clinical setting?
A. No, because approximately 25% of papillomas do not enhance
B. No, because galactography can provide the same information
C. Yes, because MRI can provide the location and number of enhancing masses
D. No, because the surgeon can perform central duct excision
4. Which of the following is not pathologic nipple discharge?
A. Blackish and greenish discharge from multiple orifices
B. Spontaneous watery discharge
D. Dark maroon and spontaneous
ANSWERS
CASE 108
MRI of Nipple Discharge
1. A, B, and D
2. B
3. C
4. A
References
An HY, Kim KS, Yu IK, et al. Image presentation. The nipple-areolar complex: a pictorial review of common and uncommon conditions. J Ultrasound Med. 2010;29(6):949–962.
Cross-Reference
Ikeda D. Breast Imaging. In: THE REQUISITES. 2nd ed Philadelphia: Saunders; 2010:383.
Comment
Nipple discharge should be clinically evaluated because it may be a symptom of breast cancer. However, most causes of nipple discharge are benign. Pathologic nipple discharge includes spontaneous discharge that is unilateral, persists, and can range from clear (watery) to serous to bloody. Nonpathologic discharge is typically elicited only on squeezing the nipple; benign discharge can be milky, green, or gray to black. Nonpathologic discharge typically occurs in more than one orifice of the nipple and may be bilateral.
Masses that can cause nipple discharge include papillary masses arising in the lactiferous ducts, ranging from benign papilloma to papillary DCIS to invasive papillary cancer. Other masses include nipple adenoma, which is a proliferation of tubules in the duct, and DCIS and invasive ductal carcinoma.
MRI can be useful in the diagnosis of pathologic nipple discharge when standard diagnostic imaging fails. Intraductal masses may be the cause of discharge, and if the mass is not calcified, it is unlikely to be seen on mammography. Ultrasound is useful to evaluate the cause of discharge, but debris in the duct can look like a mass. With ultrasound, it is helpful to orient the transducer along the long axis of the duct. Galactography is the standard interventional method of evaluating discharge. It may be technically difficult to cannulate the duct, and distal nipple masses, such as in this patient (see the figures), can block the placement of the cannula.
Papillomas do not consistently enhance on MRI. Approximately 75% are seen after contrast injection, and kinetics range from slow, persistent enhancement to a malignant profile. Other findings on MRI include an enlarged duct, with fluid hyperintense on T2 images, with an intraductal hypointense mass.
Biopsy may be performed with imaging guidance if the lesion is seen on ultrasound or contains calcifications that can be targeted for stereotactic biopsy. Biopsy of masses in the nipple is technically difficult using any imaging modality, and these masses should be surgically excised.
CASE 109
History: A 44-year-old woman is scheduled for surgery to remove a mass in the left breast after core biopsy.
1. What should be included in the differential diagnosis for the ultrasound image of the mass in the left breast? (Choose all that apply.)
2. Which of the following statements regarding the best selection of imaging modality to guide needle localization is false?
A. Masses are generally localized under ultrasound guidance.
B. Calcifications are generally localized under mammographic guidance.
C. Areas of non-masslike enhancement are generally localized under MRI guidance.
D. Needle localization can be performed only under mammographic guidance.
3. Which of the following are the correct steps, in order, to perform ultrasound-guided needle localization?
4. Which of the following statements regarding ultrasound-guided needle localization is true?
A. It may not be necessary to send mammogram films to the operating room.
B. Obtaining a radiograph of the specimen is unnecessary.
C. The specimen radiograph is evaluated by the surgeon in the operating room.
D. The surgeon does not need to be notified of the specimen radiograph findings.
ANSWERS
CASE 109
Ultrasound-Guided Needle Localization
1. A, C, and D
2. D
3. B
4. A
References
DePalo AJ. Surgical considerations in needle localization procedures. Semin Surg Oncol. 1991;7(5):253–256.
Klimberg VS. Advances in the diagnosis and excision of breast cancer. Am Surg. 2003;69(1):11–14.
Cross-Reference
Ikeda D. Breast Imaging. In: THE REQUISITES. 2nd ed Philadelphia: Saunders; 2010:200.
