Prognosis of duodenal gangliocytic paraganglioma with lymph node metastasis: is follow-up >5 years required?

Gangliocytic paragangliomas (GP) are rare tumors encountered exclusively in the second portion of the duodenum. Duodenal gangliocytic paraganglioma (DGP) belongs to a subclass of neuroendocrine neoplasms, characterized with unique histologic features of carcinoid tumor, paraganglioma and ganglioneuromas. According to the recent World Health Organization classification of gastrointestinal neuroendocrine tumors (NETs), there is a debate to classify them either as low-grade NETs or as an independent entity. There are a few reports of regional lymph node (LN) metastasis that could argue DGP as a true neoplasm. However, majority of them had a benign course, raising the question of whether long-term follow-up is required. We report a case of a retroperitoneal LN involvement by metastatic GP and additionally performed a systematic review of the literature to determine the optimal follow-up, since no guidelines exist for this rare entity.