Breast adenocarcinoma is the most common tumor of
adult women in most part of the world. However, metastatic
involvement of the breast by nonmammary malignancy
is extremely rare. It has been reported that metastatic
tumors account for approximately 1.3-2.7% of all
malignant mammary tumors. Sporadic cases do occur,
until now, the largest series were published by Georgiannos
et al.[
1]. In this report, the files of the histopathology
department of the Royal London Hospital were reviewed,
including all surgical and postmortem materials during
the period 1907-1999. It was found that 450 malignancies
(3.2%) had involvement of the breast by secondary
tumors, most of which (390 malignancies; 86.7%) were
considered metastases from the contralateral breast, it was
also found that the remaining 60 malignancies (13.3% of
secondary malignancies and 0.43% of total breast malignancies)
were nonmammary metastases. Involvement of
the breast by hematological malignancies, such as lymphoma
and leukemia, were becoming relatively more
common. Only 4 of 60 patients had adenocarcinoma of
the stomach of the signet ring type[
1].
Primary SRCC has been described in many adenocarcinomas;
particularly stomach, urinary bladder, urethral, colorectal, mediastinal and lung tumors. The incidence of
SRCC of the stomach was reported to vary from 3.4%
in Japan to 39% in western countries[2,3]. SRCC of the
stomach can be detected at an early stage. Although it
rarely involves the entire stomach and seldom invades
the gastric wall, peritoneal metastasis often occurs and
the prognosis is poor once gastric SRCC has become advanced.
Consequently, the most common metastatic sites
are peritoneum and regional lymph nodes and the other
less metastatic site is liver for advanced gastric SRCC[4].
Gastric SRCC occurs more often in women and younger
age groups. Our patients were women but they were in
an older age group; 63 and 65 years old. Prior to the resection
of the primary gastric SRCC we should use diagnostic
procedures for gastro-endoscopic and pathological
examination. Because the lesions of early gastric SRCC
tend to be depressed, gastroendoscopic detection often
uses contrast with indigo carmine solution. Moreover, the
carcinoma cells are detected easily in biopsy specimens
because of their typical enriched intra-cytoplasmic mucin
and peripheral compressed nuclei[4].
Antonioli and Goldman[5] reported that 29% of patients
with gastric carcinoma had signet ring carcinoma
subtype. Metastasis to breast from gastric carcinoma is
extremely rare. In the literature only approximately 300
cases of tumor metastases to the breast have been described.
Metastasis arising from the gastrointestinal tract
is rare and relatively few cases have been reported. One
of these gastric SRCC cases, which was a metastasis to
breast and clinically presented as an inflammatory carcinoma
was published in 1993. The clinical manifestation
was highly suggestive of inflammatory carcinoma with
red and edematous skin[6]. Such clinical findings were
also observed similarly in one of our cases. However; in
patients who had breast masses diagnosed as SRCC, primary
breast SRCC should be distinguished from gastric
SRCC metastasis.
Clinically, metastatic lesions are not fully distinct
from primary tumors. Thus differentiating primarily from
metastatic breast carcinoma is important for rational and optimum therapy and avoidance of unnecessary radical
surgery. Some clinical findings can help us such as,
secondary breast cancers being more likely to be freely
mobile, round, solitary and free of pain, discharge or skin
changes[7]. However, secondary breast cancers may have
multiple or diffuse involvement. Secondary breast cancers
resemble benign lesions, although imaging studies
may not demonstrate a mass in mammographic scanning[8]. Kwak et al.[9] considered that, the patients who had
breast mass might be SRCC in the breast, even though
imaging studies haven't indicated any positive findings
for SRCC. To distinguish primary breast cancer from
SRCC metastasis; immunohistochemical staining for ER
or PR are helpful. ER are often present in breast cancers,
but more than 20% of primary gastric cancers also have
evidence of ER[10]. In immunohistochemical studies
for metastasis from stomach adenocarcinoma and SRCC,
CEA and cytokeratins 20 and 7 are often positive, also
ER and PR are negative. The combination of cytokeratin
20 and CEA positive staining in conjunction with negative
ER staining strongly supports a diagnosis consistent
with a primary gastrointestinal tumor rather than a primary
breast carcinoma[11]. In our both cases, ER and
PR were negative while CEA was positive. There were
not any positive findings for primary breast carcinoma in
imaging studies.
In conclusion; secondary tumors to the breast are rare,
and were reported to account for only approximately 2%
of all malignant breast cancers. Clinically, metastatic lesions
are not distinct from primary tumors. Thus differentiating
primary tumor from metastatic breast carcinoma
is important for rational and optimum therapy and avoidance
of unnecessary radical surgery. Patients who have
breast masses and stomach complaints or gastric carcinoma
without any finding in imaging studies, and who have
CK20 and CEA positivity with ER, PR and CK7 negativity
in immunohistochemical studies, don't have primary
breast carcinoma. These patients should be evaluated for
stomach ring cell carcinoma.
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