Comment
Needle localization procedures are less frequently performed at the present time because of the wide acceptance of percutaneous core biopsies. The most common indication for needle localization is excision of nonpalpable high-risk lesions or carcinoma diagnosed at core biopsy. Another indication is to aid in the excision of a nonpalpable lesion when biopsy with imaging guidance cannot be performed.
Needle localization may be performed under mammographic, ultrasound, or MRI guidance. The selection of the guiding modality should be based on the ease of seeing the lesion. Generally, calcifications are localized under mammographic guidance, masses are localized under ultrasound guidance, and areas of non-masslike enhancement are localized under MRI guidance.
For ultrasound-guided needle localization, the patient is positioned so that the skin entry site for placement of the localizing needle and hook wire is as close to the lesion as possible. The needle length is chosen by measuring the distance from the closest skin surface to the site of the lesion on the ultrasound screen. After the lesion is identified and the skin entry site has been selected, the skin is cleansed and anesthetized, and the needle is placed into the breast, parallel to the chest wall (see the figures). Needle placement into the lesion is confirmed by ultrasound in orthogonal planes (needle parallel and perpendicular to the transducer) in real time during the procedure. The needle is adjusted so that the tip is at or just beyond the lesion. The hook wire is placed through the needle and secured in the breast tissue. Some surgeons prefer to keep the needle in the breast to aid in localizing the lesion in the operating room, whereas other surgeons prefer to remove the needle and keep only the wire in the breast. Some surgeons prefer blue dye to be injected into the lesion to aid removal.
The ultrasound images are sent to the operating room, with the lesion circled. Some surgeons prefer that mammographic films also be sent to the operating room to serve as additional guidance. A specimen radiograph is obtained in every case (see the figures), but the lesion may not be evident radiographically, and ultrasound of the specimen may be necessary to confirm that the lesion has been removed. To aid the surgeon, a metal BB may be placed on the skin at the needle insertion site before the radiograph is taken. An “X” may be marked on the patient’s skin overlying the mass because the needle is not placed through the skin directly over the mass.
The radiologist must review the specimen to ensure that the lesion has been removed (or sampled, depending on the case). The surgeon is notified of the findings, and if the lesion has not been removed or adequately sampled, the surgeon should be directed to obtain more tissue.
CASE 110
History: A 44-year-old woman had invasive lobular carcinoma (ILC) diagnosed 3 years previously, was treated with breast conservation therapy, and is asymptomatic. She now presents for her annual mammogram.
1. What should be included in the differential diagnosis for the images shown? (Choose all that apply.)
A. Normal postoperative mammogram and MRI
B. Recurrent carcinoma at the lumpectomy site
C. Fat necrosis at the lumpectomy site
D. Residual disease at the lumpectomy site
2. Is ILC more likely to have recurrence compared with invasive ductal carcinoma not otherwise specified (IDC NOS)?
A. Yes, because this tumor is more likely multifocal and multicentric
B. Yes, because ILC is typically larger at diagnosis compared with IDC
C. No, the recurrence rates are similar
D. Yes, because of the tumor biology of cells infiltrating in single file in ILC
3. What is the management of recurrent disease?
D. Surgery and additional radiation therapy
4. What is the most common presentation of recurrent disease after breast conservation?
A. Mass and/or calcifications away from the lumpectomy site, within 3 years of treatment
B. Mass and/or calcifications at the lumpectomy site, on the first mammogram after treatment
C. Mass and/or calcifications in the opposite breast, 3 years or more after treatment
D. Mass and/or calcifications at the lumpectomy site, 18 months or more after treatment
ANSWERS
CASE 110
Invasive Lobular Carcinoma with Recurrence
1. B, C, and D
2. C
3. A
4. D
References
Arpino G, Bardou VJ, Clark GM, et al. Infiltrating lobular carcinoma of the breast: tumor characteristics and clinical outcome. Breast Cancer Res. 2004;6(3):R149–R156.
Cross-Reference
Ikeda D. Breast Imaging. In: THE REQUISITES. 2nd ed Philadelphia: Saunders; 2010:314. 324
Comment
ILC is more difficult to detect on mammography, ultrasound, and MRI compared with IDC. It is more likely to spread through the breast in single files of cells, inciting little desmoplastic reaction by the host. For this reason, ILC is larger at diagnosis compared with IDC NOS, more likely to need reoperation because of positive margins at surgery, and more likely to necessitate mastectomy at the time of surgery for lumpectomy because of positive margins. It is also more commonly multifocal and multicentric and more likely to have contralateral breast involvement.
