DOI:10.2214/AJR.04.1949
AJR 2006; 186:1356-1360
© American Roentgen Ray Society
Mucocelelike Lesions of the Breast: Mammographic Findings with Pathologic Correlation
A. Jill Leibman1,2,
Christine N. Staeger1 and
Douglas A. Charney3
1 Department of Radiology, St. Luke's-Roosevelt Hospital, 1111 Amsterdam Ave.,
New York, NY 10025.
2 Present address: Department of Radiology, Jacobi Medical Center, 1400 Pelham
Parkway South, Bronx, NY 10461.
3 Department of Pathology, St. Luke's-Roosevelt Hospital, New York, NY.
Received December 22, 2004;
accepted after revision March 15, 2005.
Address correspondence to A. J. Leibman
(jill.leibman{at}nbhn.net).
Abstract
OBJECTIVE. The purpose of this study was to review the imaging
features of mucocelelike breast lesions, correlate the mammographic and
pathologic findings, and determine recommendations for management.
CONCLUSION. Mucocelelike lesions are more common than previously
reported and are likely to exhibit indeterminate calcifications on
mammography. Diagnosis is most often made with Mammotome biopsy. A large
number of patients have associated atypia or carcinoma. For patients with
purely benign histologic findings at Mammotome biopsy, optimal management
should be excisional biopsy to exclude associated malignancy.
Keywords: breast • breast cancer • cancer • mammography • radiologic-pathologic correlation
Introduction
Mucocelelike lesions of the breast are unusual tumors that most often have
the mammographic finding of calcifications. Mucocelelike lesion was initially
described in 1986 by Rosen [1]
as a benign lesion characterized by multiple cysts with mucinous material that
has ruptured with the contents extruding into the adjacent stroma. Since the
early 1990s, reports of associated atypical ductal hyperplasia or ductal
carcinoma in situ (DCIS) have appeared in the pathology literature
[2-4].
Few reports in the radiology literature have described the imaging findings
with pathologic correlation. The purpose of our study was to investigate the
imaging findings, correlate them with pathologic results, and determine the
optimal treatment of patients given the tissue-sampling diagnosis of
mucocelelike breast lesion.
Materials and Methods
A review of the surgical pathology database between 1999 and 2002 was
undertaken to find cases of mucocelelike breast lesion. All mammograms were
interpreted by a group of experienced mammographers. Thirty lesions were
identified. The ages of the patients ranged from 29 to 75 years (mean, 52
years). All of the lesions were clinically occult and visible on screening
mammography. The diagnosis was made with imaging-guided large-core biopsy in
22 cases, surgical excision in 7 cases, and fine-needle aspiration biopsy in 1
case. A retrospective review was undertaken of the mammographic findings,
which were correlated with the pathologic results and management
recommendations. All pathologic slides were rereviewed by 1 pathologist. The
cases of patients who did not undergo surgical excision were tracked for a
minimum of 2 years for assessment of stability. The cases of 8 patients who
did not undergo surgical excision were lost to follow-up. Six of these
patients had received a biopsy diagnosis of benign mucocelelike lesion, and 2
had been given the histologic diagnosis of mucocelelike lesion with
atypia.
The histologic diagnosis of mucocelelike lesion was made by percutaneous
imaging-guided large-core biopsy in 22 cases. Seven lesions were subjected to
excisional biopsy. One patient with a hypoechoic breast mass on sonography
underwent sonographically guided fine-needle aspiration biopsy.
Results
Twenty-nine patients with 30 mucocelelike lesions underwent mammography in
a 3-year period (Table 1).
Calcifications of intermediate concern were identified on 25 mammograms. Two
patients had nodules with calcifications of intermediate concern. Three masses
were seen on mammography. At histologic examination, calcifications were
related to all of the lesions in which calcifications had initially been seen
on mammography.
Histologic examination showed that 17 patients had benign mucocelelike
lesions (Figs. 1A,
1B,
1C, and
1D). Percutaneous
imaging-guided large-core biopsy was performed to make the diagnosis for 15
patients. The other 2 patients underwent excisional biopsy. Among the 15
patients with benign mucocelelike tumors diagnosed with percutaneous
imaging-guided large-core biopsy, the final recommendation to 7 patients was 6
months of follow-up and to 8 patients was excisional biopsy. Excisional biopsy
results were available for 4 patients, 3 of whom had benign histologic
findings and 1 of whom had DCIS.
