Case Report: Renal metastasis of a gastric gastrointestinal stromal tumor mimicking a primary renal carcinoma.

Introduction: Gastrointestinal stromal tumors (GISTs), mesenchymal neoplasms of the gastrointestinal tract, are prone to recurrence and metastasis. Despite improvements in prognosis with targeted treatments, such as imatinib, some patients develop metastatic GIST. Renal involvement in GIST is uncommon, and data on the diagnosis and treatment of GIST with renal metastasis remain limited. In this report, we describe the diagnostic and therapeutic regimen used for a patient with renal metastasis from GIST, providing an important reference for clinicians. Case presentation: A 52-year-old man underwent resection of a gastric GIST 5 years previously and had received adjuvant imatinib therapy for 2 years. A radical nephrectomy was performed, and histopathological analysis confirmed metastatic GIST. Although the patient resumed imatinib therapy post-surgery, follow-up imaging 22 months later revealed multiple metastases in the retroperitoneum and abdominal cavity. Conclusion: Renal metastasis from GIST is highly aggressive. Although surgical resection offers considerable palliation and may prolong survival, survival is generally dependent on sustained multimodal therapy and follow-up. Early detection and management of recurrent or metastatic lesions are imperative to optimize long-term outcomes.