Evaluation of Cyp11b2 (Aldosterone syntase) activity in patients operated due to primary hyperaldosteronism by immunohistochemistry

Objective: Primary Aldosteronism is one of the most common causes of preventable hypertension. The prevalence of the disease is increasing with the increase in diagnostic and screening tests. The aim of the study is nomenclature histopatalogic findings and evaluate their relationship with clinical findings by demonstrating the aldosterone synthase enzyme activity, which is responsible for aldosterone production in the adrenal cortex, by immunohistochemical method. Materials and Methods: Nineteen cases who were followed up with the diagnosis of Primary Hyperaldosteronism at the Endocrinology Clinic of Çukurova University Faculty of Medicine Hospital and underwent adrenalectomy surgery between 2009 and 2022, Nineteen cases who were followed up and operated due to adrenal Cushing's syndrome, and two operated cases with nonfunctional adrenal adenoma were included. The patients were evaluated with semiquantitative H- score evaluation after pathological prognostic immunohistochemical staining. They were also grouped according to the HISTADO classification. Results: Aldosterone (ng/dl) and aldosterone renin ratios measured before the operation were found to be statistically significantly higher in the primary aldosteronism group than in the Cushing group. (P value: 0.019; 0.002, respectively) Negative correlation findings were found between the IHC score and the largest diameter of the tumor before surgery, and the findings were statistically significant. (r=-0.536 p=0.001). A total of 21 patients were grouped as APA (n = 10) and non-APA (n = 11) with their new pathological diagnosis. In the non-APA group, there was one patient diagnosed with APMM, one patient diagnosed with APN, one patient diagnosed with MAPN, 2 patients diagnosed with APACC and 6 patients diagnosed with MAPM. The mean IHC score of the patients was 136.6±78.86 in the APA group and 86.81±85.30 in the non-APA group. Conclusion: This study shows that determination of Cyp11b2 enzyme expression by immunohistochemistry is a powerful tool in identifying lesions responsible for hyperaldosteronism and subtype diagnosis. Keywords: Aldosterone synthase, Primary aldosteronism, Histaldo, Cyp11b2