15-year ultra-late presentation of bifocal hepatic metastasis from gastrointestinal stromal tumor: a case report.

Gastrointestinal stromal tumors (GISTs) are rare mesenchymal neoplasms of the gastrointestinal tract, and ultra-late recurrence (defined as recurrence occurring ≥10 years postoperatively) is particularly uncommon, especially among patients with inadequate adjuvant targeted therapy. Herein, we report a 64-year-old male patient with jejunal GIST who developed bifocal hepatic metastases 15 years after primary tumor resection. Postoperatively, the patient received only 1 year of adjuvant imatinib (400 mg/day) and remained disease-free for the subsequent 14 years, until liver lesions were incidentally identified during a routine physical examination. Comprehensive imaging studies confirmed two lesions in liver segments S4 (43 mm) and S7 (17 mm), which were consistent with metastatic characteristics. The patient subsequently underwent partial hepatectomy of segments S4 and S7 with intraoperative ultrasound-guided wire localization, achieving R0 resection. Pathological examination of both metastatic lesions revealed spindle cell proliferation, with immunohistochemical staining positive for CD117 (+) and Dog-1 (+), consistent with the typical phenotypic profile of GIST, thus confirming their GIST origin. At the 6-month postoperative follow-up, the patient remained asymptomatic, with no radiological or clinical evidence of tumor recurrence. This case is clinically distinctive owing to its ultra-long recurrence interval and synchronous bifocal hepatic metastasis, thereby offering valuable insights into the long-term natural course of GISTs in the setting of inadequate adjuvant tyrosine kinase inhibitor (TKI) therapy. Furthermore, it underscores the necessity of long-term postoperative surveillance for patients with GIST and highlights the potential role of comprehensive genetic testing in guiding individualized treatment decisions.