The above-mentioned characteristics do not affect the recurrence rate or the disease-free survival. In one large series reviewing more than 50,000 cases of early breast cancer, the recurrence rate of ILC was slightly lower than the recurrence rate of IDC NOS, although this was not clinically significant. The two breast cancer types should be considered to have essentially the same clinical outcome; the failure rate of breast cancer treatment for both types is approximately 1% per year.
The patient in this case was 41 years old at the time of diagnosis, making her younger than the average patient with ILC (average age is 65 years). She had a normal screening mammogram and felt a palpable mass in her left breast 2 months later (false-negative mammogram is common with ILC). At the time of the work-up for the palpable mass, the diagnostic mammogram was negative, and ultrasound showed an 8-mm mass. Ultrasound is more sensitive than mammography in ILC but tends to underestimate the size of the tumor, as in this patient. MRI was negative; no enhancement was seen at the tumor site. No enhancement is rare for infiltrating cancers but more common with ILC than with IDC. When MRI shows ILC as an enhancing mass, it more accurately shows tumor size than mammography and ultrasound. At surgery, this patient required two reexcisions to obtain clear margins, which is more common with ILC than with IDC.
At 3 years after surgery, mammogram showed increased density at the lumpectomy site (see the figures); follow-up imaging had been unremarkable at 1 year after lumpectomy. MRI (see the figures) showed a new area of non-masslike enhancement at the lumpectomy site. Ultrasound and ultrasound-guided core biopsy were performed and showed ILC at the lumpectomy site, consistent with recurrence. The patient underwent mastectomy.
CASE 111
History: A 37-year-old woman who is BRCA-positive has a tiny irregular mass in the outer left breast found on screening MRI. The mass showed avid enhancement with gadolinium and was new compared with prior MRI studies. It was visible only on MRI.
1. What should be included in the differential diagnosis for the mass in the left breast? (Choose all that apply.)
2. Indications for MRI-guided needle localization include all of the following except:
A. Areas of non-masslike enhancement
B. Cluster of amorphous microcalcifications
C. Lesions not visible on mammography or ultrasound
D. Lesions visible on MRI, with equivocal results on mammogram and ultrasound
3. Which of the following statements regarding MRI-guided needle localization procedures is true?
A. The patient is positioned supine within a dedicated breast coil.
B. No special positioning of the breast is required.
C. The needle should be placed at the site of the lesion.
D. Adequate placement of the hook wire is confirmed after the patient is released from compression.
4. Which of the following statements is false?
A. A two-view mammogram is performed after MRI-guided localization.
B. Obtaining a radiograph of the specimen is unnecessary.
C. The specimen radiograph is evaluated by the radiologist.
D. The surgeon is notified of the specimen radiograph findings.
ANSWERS
CASE 111
MRI-Guided Needle Localization
1. A, C, and D
2. B
3. C
4. B
References
Klimberg VS. Advances in the diagnosis and excision of breast cancer. Am Surg. 2003;69(1):11–14.
Cross-Reference
Ikeda D. Breast Imaging. In: THE REQUISITES. 2nd ed Philadelphia: Saunders; 2010:275.
Comment
Needle localization procedures generally are less frequently performed because of the wide acceptance of percutaneous core biopsies. MRI-guided needle biopsy and needle localization procedures are performed in lesions not clearly visible on either mammogram or ultrasound, such as areas of non-masslike enhancement. MRI-guided needle biopsy could be performed with a clip marker placed in the breast after biopsy. The clip can be localized mammographically if excision is needed.
In this case, the lesion was only seen on MRI, had irregular margins, showed avid enhancement with gadolinium with rapid washout, and was new compared with prior MRI examinations (see the figures). MRI-guided biopsy could have been performed, but the patient requested excision.
