Late Recurrence Matters: Delayed Hepatic Metastasis After Rectal Neuroendocrine Tumor

Rectal neuroendocrine tumors (NETs) are rare, typically indolent neoplasms arising from enterochromaffin cells that may recur locally or distantly after long disease-free intervals. We report a case of robotic partial hepatectomy for delayed hepatic metastasis from a rectal NET. Methods: A 68-year-old woman was referred for evaluation of a liver lesion suspicious for metastatic rectal NET. Ten years earlier, a 4 mm rectal NET had been identified on screening colonoscopy and treated with endoscopic mucosal resection, with no residual malignancy. Surveillance endoscopy showed no recurrence. Ten years after diagnosis, CT imaging for an unrelated issue revealed a 4.8 × 4.3 cm lesion in segment III of the liver. MRI demonstrated a 5.2 × 5.5 cm mildly T2 hyperintense mass with heterogeneous low-level enhancement and marked restricted diffusion, concerning for metastasis. After discussion, the patient underwent robotic partial hepatectomy without complication and was discharged on postoperative day one. Pathology revealed a 6.2 cm metastatic carcinoid tumor with negative margins and lymphovascular invasion. Mitotic index was 3 per 10 high-power fields and Ki-67 was 4%, consistent with an intermediate-grade tumor. At 16 months postoperatively, she remains disease-free. Conclusion: Isolated hepatic recurrence of rectal NET after a prolonged disease-free interval is uncommon. Although international societies provide surveillance recommendations after rectal NET resection, there remains no clear consensus on the optimal duration of surveillance for patients at higher risk of recurrence or with incomplete initial pathologic data. A personalized, multidisciplinary surveillance strategy should therefore be considered in such patient.