A rare serious case of retroperitoneal paraganglioma misdiagnosed as duodenal gastrointestinal stromal tumor: a case report

BACKGROUND: Pheochromocytoma (PCC) and Paraganglioma (PGL) are rare neuroendocrine neoplasms. These tumors harbour disastrous consequences during surgery due to catecholamine hypersecretion if they are undiagnosed or prepared inadequately preoperatively. CASE PRESENTATION: A 41- year- old lady presented with mild left flank discomfort. She had experienced recurrent anxiety attacks accompanied by palpitations and headache which were managed previously as panic attacks. Radiologic investigations showed a retroperitoneal mass that located anteromedial to the left kidney, separated from the left adrenal gland and adherent to the 4th duodenal segment. During admission, her vital signs showed slight elevation of blood pressure (140\90–160\110) mmHg, thus 24-h urine metanephrine and normetanephrine were requested and the results revealed normal values. Upper gastrointestinal endoscopy failed to pass beyond the 3th duodenal segment and showed no pathologic evidence. According to her findings, a diagnosis of duodenal gastrointestinal stromal tumor (GIST) was suspected. During laparotomy, crises of hypertension and tachycardia followed by severe hypotension made the resection of the misdiagnosed mass very tricky. Immunohistochemical staining studies confirmed the diagnosis of paraganglioma. CONCLUSION: Paraganglioma is a life threatening disease and should always be considered as a differential diagnosis of asymptomatic retroperitoneal mass. The aim of our study is to present a challenging case of an undiagnosed retroperitoneal paraganglioma and to alarm our colleagues from such troubles.