Post-operative desmoid tumors in GIST patients: Clinical patterns, imaging features and management implications

Objective: To analyze the co-occurrence of intra-abdominal desmoid tumors following GIST surgery and establish guidelines for appropriate diagnostic and therapeutic approaches. Methodology: We conducted a comprehensive literature review of sporadic intra-abdominal desmoid tumors occurring after initial GIST excision. We analyzed 26 cases from 17 published reports, including our case of a 43-year-old male who developed a retroperitoneal lesion after duodenal GIST surgery. Clinical presentations, radiological findings, pathological characteristics, treatments, and outcomes were evaluated. Results: The mean age of occurrence was 56.2±4.0 years, with 76% of cases in males (19/25). Desmoid tumors developed at a mean interval of 27.3±6.8 months post-GIST surgery. High and intermediate-risk GIST cases were more prevalent (11:4). Most desmoid tumors involved the omentum and mesentery near surgical sites, with retroperitoneal involvement in only two cases. PET-CT showed lower metabolic activity in desmoid tumors (mean SUVmax: 3.6 ± 2.0) compared to GIST recurrence. Conclusion: In post-GIST surgery surveillance, new solitary lesions should raise suspicion for desmoid tumors in the differential diagnosis, despite radiological similarities to GIST recurrence. This distinction is critical for appropriate management strategies.