Abstract
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.

Key words: Gastrointestinal stromal tumor, desmoid tumor, mesenchymal neoplasm, retroperitoneal mass.