Scrotal Involvement in Gist: a Case Report of Testicular Metastasis and Literature Review

Introduction: Gastrointestinal stromal tumors (GISTs) are mesenchymal tumors of the digestive tract originating from interstitial Cajal cells. Mutations in the KIT, PDGFRA, and occasionally BRAF genes are the main drivers of oncogenesis (1). The stomach is the most common primary location, followed by the small intestine. Metastatic GISTs most frequently involve the liver and peritoneum. However, scrotal involvement is exceedingly rare. Case Presentation: A 63-year-old man was diagnosed in 2012 with ileal GIST and peritoneal carcinomatosis. He underwent ileal resection and received Imatinib (400 mg daily) until 2018. Following disease progression in 2020, Imatinib was reintroduced at the same dose, resulting in a complete response. The patient was subsequently lost to follow-up until 2022, when he presented with abdominal and scrotal swelling. A testicular ultrasound revealed a large mass in the right scrotum, and a CT scan showed extensive intraperitoneal masses and multiple liver nodules. A right orchiectomy was performed. Histological examination identified a malignant spindle cell mesenchymal tumor with sarcomatous involvement of the testicular parenchyma without direct invasion. Postoperatively, the patient resumed Imatinib (400 mg daily), later increased to 800 mg due to disease progression in the liver and peritoneal masses in July 2023. By January 2024, further liver progression led to the initiation of Sunitinib. No additional scrotal metastases were noted.