Giant cystic pheochromocytoma/paraganglioma: Misdiagnosis and analysis of clinical characteristics

Introduction : To explore the clinical characteristics of giant cystic pheochromocytoma and misdiagnosis, and provide experience for correct and timely diagnosis and treatment. Methods: A total of 170 cases of pheochromocytomas and paragangliomas (PPGL) diagnosed at the First Affiliated Hospital of Chongqing Medical University from April 2011 to April 2020 were confirmed by clinical, catecholamine metabolites, imaging, or surgical pathology. The patients were classified into two groups according to the maximum diameter of the tumor and the cystic components. The clinical characteristics of patients timely diagnosis and misdiagnosis in the giant cystic group are summarized. Furthermore, the differences in demographics, clinical manifestations, laboratory examinations, imaging features, treatment, and tumor characteristics between the two groups were analyzed. Results: Of the 17 patients in the giant cystic group, eight (47.1%) patients were misdiagnosed. Misdiagnosis and mistreatment characteristics of PPGL were as follows: females (accounted for 50%); median age was 51 years: more patients had normal blood pressure; greater mass effect at the onset; larger tumors; median time to diagnosis extension was 180 days; and the misdiagnosed disease was mainly: tumors of adjacent organs, digestive system, cardiovascular system, urinary system, nervous system, and endocrine system diseases. The giant cystic group had a greater mass effect than the non-cystic group (P < 0.05). The proportion of the triad of pheochromocytoma and hypertension were lower; however, this difference was not statistically significant. Blood MN(metanephrine) was higher, hemoglobin and blood low-density lipoprotein levels were lower (P < 0.05). The proportions of tumor calcification and hemorrhagic necrosis were significantly higher (P < 0.05). There was more intraoperative bleeding, more patients who underwent blood transfusions, and a longer postoperative hospital stay; however, the difference was not statistically significant. Conclusion: Giant cystic PPGL is not uncommon, clinical manifestations may not show as high blood pressure, and imaging is not easy to identify with the large space-occupying adjacent organs. Therefore, it is easily misdiagnosed when giant cystic lesions of unknown nature,and require early biochemical examination, combined with imaging features, clearing the nature of the tumor to improve the rate of correct diagnosis.