For MRI-guided needle localization, the patient is positioned prone within a dedicated breast coil, and the breast is gently compressed with a special compression paddle that includes a grid and a needle guide. Compression minimizes motion and allows consistent lesion location, but overly tight compression should be avoided because tight compression may hinder or delay enhancement of the lesion. After positioning, the patient is scanned, and when the lesion is identified, it is triangulated in a similar way as on mammographic guided localization (this can be done manually or with computer-assisted detection [CAD]). The needle is placed at the site of the lesion, and the hook wire is released (see the figures). Adequate placement of the hook wire is confirmed with MRI before the patient is released from compression.
The needle localization procedure can be done from a lateral or medial approach. Some breast coils allow medial access, whereas others offer only a lateral approach, which can be problematic when the lesion is located in the medial aspect of the breast because the distance from the skin would not be the shortest, and the available needle localization devices may not reach the lesion.
A two-view mammogram is performed to show the location of the wire in the breast, even if the lesion was not previously visible mammographically. Surgeons may need this mammogram in the operating room to help plan the surgical procedure. The mammogram may reveal an abnormality that was not seen before localization. Also, these images provide a baseline for mammograms after biopsy.
A specimen image cannot be obtained with MRI. However, a mammographic specimen radiograph is performed. The radiologist reviews the specimen and notifies the surgeon of the findings. In this case, a small spiculated mass was visualized within the specimen (see the figures). Histologically, this mass was a 5-mm invasive ductal carcinoma.
CASE 112
History: A 60-year-old woman has a history of right breast cancer, diagnosed as ductal carcinoma in situ (DCIS), 11 years before. She has extremely dense breasts on mammogram and is followed annually with mammogram and MRI. Previous MRI examinations have been negative.
1. What should be included in the differential diagnosis for the left breast MRI post–contrast subtraction images shown? (Choose all that apply.)
A. Infiltrating ductal carcinoma
2. What is the next step in management for this developing lesion?
A. Because the mass is tiny, repeat MRI in 6 months.
B. Because the morphology of the mass is benign, return the patient to routine evaluation.
3. Which of the following statements about MRI-guided biopsy is not true?
B. The breast is in compression.
C. A grid is used to help localize the mass.
D. A vacuum-assisted biopsy apparatus is preferred for sampling.
4. Which of the following is not an appearance of DCIS on MRI?
D. Large mass with spiculated margins
ANSWERS
CASE 112
MRI-Guided Biopsy
1. A, B, and C
2. D
3. A
4. D
References
Han BK, Schnall MD, Orel SG, et al. Outcome of MR-guided breast biopsy. AJR Am J Roentgenol. 2008;191(6):1798–1804.
Cross-Reference
Ikeda D. Breast Imaging. In: THE REQUISITES. 2nd ed Philadelphia: Saunders; 2010:265. 277
Comment
MRI is a well-established modality for evaluation of the breast in selected patients. The postmenopausal patient in the present case has a personal history of right breast cancer and has dense breasts, which limit mammographic interpretation. She has been evaluated with mammogram and supplementary MRI for several years (see the figures). On the most recent MRI, a new 5-mm mass was noted in the subareolar left breast (see the figures).
Targeted ultrasound, or “second-look” ultrasound, is a useful examination after MRI shows a suspicious mass. If the lesion is found on ultrasound, ultrasound-guided biopsy is faster to perform and more easily tolerated by the patient. However, the use of targeted ultrasound should be tailored to the patient and to the MRI finding. Very small masses, non-masslike enhancement, and ductal enhancement can be difficult to identify on ultrasound. If a mass is not seen on targeted ultrasound, the finding cannot be presumed benign; in one large series, 14% of such lesions were malignant.
MRI-guided biopsy can be performed relatively easily and is similar to stereotactic biopsy with certain important differences. The contrast medium washes out of the breast lesion quickly, so once the location of the mass is noted, the patient may not move because the mass cannot be retargeted without administering more contrast medium. As in stereotactic biopsy, the patient is placed in prone position. With MRI-guided biopsy, the breast is only slightly compressed (see the figures). The compression cannot be too tight because the contrast medium may be inhibited from entering the breast blood vessels. The compression paddle has a grid to facilitate the localization of the biopsy site within the breast. A marker is placed on the skin, in one of the grid openings (see the figures), and the contrast-enhanced study is performed. The x, y, and z coordinates of the lesion are noted on the image, and then the location is compared with the location of the marker (called a fiducial). The appropriate x and y lesion location is noted on the skin, and the distance to the lesion from the skin (the z axis) is calculated. This localization of the mass can be accomplished by a computer-assisted detection (CAD) system or can be done by hand.
