Analysis Of Clinical Features Of Potential Malignant Pheochromocytoma And Related Research Of SDHB And SDHD

Purpose: To evaluate the expression of succinate dehydrogenase(SDH)B and SDHD in benign,potentially malignant and malignant pheochromocytoma(PCC)and paraganglioma(PGL,collectively abbreviated as PPGLs),explore the relationship between the expression of SDHB and SDHD and the clinical and pathological characteristics of the tumor,and provide a pathological diagnosis basis for the early identification of benign and malignant PPGLs(especially potential malignancy).Methods:1.The present study included 387 patients with PPGLs,who were treated between January 2000 and December 2018 at the Affiliated Hospital of Qingdao University in China,including 321 PCCs and 66 PGLs.2.According to the diagnostic principles in the 2016 expert consensus on the diagnosis and treatment of PPGLs and PASS scores,it was divided into three groups: benign,potentially malignant,and malignant.Analyze and compare the clinical data,laboratory tests and pathological parameters among the three groups.3.SDHB and SDHD immunohistochemical staining were performed on 53 PPGLs(25benign,15 potentially malignant,and 13 malignant).The relationship between tumor immunohistochemical staining results,clinical manifestations and pathological results was analyzed.Results:1.Clinicopathological data Compared with the clinical data of the three groups of benign,potential malignant and malignant PPGLs,it was found that the age of onset of the malignant group was younger than that of the benign group(p<0.05),the average age of onset was 47.11 ± 13.89 years,and most of them were located extra-adrenal(p<0.01),tumor diameter was 99.30 ±56.23 mm,and the median Ki67 was 5.00%,which were higher than those in benign group(p<0.01).Compared with the benign group,the tumors in the potentially malignant group were also located outside the adrenal glands(p<0.01).The diameter of the tumors was 66.14± 19.78 mm and the median Ki67 was 4.00%,which were also higher than those in the benign group(p<0.05),and there was no statistically significant difference in gender,blood pressure,body mass index(BMI),fasting blood glucose(FBG),fasting insulin(FINS),blood lipid,serum potassium,uric acid and other clinical indicators among the three groups.Plasma renin activity(PRA),aldosterone(ALD),cortisol,24-hour urine free catecholamine(CA)and other hormone secretion levels were not significantly different.According to the ROC curve,the best cut-off value of tumor diameter for diagnosing potentially malignant PPGLs is 59.5mm.When the diameter is greater than 59.5mm,the sensitivity of diagnosing potentially malignant PPGLs is 76.9%,and the specificity is 78.5%.2.Immunohistochemical staining results2.1 In this study,SDHB immunohistochemical staining results showed that the positive rates of SDHB staining in benign,potentially malignant,and malignant groups were 80%,40%,and 38%,respectively.The potential malignant group and malignant group had a lower positive rate of SDHB staining than the benign group and the difference was statistically significant(P <0.05).And the proportion of SDHB staining(++)in potential malignant and malignant group was significantly lower than that in benign group(P <0.05).2.2 In this study,SDHD immunohistochemical staining results showed that the positive rates of SDHD staining in benign,potentially malignant,and malignant groups were 32%,67%,and 69%,respectively.The potential malignant group and malignant group had a higher positive rate of SDHD staining than the benign group and the difference was statistically significant(P <0.05).3.Correlation analysis The positive expression of SDHB was negatively correlated with the location of the tumor outside the adrenal gland(r =-0.377,p = 0.044),and the positive expression of SDHD was positively correlated with the location of the tumor outside the adrenal gland(r = 0.501,p = 0.006).The expressions of SDHB and SDHD had no significant correlation with age,tumor diameter,Ki67,hormone levels and other indicators.Conclusion:Our study found that Ki67 and tumors diameters were larger in the potential malignant PPGLs,and the tumors were mostly located outside the adrenal gland.The negative rate of SDHB staining and the positive rate of SDHD staining were higher,which were consistent with the results of malignant PPGLs.This suggests that we can combine clinical,pathological,immunohistochemical and other indicators to identify early malignant tumors,and have certain guiding significance for the early diagnosis and treatment of patients with malignant PPGLs.