Breast Metastasis of Gastric Signet Ring Cell Carcinoma: A Case Report and Literature Review

Gastric cancer metastatic to the breast: A case report

BACKGROUND

Metastatic breast cancer originating in the gastrointestinal tract is a rare occurrence. The limited number of cases has resulted in incomplete understanding of the disease, making it challenging to differentiate from primary breast cancer. While clinical history and immunohistochemical studies can aid in distinguishing between the two, the management principles and pathogenesis of gastrointestinal metastatic breast cancer remain controversial. The scarcity of data has hampered comprehensive knowledge. Our objective is to shed light on this rare disease through our case study.

CASE SUMMARY

Here, we report a case of breast metastasis from gastric cancer in a 43-year-old woman. This patient was admitted to our hospital with complaints of discomfort in the upper and middle abdomen persisting for two months, as well as black stools for over ten days. She underwent radical distal gastrectomy for gastric cancer, followed by postoperative chemotherapy. Three years later, the patient developed bilateral breast nodules. Imaging studies indicated a high probability of malignancy. She subsequently underwent a right modified radical mastectomy and excision of a left breast mass. Postoperative pathology revealed the right breast tumor was consistent with primary gastric cancer.

CONCLUSION

We present a case of breast metastasis from gastric cancer to contribute to the limited foundation of research into this rare disease.

Unusual Metastasis of Gastric Signet Ring Cell Carcinoma to the Breast: A Case Report of a Young Moroccan Patient

Although gastric cancer is known to be an aggressive tumor that can spread throughout the body, breast metastases are uncommon. This entity is rarely reported in the literature, with an estimated incidence of 0.5 to 1.3%. We report a case of a rare association between a gastric subtype of signet ring cell carcinoma and metastasis to the breast. This uncommon situation is only documented through case reports. Most breast metastases have been detected after diagnosis of primary gastric cancer, during the first year. Several risk factors have been suggested to explain the aggressive behavior of these tumors, which correlates with very poor prognosis and short survival. We report the case of a 22-year-old female patient presenting with widespread metastatic gastric signet ring cell carcinoma with an unusual secondary site in the breast. The diagnosis was confirmed by immunohistochemistry (IHC) and radiology, and the patient was treated with palliative chemotherapy in accordance with the decision of the multidisciplinary tumor board.

Invasive lobular carcinoma with extracellular mucin (ILCEM): clinicopathologic and molecular characterization of a rare entity

Invasive lobular carcinoma with extracellular mucin (ILCEM) is a rare histologic subtype of breast cancer. Little is known about the pathologic or genomic signatures that distinguish ILCEM from classic invasive lobular carcinoma (ILC) or mucinous carcinoma. We studied 17 breast cancers with lobular morphology and extracellular mucin. Thirteen tumors with sufficient tissue for DNA extraction were analyzed by a next generation sequencing (NGS) assay that interrogates 447 genes for mutations and copy number variations (CNVs). Median patient age was 66 yrs (range: 31-77 yrs). Sixteen patients presented with masses, 7 of which were >2 cm. Seven patients had lymph node metastases. The cases of ILCEM were moderately (n = 13) or poorly differentiated (n = 4), frequently exhibiting variant morphology that has not been previously described or emphasized, including grade 3 nuclei (n = 11), diffuse signet ring cells (n = 10), solid growth (n = 4), tumor necrosis (n = 3) or apocrine features (n = 2). All tumors showed absent or reduced membranous E-cadherin expression. Concurrent lobular carcinoma in situ (LCIS) was seen in 11/17 cases, 1 of which was a striking example of signet ring cell LCIS with extracellular mucin. Receptor profiles were ER+/HER2- (n = 15) and ER+/HER2+ (n = 2). With a median follow-up of 83.5 months (range: 3-171 months) in 12 patients with available information, 8 patients had recurrences resulting in 4 cancer-related deaths. The most common CNVs were 16q loss (n = 11) and 1q gain (n = 9). CDH1 gene-level alterations were detected in all but one case, including frameshift (n = 7), nonsense (n = 2), and donor splice site (n = 1) mutations and indels (n = 2). Recurrent mutations were also seen in PIK3CA (n = 3), POLQ (n = 3), TP53 (n = 3), ERBB3 (n = 3), ERBB2 (n = 2), and RUNX1 (n = 2). Genes with recurrent amplifications included GATA3 (n = 4), FOXA1 (n = 3), CCND1 (n = 2). Our data highlights ILCEM as a distinct variant of ILC that often presents with higher-grade and variant morphologic features and is associated with an aggressive clinical course. NGS data support an overall lobular-type molecular profile and reveal potentially targetable alterations in a subset of cases with recurrence.