Application of CYP11B2 immunohistochemistry in the histopathological diagnosis of primary aldosteronism

Objective To evaluate the value of CYP11B2 immunohistochemistry in the histopathological diagnosis of primary aldosteronism(PA) among Chinese population. Methods Ninety-six cases of unilateral PA patients were retrospectively enrolled, and with 15 cases of non-hyperfunctioning adenoma, and 15 cases of cortisol producing adenoma as control. CYP11B2 immunohistochemistry was performed in the tumor sections of these patients and was analysed by semi-quantified method. The positive rate of CYP11B2 in tumor specimen of all cases enrolled was calculated and PA patients were subtypely classified based on their histopathological features and CYP11B2 expressions. Results The immune-positive rate of CYP11B2 in the PA group was 91.7% (88/96), with the control group being 6.7% (2/30, P<0.001). Subgroup analysis revealed that the immune-positive rate of CYP11B2 in the aldosterone producing adenoma group and unilateral hyperplasia group were 91.8% (78/85) and 90.9% (10/11), respectively. Based upon histopathological feature and CYP11B2 immunohistochemistry, PA patients were further subtypely classified as aldosterone producing adenoma (85/96), unilateral diffuse adrenocortical hyperplasia (7/96), unilateral mono-adrenocortical micronodules (1/96), unilateral multiple adrenocortical micronodules (1/96), and unilateral multiple aldosterone-producing cell clusters (multiple APCCs, 2/96). Conclusion CYP11B2 immunohistochemistry may serve as an useful tool for the histopathological diagnosis of PA. Key words: Primary aldosteronism; Immunohistochemistry; Pathological diagnosis