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Fig. 1A —51-year-old woman with screening mammographic finding of round,
well-circumscribed mass containing coarse calcifications due to benign
mucocelelike lesion. Craniocaudal (A) and mediolateral oblique
(B) mammograms show 1.5-cm, round, well-circumscribed mass
(arrows) with coarse calcifications of intermediate concern in upper
outer aspect of breast.
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Fig. 1B —51-year-old woman with screening mammographic finding of round,
well-circumscribed mass containing coarse calcifications due to benign
mucocelelike lesion. Craniocaudal (A) and mediolateral oblique
(B) mammograms show 1.5-cm, round, well-circumscribed mass
(arrows) with coarse calcifications of intermediate concern in upper
outer aspect of breast.
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Fig. 1C —51-year-old woman with screening mammographic finding of round,
well-circumscribed mass containing coarse calcifications due to benign
mucocelelike lesion. Magnification view of calcifications in A and
B.
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Fig. 1D —51-year-old woman with screening mammographic finding of round,
well-circumscribed mass containing coarse calcifications due to benign
mucocelelike lesion. Photomicrograph of histologic specimen shows benign
mucocele of breast with coarse calcification. Large, irregularly shaped,
dilated, mucin-filled spaces (thick arrow) are frequently denuded of
lining epithelium. Mucin within such pool has undergone dystrophic
calcification (thin arrow), which results in coarse calcification on
imaging studies. (H and E, x20)
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On the basis of histologic findings, atypia associated with mucocelelike
lesion was diagnosed in 8 cases. Mammography showed a mass in 2 patients and
calcifications in 6 patients. The diagnosis of mucocelelike lesion with atypia
was made by percutaneous imaging-guided large-core biopsy in 5 patients,
excisional biopsy in 2 patients, and fine-needle aspiration biopsy in 1
patient, who did not undergo subsequent surgical excision. Excisional biopsy
was recommended to 5 patients, 4 of whom underwent the procedure. The
histologic findings were benign in 1 patient and malignant in 3 patients
(Figs. 2A,
2B,
2C,
2D,
2E,
2F, and
2G).
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Fig. 2A —43-year-old woman with screening mammographic finding of coarse and
punctate calcifications distributed regionally in lower central aspect of
breast. Imaging-guided large-core needle biopsy showed mucocelelike lesion
with atypical micropapillary hyperplasia. Finding at excisional biopsy was
micropapillary ductal carcinoma in situ with mucocelelike lesion. Craniocaudal
(A) and mediolateral oblique (B) mammograms show cluster of
coarse punctate calcifications.
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Fig. 2B —43-year-old woman with screening mammographic finding of coarse and
punctate calcifications distributed regionally in lower central aspect of
breast. Imaging-guided large-core needle biopsy showed mucocelelike lesion
with atypical micropapillary hyperplasia. Finding at excisional biopsy was
micropapillary ductal carcinoma in situ with mucocelelike lesion. Craniocaudal
(A) and mediolateral oblique (B) mammograms show cluster of
coarse punctate calcifications.
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Fig. 2C —43-year-old woman with screening mammographic finding of coarse and
punctate calcifications distributed regionally in lower central aspect of
breast. Imaging-guided large-core needle biopsy showed mucocelelike lesion
with atypical micropapillary hyperplasia. Finding at excisional biopsy was
micropapillary ductal carcinoma in situ with mucocelelike lesion. Specimen
radiograph obtained after excisional biopsy of calcifications in A and
B.
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Fig. 2D —43-year-old woman with screening mammographic finding of coarse and
punctate calcifications distributed regionally in lower central aspect of
breast. Imaging-guided large-core needle biopsy showed mucocelelike lesion
with atypical micropapillary hyperplasia. Finding at excisional biopsy was
micropapillary ductal carcinoma in situ with mucocelelike lesion.
Photomicrograph of Mammotome (Ethicon Endo-Surgery) biopsy specimen shows
mucocele of breast with associated atypical duct hyperplasia. Irregularly
shaped, mucin-filled pool (long arrow) is partially lined by atypical
ductal epithelium with intervening cribriform and slitlike spaces (short
arrows). (H and E, x20)
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Fig. 2E —43-year-old woman with screening mammographic finding of coarse and
punctate calcifications distributed regionally in lower central aspect of
breast. Imaging-guided large-core needle biopsy showed mucocelelike lesion
with atypical micropapillary hyperplasia. Finding at excisional biopsy was
micropapillary ductal carcinoma in situ with mucocelelike lesion.
