Diagnostic and Therapeutic Approach to Metachronous Splenic Metastases of Gastric Adenocarcinoma: Case Report and Literature Review

<b>Background and Clinical Significance</b>: In gastric cancer, splenic metastases are found in less than 7% of cases and are usually associated with other systemic secondary determinations; much more rarely, they represent the sole secondary determination of the malignant disease. <b>Case presentation</b>: In this paper, we present the case of a 64-year-old patient who underwent curative surgery for gastric adenocarcinoma 10 months ago and, during oncological monitoring, was diagnosed with a splenic tumor formation with intense metabolic activity on PET-CT examination, raising suspicion of splenic metastases. The medical team observed an increase in carcinoembryonic antigen (CEA), carbohydrate antigen (CA) 19-9, and Cluster of Differentiation (CD) 276 values, along with a slight decrease in Dickkopf Related Protein 3 (DKK 3). Considering that the spleen was the only site of secondary localization of the malignant disease, the patient underwent laparoscopic splenectomy with histopathological confirmation of the presence of gastric adenocarcinoma. There are no signs of loco-regional or distant recurrence 15 months postoperatively. In patients with radical excision of gastric cancer who present only with splenic metastases, splenectomy is indicated and is associated with good disease-free survival. If other secondary manifestations of malignant gastric disease are identified or suspected, chemotherapy treatment and the wait-and-see approach are recommended, as the patient does not have a real benefit from splenectomy. Until now, there is no standard protocol for the diagnostic and therapeutic management of patients with gastric cancer and metachronous splenic metastases; thus, the development of a decision-making scheme for these situations is necessary. <b>Conclusions</b>: The multidisciplinary approach, including the tumor board and an infectious disease specialist, are important steps in the effective management of these cases. The role of new biological markers such as CD 276 and DKK 3 for assessing the progression of malignant disease could constitute a new direction for research.