906
Chapter 33
Occult breast carcinoma presenting as an ALNmetastasis
is exceedingly unusual in men.
158–160
In some cases, axillary
metastases from a nonmammary primary, such as carci
noma of the lung, have been documented in men, generally
after treatment of the pulmonary primary.
145,161,162
There is
insufficient experience with this presentation of male breast
carcinoma to compare with female patients.
Gross Pathology
The frequency with which a primary tumor is detected
pathologically in the ipsilateral breast varies from 55%
133
to
82%.
130,138
In most series, the proportion with a documented
primary was about 75%.
129,131,133,135,140
Although not clinically
palpable, the majority of carcinomas were found upon gross
examination of a mastectomy or excisional biopsy specimen
(Fig. 33.10). Rarely, the breast has contained two separate,
grossly evident invasive primary carcinomas, each of which
may be accompanied by an
in situ
component.
135,152
The le
sions have measured up to 6.5 cm,
130,134,135
but most were 1
to 2 cm or less in diameter. In one series, the median size
was 1.9 cm and the mean 1.5 cm, with 82% classified as T1,
14% as T2, and 4% as T3
.
135
In a review of eight retrospective
studies published in 2010, de Bresser et al.
149
reported that le
sions detected by MRI measured between 5mm and 3cm and
that the pathologically measured size of these lesions ranged
from 1 mm to 5 cm. Smaller tumors were often discrete, with
a stellate or circumscribed contour, but those larger than 2
cm more often had ill-defined margins and tended to blend
grossly with the surrounding breast tissue. The majority of
the primary lesions occur in the upper outer quadrant and
less often in other quadrants.
131,133–135,137
The occult primary
tumor has rarely been detected in the axillary tail.
151
About 30% of the clinically occult primary carcinomas
are not evident when a mastectomy specimen is examined
grossly. These lesions are found by taking multiple random
sections of breast tissue that appears grossly normal. Conse
quently, sampling should not be limited to grossly abnormal
parenchyma. Radiography of breast biopsies and mastecto
mies has not been helpful for locating the primary and can
not be relied upon for guidance in the sampling of tissue for
histologic study. This is not unexpected in view of the lack of
success with clinical mammography in these patients.
The likelihood of finding a primary lesion in the breast is
related to the thoroughness with which the available tissue
has been studied. In some cases, the primary tumor remains
undetected because a breast biopsy, or mastectomy, or both,
was not performed. Despite careful and extensive gross and
microscopic examination of a mastectomy, there are rare
instances in which no primary is found. Patients not proven
to have a primary breast carcinoma or a primary tumor at
another site have a similar age distribution, similar lymph
node findings, and comparable survival results as those with
a pathologically demonstrated clinically occult breast carci
noma. In one series, none of the 12 patients without a docu
mented primary breast lesion were later shown to have an
extramammary primary.
133
Axillary Lymph Nodes
Among patients subjected to axillary dissection, the number
of lymph nodes found to be involved by metastatic carci
noma varies from one to as many as 65.
130,131,135,139
When nu
merous lymph nodes are involved, they rarely form a matted
mass with extranodal extension. In one series, one-half of
the 40 patients had one to three involved lymph nodes (1 to
3 positive), including 13 patients whose only positive lymph
node was the one removed for diagnosis (Fig. 33.11). Among
15 women with carcinoma, in four or more lymph nodes the
median number involved was 11.
FIG. 33.11.
Occult carcinoma.
This solitary enlarged ALN
containing metastatic papillary carcinoma is greater than
2 cm in diameter. No primary tumor was detected in either
breast by clinical palpation or on radiological evaluation.
The metastatic carcinoma in the lymph node was ER (
+
),
CK7 (
+
), CK20 (−), WT-1 (
+
), and PAX8 (
+
). A 3.0-cm ovar-
ian papillary serous carcinoma was subsequently resected.
FIG. 33.10.
Occult carcinoma, mastectomy.
The
arrow
indicates a small IDC that was not palpable clinically.
A bisected ALN with metastatic carcinoma is shown in the
lower right
portion of the specimen.