Photomicrograph of needle-localized excisional breast biopsy specimen shows
mucocele with associated ductal carcinoma in situ. Large mucin-filled pool
(long arrow) is present. Three ducts with micropapillary structures
(right short arrow) and rigid epithelial cords and bridges with
intervening cribriform spaces (left short arrow) are evident. (H and
E, x40)
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Fig. 2F —43-year-old woman with screening mammographic finding of coarse and
punctate calcifications distributed regionally in lower central aspect of
breast. Imaging-guided large-core needle biopsy showed mucocelelike lesion
with atypical micropapillary hyperplasia. Finding at excisional biopsy was
micropapillary ductal carcinoma in situ with mucocelelike lesion.
Photomicrograph of needle-localized excisional breast biopsy specimen shows
mucocelelike lesion partially denuded of lining epithelium on left side and
partially lined by highly atypical papillary-type epithelium (arrows)
on right, findings consistent with ductal carcinoma in situ, micropapillary
type. (H and E, x20)
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Fig. 2G —43-year-old woman with screening mammographic finding of coarse and
punctate calcifications distributed regionally in lower central aspect of
breast. Imaging-guided large-core needle biopsy showed mucocelelike lesion
with atypical micropapillary hyperplasia. Finding at excisional biopsy was
micropapillary ductal carcinoma in situ with mucocelelike lesion.
Photomicrograph of same needle-localized excisional breast biopsy specimen as
E and F. Two adjacent ducts contain highly atypical, monotonous
duct cells lining multiple micropapillary structures, some of which in cross
section appear to be floating within duct lumen. (H and E, x100)
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On the basis of histologic findings, mammographically indeterminate
calcification with DCIS associated with mucocelelike lesion was diagnosed in 5
cases. The diagnosis was made by percutaneous imaging-guided large-core biopsy
in 2 patients and excisional biopsy in 3 patients. Three patients underwent
lumpectomy, and the histologic findings confirmed the presence of DCIS.
Discussion
Mucocelelike lesions of the breast are rare benign tumors first described
by Rosen [1] in 1986. Breast
cysts containing mucinous material rupture and discharge secretion into
surrounding breast tissue. The cysts have a flat or cuboidal epithelial lining
with only minimal associated inflammatory reaction. Calcifications may be seen
within mucin-containing cysts. The pathogenesis of these lesions remains
unknown. Excessive mucinous secretions or ductal obstruction may be
responsible. Distention of the cysts associated with incidental trauma to the
breast may result in rupture and subsequent extravasation of the cyst
contents. The similarity in pathologic appearance to mucocele lesions
elsewhere in the body inspired the name given to the breast lesion by
Rosen.
After Rosen [1] described
the lesion as a benign entity, a brief report described a mucocelelike lesion
associated with atypical ductal hyperplasia and ductal carcinoma
[4]. There are infrequent
references in the pathology literature describing cases in which mucocelelike
lesions have been found in association with atypical ductal hyperplasia or
carcinoma. Weaver and associates
[5] studied mucinous carcinoma
and determined that mucin-filled ducts are a common coexisting finding.
Hamele-Bena et al. [6] studied
53 lesions from 49 patients; 25 of the lesions were benign, and 28 were
malignant. Fourteen of 28 patients had mucocelelike lesions associated with
invasive ductal carcinoma, most of which was of the mucinous subtype. The
results of these studies support the perception that mucocelelike lesions
represent a spectrum ranging from totally benign lesions to those associated
with carcinoma.
Correlation of pathologic and imaging findings of mucocelelike tumors is
unusual in the literature. Most previous reports have described small numbers
of patients. Kirk and associates
[7] in 1991 first described the
mammographic findings in 2 patients with mucocelelike lesions. Both patients
had suspicious calcifications. In 1996, Hamele-Bena et al.
[6] described the mammographic
findings in 19 patients with mucocelelike tumors. Fifty percent of the benign
and 82% of the malignant mucocelelike tumors were nonpalpable lesions that
were detected mammographically. The authors determined that malignant
mucocelelike tumors had a higher incidence of coarse calcifications and were
more likely to be detected on mammography than were benign mucocelelike
lesions. Chinyama and Davies
[2] studied 12 mucocelelike
lesions detected on mammography. Eleven cases were clinically occult and were
detected because suspicious calcifications were present on mammography.