The skin is cleansed, local anesthesia is given, and the biopsy trocar is placed, similar to a stereotactic biopsy. When the desired location is reached, the metal trocar is replaced by an MRI-compatible stylet, and images are obtained to check the location of the stylet (see the figures). If the location is accurate, the stylet is removed; the biopsy device is placed through the sheath, and the samples are taken. With a vacuum-assisted device, multiple samples can be taken easily without removing the device from the breast. A clip is placed after the samples are taken, and additional images are obtained to assess the biopsy cavity and location of the clip, relative to the location of the mass as initially noted at the beginning of the examination. A mammogram is obtained after the biopsy to document the clip location.
The malignancy rate of MRI-detected areas of abnormal enhancement is approximately 20% to 60%. Lesions that are found to be benign by MRI-guided biopsy should be followed in 6 months with repeat MRI to ensure that the finding is smaller or resolved. If the lesion is unchanged or larger on follow-up, biopsy of the mass should be repeated.
In this patient, the small mass was DCIS. DCIS can have multiple features on MRI, ranging from a small mass to clumped enhancement in a ductal distribution to segmental, non-masslike enhancement. Kinetics is variable, with a slow or a rapid initial increase, with persistence or plateau. In the older literature, 25% to 40% of DCIS that was seen on mammography was not recognized on MRI. However, newer studies show DCIS detection on MRI to be greater than 90%.
CASE 113
History: A 43-year-old woman with juvenile-onset diabetes presents for a routine screening mammogram. A palpable mass is noted in the right subareolar breast by the technologist when positioning her for the mammogram.
1. What should be included in the differential diagnosis? (Choose all that apply.)
2. Which of the following statements regarding diabetic mastopathy is true?
A. It typically occurs in patients with type 2, non–insulin-dependent diabetes.
B. Incidence is similar in women and men.
D. The most common clinical presentation is an incidental mammographic finding.
3. Which of the following is not an imaging finding in diabetic mastopathy?
A. Extensive microcalcifications on mammogram
B. Poorly defined mass or dense focal asymmetry on mammogram
D. Poorly defined mass or areas of intense acoustic shadowing on ultrasound
4. Which of the following statements regarding diagnosis and management of diabetic mastopathy is false?
A. Tissue diagnosis is necessary to exclude malignancy.
B. Fine-needle aspiration is very accurate in providing a diagnosis of diabetic mastopathy.
C. Core or excisional biopsies are often necessary for conclusive diagnosis of diabetic mastopathy.
D. No specific treatment is necessary when diabetic mastopathy is diagnosed on biopsy.
ANSWERS
CASE 113
Diabetic Mastopathy
1. A, B, and D
2. C
3. A
4. B
References
Camuto PM, Zetrenne E, Ponn T. Diabetic mastopathy: a report of 5 cases and a review of the literature. Arch Surg. 2000;135(10):1190–1193.
Cross-Reference
Ikeda D. Breast Imaging. In: THE REQUISITES. 2nd ed Philadelphia: Saunders; 2010:400.
Comment
Diabetic mastopathy is an uncommon condition that occurs in patients with long-standing insulin-dependent diabetes. It is most often diagnosed in premenopausal women and has been reported only rarely in men. The most common presentation is a firm, palpable mass that may mimic carcinoma on breast examination, as in the patient in this case. Patients frequently have associated complications from diabetes, such as renal disease, retinopathy, and cardiac disease.
The mammographic findings in diabetic mastopathy are usually a poorly defined mass or a dense focal asymmetry (see the figures). Patients also may have mammographically detected vascular calcifications as a complication of long-standing diabetes. However, because many of these patients are young, the palpable mass may not be mammographically visible owing to surrounding dense breast tissue (see the figures). Ultrasound may show a poorly defined mass or areas of intense acoustic shadowing (see the figures).
The diagnosis of diabetic mastopathy may be suggested with the appropriate clinical history and ultrasound features, but tissue diagnosis is necessary to exclude malignancy. Fine-needle aspiration cytology has been reported to be nondiagnostic in half of lesions because diabetic fibrous tissue contains little cellular material. Core or excisional biopsies are often necessary for conclusive diagnosis of diabetic mastopathy. Core biopsy reveals thick bundles of collagen and periductal, lobular, and vascular inflammatory infiltrates.
