Small Intestinal Carcinoma

P1, N=30, Active, not recruiting, City of Hope Medical Center | Trial completion date: Jun 2026 --> May 2027

Multivariate analysis showed that a distance from the lesion center to the ligament of Treitz of 85 mg/L (OR=6.168, 95%CI: 1.514-25.128, P=0.007) were independent risk factors for PPOI after segmental jejunal resection. Patients undergoing proximal jejunal resection, defined as a distance from the lesion center to the ligament of Treitz of <30 cm, as well as those with postoperative hypokalemia and elevated C-reactive protein levels, are at a higher risk of developing PPOI.

P=N/A, N=36, Recruiting, Dartmouth-Hitchcock Medical Center | Trial completion date: Dec 2026 --> Dec 2027 | Trial primary completion date: Sep 2026 --> Sep 2027

P2, N=54, Recruiting, Yale University | Initiation date: Mar 2026 --> Jun 2026

We present a renal transplant recipient with metastatic small bowel adenocarcinoma harboring a POLE mutation who was treated with pembrolizumab and achieved a complete metabolic response on PET-CT with negative circulating tumor DNA. This case suggests that immune checkpoint inhibitors may be considered in carefully selected transplant recipients with high tumor mutational burden, though risks remain.

Gross examination of the colectomy specimen revealed more than 20 large polyps measuring up to 4 cm. Histopathological analysis demonstrated colonic serrated polyposis without evidence of invasive malignancy, wall infiltration, or lymph node involvement, with clear surgical margins.

The patient recovered uneventfully with resolution of bleeding and normalization of hemoglobin. This case highlights the importance of considering small bowel GIST in unexplained melena and severe anemia and demonstrates the curative potential of timely surgical resection in localized low-risk disease.

P=N/A, N=750, Active, not recruiting, M.D. Anderson Cancer Center | Trial completion date: Jan 2026 --> Jan 2028 | Trial primary completion date: Jan 2026 --> Jan 2028

This case highlights an unusual presentation of a rare malignancy in a duodenal neuroendocrine tumor identified during evaluation of iron deficiency anemia. It emphasizes the importance of comprehensive endoscopic assessment and targeted biopsy in patients with unexplained anemia, including consideration of uncommon gastrointestinal neoplasms.

This case represents a rare duodenal MGT confirmed by histopathology and immunohistochemistry, with novel FOXP1 and KDM5A mutations identified for the first time. These findings broaden the molecular spectrum of MGT and highlight the importance of integrating molecular profiling into the diagnosis and management of rare tumors, while surgical resection remains the cornerstone of therapy.

The postoperative course was complicated by sepsis, respiratory failure, and prolonged ileus. This case highlights the importance of considering primary gastrointestinal lymphoma in the differential diagnosis of bowel perforation and acute surgical abdomen, particularly in elderly patients presenting emergently.

This case underscores the role of immunotherapy in POLE-mutated tumors regardless of the site of origin and highlights the potential usefulness of molecular profiling in rare malignancies. In line with the agnostic approach used for microsatellite instability, molecular-driven clinical trials should be prioritized over histology-based studies to optimize treatment strategies for these orphan diseases.