2 Case Reports in Medicine Figure 1: Gastric biopsy. Inﬁltrating tumor cells (arrow) involving gastric antrum wall (hematoxylin and eosin). Original magniﬁca- tion ×200. Figure 3: Chest wall lesion. Inﬁltrating estrogen receptor, ER- positive tumor cells amongst ﬁbrous septa consistent with metastatic breast carcinoma. Original magniﬁcation ×100. Figure 2: Gastric biopsy. Numerous cytokeratin 7, CK7-positive tumor cells inﬁltrating gastric wall. Original magniﬁcation ×200. carcinoma consistent with a breast primary. Estrogen recep- tor was strongly positive and progesterone receptor was negative. HER2 was negative by FISH. She oﬀered no breast complaints at the time of diagnosis. Clinical examination of the breasts and axillae was normal. Screening mammograms performed previously showed heterogeneously dense nodu- lar parenchyma bilaterally. Minimal architectural distortion was present in the superior portion of the left breast but this was previously noted and felt to be benign. Family history was remarkable for a maternal aunt and a paternal aunt with postmenopausal breast carcinoma. Given her unusual pathology, all of her prior pathology was sent to our institution for review. The previously resected colon polyp and chest wall lesion were reevaluated and found to be consistent with metastatic breast carcinoma. She underwent a bilateral breast MRI examination, which showed no worrisome areas of focal enhancement. She was then started on with hormonal therapy with an aromatase inhibitor. 3. Pathological Findings The stomach biopsy specimen showed metastatic carcinoma consistent with breast primary. Immunohistochemical stains CK7, CK20, CD45, CDX2, estrogen receptor (ER), pro- gesterone receptor (PR), and HER2 were performed. The neoplastic cells were ER positive (>95% nuclear staining), PR weakly positive (10% nuclear staining), and CK7 positive. Tumor stainings for HER2, CK20, CD45, and CDX2 were negative. The pattern of tumor inﬁltration, morphology and immunohistochemical proﬁles were consistent with lobular breast carcinoma. The stomach lesion exhibited a linitus plastica appearance. The chest wall lesion was also consistent with metastatic breast carcinoma which was ER positive, PR weakly positive, and equivocal for HER2 (score 2+) with negative HER2 gene ampliﬁcation by FISH. 4. Discussion Occult breast carcinoma may rarely present as axillary metas- tasis [2]; however, presentation as gastrointestinal metastasis has never been described. Metastases from gastrointestinal system have been reported after a previous diagnosis of breast carcinoma within a period of months to years between the original diagnosis of breast cancer and recurrence in the gastrointestinal tract [1, 7]. Symptoms of gastrointestinal metastases can be very nonspeciﬁc in their presentation. In this case report, the gastrointestinal metastasis was an incidental ﬁnding, and retrospective review of histology revealed that this was of breast origin. The metastatic patterns of lobular and ductal carcinoma have been reported to diﬀer considerably. Metastatic breast carcinomas of ductal origin usually present with hepatic, lung, brain, and bone metastases whereas metastatic lobular carcinoma is noted to spread to gastrointestinal, gyneco- logical, and peritoneal structures [8]. Autopsy series report the distribution of gastrointestinal metastases as follows: