A case of paraganglioma that mimicked a duodenal tumor

Abstract

Purpose: To report a case of paraganglioma that mimicked a duodenal tumor. Case report: A woman in her 70’s underwent a coronary CT examination whereupon a paraduodenal tumor was discovered. A dedicated contrast-enhanced abdominal CT demonstrated a well-defined mass that partially abutted the duodenum. The tumor showed avid contrast enhancement in the arterial phase; the contrast enhancement lasted until the venous phase. MRI showed cysts within the tumor, and the T2-weighted image showed heterogeneous hyperintensity. There were dot-like and linear hypointense regions, suggesting a signal void due to rapid flow in the tumor. As a hypervascular tumor containing areas of cystic degeneration, retroperitoneal paraganglioma was a possible differential diagnosis. ¹²³I-MIBG scintigraphy showed significant uptake at the site of the tumor. After surgery, the histopathological diagnosis was paraganglioma, consistent with the clinical diagnosis. Discussion: Avid contrast enhancement in the arterial phase and cystic degeneration in the tumor are typical features of paraganglioma, duodenal gastrointestinal stromal tumors, and pancreatic neuroendocrine tumors. Sympathetic ganglia exist in the periarterial space of the renal artery, and consequently, paragangliomas can occur in this area. Paraganglioma should be included in the list of differential diagnoses for paraduodenal tumors. Conclusion: Paraganglioma should be included in the list of differential diagnoses for a hypervascular retroperitoneal tumor near the duodenum that exhibits a contrast enhancement in the arterial phase. Discovery of endocrine abnormality may assist diagnosis, and ¹²³I-MIBG scintigraphy is necessary to reach a diagnosis of paraganglioma.