An autoimmune etiology has been postulated for this condition. No association has been described between diabetic mastopathy and carcinoma. No specific treatment is necessary for this entity.
CASE 114
History: A 43-year-old woman presents with left bloody nipple discharge.
1. What should be included in the differential diagnosis? (Choose all that apply.)
B. Ductal carcinoma in situ (DCIS)
2. Which of the following statements regarding imaging of DCIS is false?
A. The mammographic appearance consists of microcalcifications.
B. The ultrasound appearance is characteristic and consists of an intraductal solid filling defect.
C. The MRI appearance consists of non-masslike enhancement.
D. DCIS can appear on mammography as a mass.
3. Signs of microinvasion or invasion in high-grade DCIS include all of the following except:
A. Palpable mass on clinical examination
B. Extensive linear, branching, pleomorphic, or casting calcifications
C. Irregular hypoechoic area or mass on ultrasound
D. Focal area of clumped non-masslike enhancement in a ductal distribution on MRI
4. Which of the following statements regarding management or prognosis of DCIS is true?
B. The best imaging modality to guide percutaneous biopsy is ultrasound.
D. After adequate treatment, the recurrence rate of high-grade DCIS (comedocarcinoma) is low.
ANSWERS
CASE 114
High-Grade Ductal Carcinoma In Situ
1. B and D
2. B
3. D
4. C
References
Estevez L, Alvarez I, Segui MA, et al. Current perspectives of treatment of ductal carcinoma in situ. Cancer Treat Rev. 2010;36(7):507–517.
Cross-Reference
Ikeda D. Breast Imaging. In: THE REQUISITES. 2nd ed Philadelphia: Saunders; 2010:65. 170
Comment
DCIS is a type of noninvasive cancer in which the cancer cells have not extended beyond the basal membrane of a duct. DCIS accounts for approximately 20% to 30% of the cancers detected on screening mammogram.
DCIS is classified according to its nuclear grade as low, intermediate, and high grade and morphologically as cribriform, micropapillary, solid, and comedo subtypes. The presence or absence of necrosis is also important in classification of DCIS. High-grade DCIS (comedocarcinoma) is a poorly differentiated form of DCIS that tends to have continuous growth along the ductal system (other subtypes of DCIS have a higher incidence of discontinuous or skip-type growth patterns).
High-grade DCIS appears on mammography as linear, branching, pleomorphic, or casting microcalcifications (see the figures). Because of its tendency to have a continuous growth pattern, the linear branching calcifications seen on mammography may provide an accurate estimate of extent of disease.
DCIS is usually not seen on ultrasound. Occasionally—especially with newer equipment—microcalcifications can be visualized on ultrasound as hyperechoic dots, but the main contribution of ultrasound is to assess for possible additional invasive components (hypoechoic areas or mass or both).
On MRI, DCIS appears as non-masslike enhancement (usually clumped) in a linear, ductal, segmental, or regional distribution. MRI is useful to evaluate extent of disease, multifocality or multicentricity, and presence of contralateral disease. It may detect masses not seen on mammography, and it may show areas of noncalcified DCIS (see the figures).
To establish a diagnosis, stereotactic biopsy of microcalcifications is the best initial approach. When there are multifocal or multicentric areas of microcalcifications, biopsy specimens of any suspicious areas may be obtained to document extent of disease or at least the two most distant sites of microcalcifications. Ultrasound and MRI can be used to guide biopsy of a possible invasive component not detected with mammography.
As the volume of DCIS increases, the chance of microinvasion increases as well. When the extent of disease seen on mammography is 5 cm or greater, the likelihood of microinvasion is high enough that many surgeons perform a sentinel lymph node biopsy even though no invasion may have been documented histologically. Other symptoms and signs of microinvasion or invasion include palpable abnormality on self-examination or clinical examination, hypoechoic areas or mass on ultrasound, and enhancing mass on MRI.
