[Gastric signet ring cell adenocarcinoma metastatic to the breast. Systematic review of the literature, regarding a case].

Objectives: To determine the general state of scientific evidence published in the last 20 years on gastric signet ring cell (SRC) adenocarcinoma metastatic to the breast, and present a case. Material and methods: The case of a patient who attended a high-complexity reference institution in Bogotá for a breast metastasis from a gastric SRC adenocarcinoma is reported. A Systematic Review of the literature was carried out, including cohort studies, reports and case series of patients with gastric SRC adenocarcinoma metastatic to the breast, which will present information on the epidemiology, clinical, radiological and histopathological characteristics, and the treatment and prognostic of this disease. Results: There were identified 363 references, twenty-six of which met the eligibility criteria. Gastric SRC adenocarcinoma metastatic to the breast predominated in the Asian continent (75.9%). The mean age at presentation was 42.5 years. In 62% (n=18) of cases this condition manifested clinically as a breast mass. From a radiological point of view, the majority of breast lesions presented as one or several nodules with suspicious characteristics (55.2%; n=16). In the biopsy of breast lesions, positivity for cytokeratin 7 and cytokeratin 20 occurred in 41.4% (n=12) and 37.9% (n=11) of cases, respectively. Only nine patients (31%) underwent any type of breast surgery. There is a lack of information on the treatment and prognosis of gastric SRC adenocarcinoma metastatic to the breast. Conclusions: The frequency of cases of gastric SRC adenocarcinoma metastatic to the breast published in the last 20 years is low. The general practitioner and the gynecologist could be the first medical professionals to face this rare condition, so knowing it and suspecting it is essential, especially if we take into account that the median overall survival of these patients is low.