Beyond the Expectation: Pembrolizumab-Associated Tumor Lysis Syndrome in Metastatic Gastric Adenocarcinoma.

Tumor lysis syndrome (TLS) emerges as a critical oncological emergency, a consequence of the body's struggle to manage the intense cellular turnover and release of cytotoxins induced by treatments such as chemotherapy, radiation, targeted immune therapy, or hormonal therapy. While commonly associated with hematological malignancies, the heightened risk also extends to advanced-stage solid tumors and instances of liver metastasis. Although TLS is a rare occurrence in gastric adenocarcinoma, reported cases are usually linked to the initiation of chemotherapy. Remarkably, the incidence of TLS following the commencement of pembrolizumab in gastric adenocarcinoma remains undocumented in the existing literature. In this context, we present a compelling case involving a 73-year-old gentleman diagnosed with advanced-stage metastatic gastric adenocarcinoma. Strikingly, the patient developed TLS subsequent to the initiation of pembrolizumab (Keytruda®). This unique scenario not only accentuates the atypical manifestation of TLS in the context of gastric adenocarcinoma but also underscores the need for heightened awareness and exploration of potential complications associated with immunotherapeutic agents in solid tumor settings. The detailed analysis of this case contributes valuable insights that may prove instrumental in refining our understanding of the intricate interplay between immunotherapy and tumor lysis syndrome in the specific landscape of gastric adenocarcinoma.