However, the authors concluded that there were no consistent features to the
calcifications. Glazebrook and Reynolds
[8] described 5 patients with
mucocelelike lesions. Two patients had a mass, 2 patients had suspicious
microcalcifications, and 1 patient had a mass with suspicious calcifications.
Results at tissue sampling showed 3 of the 5 patients had atypical
hyperplasia. Wylie and Metcalf
[9] reported 20 cases of
mucocelelike lesions, all of which were detected mammographically. Irregular
calcifications imitating ductal carcinoma were evident in 19 patients. One
patient had a complex cystic mass.
The diagnosis of mucocelelike lesion can be challenging at histologic
examination. Fine-needle aspiration may yield mucinous material that is
difficult to differentiate from mucinous carcinoma. In Rosen's
[1] original description, the
findings at aspiration biopsy of a mucocelelike lesion in 2 of 6 patients were
initially believed to represent mucinous carcinoma. However, the diagnosis of
mucinous carcinoma can be made only when a copious number of discohesive
atypical cells are present in aspirate
[3]. When cytologic examination
shows the presence of only a few bland cells within a mucinous background, the
diagnosis of mucinous carcinoma cannot be made. Mucocelelike lesions may have
a relatively benign and paucicellular appearance at fine-needle aspiration
biopsy. Only at excision can the presence of coexistent carcinoma be confirmed
or ruled out [10,
11].
Most mucocelelike lesions manifest as indeterminate calcifications on
mammography, and percutaneous imaging-guided large-core biopsy is performed
for diagnosis. When a mass is evident on sonography, core needle biopsy may be
used for diagnosis. However, differentiation between mucocelelike tumor and
mucinous carcinoma can be difficult or impossible in core biopsy specimens in
which the material is fragmented.
The current pathologic recommendation is that the presence of a
mucocelelike lesion at percutaneous imaging-guided large-core biopsy is an
indication for surgical excision
[12,
13]. Our experience suggests
that there is not uniform compliance with the current recommendation in the
literature. The presence of benign elements in mucocelelike tumors without
atypia did not always result in a recommendation for surgical excision at our
institution. When atypia is associated with mucocelelike tumors, there is
closer to uniform agreement with the need for subsequent surgical
excision.
Mucocelelike lesions of the breast probably are a pathologic continuum of
mucinous DCIS and mucinous carcinoma. There is a possibility that these
entities can coexist within 1 lesion. Therefore the current recommendation is
excisional biopsy of lesions with features suggestive of benign mucocelelike
lesion at fine-needle aspiration biopsy or percutaneous imaging-guided
large-core biopsy. The results of our study indicate that there is no
concordance among pathologists in the recommendation that follows a benign
diagnosis of mucocelelike tumor at percutaneous imaging-guided large-core
biopsy. Although in our study only a small number of lesions initially
reported were subjected to subsequent excisional biopsy, the fact that 25% of
patients had DCIS supports the current pathologic recommendation for
excisional biopsy. When atypia was evident in the pathologic specimen,
excisional biopsy was uniformly recommended by the pathologist. In our series,
75% of this group of patients were found to have DCIS at excisional biopsy.
This finding suggests a higher incidence of underestimates of atypical ductal
hyperplasia in patients with mucocelelike lesions compared with those without
mucocelelike lesions at percutaneous imaging-guided large-core biopsy
[14].
Mucocelelike breast lesions are unusual. To our knowledge, large series of
cases detected on mammography and diagnosed with percutaneous imaging-guided
large-core biopsy have not been reported. Our study differs from that of
Glazebrook and Reynolds [8] in
that the most common finding on mammography in our study was calcifications of
intermediate concern. In addition, the average patient age in our study was
postmenopausal. Our study also showed a lack of uniform recommendation by the
pathologist for excisional biopsy after benign mucocele was diagnosed at
percutaneous imaging-guided large-core biopsy. This finding should make
mammographers performing these procedures aware of the appropriate
recommendation in the absence of a suggestion within the pathology report. In
summary, mucocelelike breast tumors are uncommon but appear to be increasing
in frequency as a diagnosis at percutaneous imaging-guided large-core biopsy.
The appropriate recommendation is for excisional biopsy, even of lesions
classified as benign at histologic examination.
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Abstract
Introduction