Management of DCIS is the same as management of invasive carcinoma. Treatment includes surgery (lumpectomy or mastectomy), radiation therapy, and chemotherapy or hormonal therapy. Comedocarcinoma is associated with a higher rate of recurrence than other subtypes of DCIS because of the high nuclear grade and the radioresistance of the tumor.
CASE 115
History: A 48-year-old woman presents for screening mammogram.
1. What should be included in the differential diagnosis for the calcifications in the lower outer right breast? (Choose all that apply.)
B. Atypical ductal hyperplasia (ADH)
C. Ductal carcinoma in situ (DCIS)
D. Lobular carcinoma in situ (LCIS)
2. Stereotactic biopsy revealed ADH, fibrocystic change, and columnar cell change. ADH is usually found associated with which type of calcifications?
B. Pleomorphic microcalcifications
C. Regional amorphous microcalcifications
D. Fine, linear, branching microcalcifications
3. Which of the following statements regarding management of ADH is true?
A. ADH does not require further management.
4. What is the role of biopsy clip placement after stereotactic biopsy?
A. Biopsy clip placement after stereotactic biopsy of calcifications is unnecessary.
D. A biopsy clip placed after stereotactic biopsy is used as a guide for radiotherapy.
ANSWERS
CASE 115
Atypical Ductal Hyperplasia
1. A, B, and C
2. C
3. C
4. B
References
Jackman RJ, Birdwell RL, Ikeda DM. Atypical ductal hyperplasia: can some lesions be defined as probably benign after stereotactic 11-gauge vacuum-assisted biopsy, eliminating the recommendation for surgical excision?. Radiology. 2002;224(2):548–554.
Cross-Reference
Ikeda D. Breast Imaging. In: THE REQUISITES. 2nd ed Philadelphia: Saunders; 2010:230.
Comment
ADH is in the spectrum of hyperplastic changes of the breast that range from usual ductal hyperplasia to DCIS. ADH refers to the proliferation of monomorphic epithelial cells within the duct. ADH is found in approximately 5% of all biopsy specimens obtained for any type of calcifications but is frequently found associated with regional amorphous calcifications (approximately 20%). In this case, the patient had a focal area of clustered heterogeneous microcalcifications (see the figures) and was recalled for additional magnification views. On the additional views, some of the calcifications layer (suggestive of milk of calcium), but other calcifications are more irregular and raise concern for atypia or DCIS (see the figures). When a cluster of microcalcifications exhibits both benign and suspicious features, management should be based on the most suspicious features.
A patient with ADH diagnosed by core biopsy should always undergo excisional biopsy because of the high incidence of histologic underestimation of DCIS. When an 11-gauge vacuum-assisted core needle is used, there is an underestimation of malignancy of approximately 25% when ADH is the core needle diagnosis. Lesions on which core biopsies are performed and that are interpreted as ADH show various histology on excision, including fibrocystic change, ADH, DCIS, and invasive ductal carcinoma.
A biopsy clip should be placed at the site of biopsy so that the area can be easily localized if excision is needed. A clip is especially important if the cluster of microcalcifications is small because the microcalcifications may be completely removed on the core biopsy. Complete removal of all mammographic evidence of the microcalcifications at core biopsy does not obviate the need for excision. The goal of stereotactic biopsy is not complete removal, but rather adequate sampling of the lesion. In this patient, after excisional biopsy with complete removal of the lesion, the histopathology was low-grade DCIS. The vacuum-assisted core biopsy result was an underestimation of the disease present. Approximately 75% of underestimation of ADH is DCIS. The patient went on to definitive management of stage 0 breast cancer.
CASE 116
Initial presentation.
Six months later.
Six months later.
History: A 38-year-old woman in her third trimester of pregnancy presents with a palpable mass. Her family history is significant for breast cancer in her mother.
1. What should be included in the differential diagnosis for the initial presentation? (Choose all that apply.)
2. Why did the patient undergo ultrasound evaluation only at initial presentation?
A. Because ultrasound is always the first step in evaluating a palpable mass
B. Because of the patient’s age
C. Because the patient is pregnant
D. Because of her family history
3. Which of the following is not a reasonable option for further evaluation?
4. The patient underwent needle core biopsy. She complained of a persistent lump at the biopsy site 6 months later, larger than the original mass (mammogram and ultrasound are shown). The differential diagnosis includes all of the following except:
