Endocrine Abstracts

Introduction: Predicting clinical cure post-adrenalectomy for primary aldosteronism (PA) remains challenging despite established tools like the Aldosteronoma Resolution Score (ARS). While ARS offers clinical simplicity, its accuracy is moderate. CYP11B2 (HISTALDO) staining identifies aldosterone-producing cells, with classical staining associated with better outcomes, but overlooks factors like vascular remodelling, which ARS can capture. To address this, we developed the HISTAR score by integrating HISTALDO with ARS to improve postoperative prognostication.

Methods: Thirty consecutive PA cases (2016–2025) post-unilateral adrenalectomy were reviewed. Clinical cure was defined according to PASO criteria (blood pressure <140/90mmHg without medication for ≥6 months). ARS (score:0–5, cutoff ≥4) includes BMI, sex, hypertension duration, and antihypertensive count. HISTAR added 1 point for classical HISTALDO, maintaining the cutoff ≥4 to improve sensitivity. In 15 patients with HISTALDO data, multivariable logistic regression and ROC analysis compared ARS and HISTAR models.

Results: Clinical cure rate was 33%. Classical HISTALDO showed higher cure rates than non-classical (67% vs 25%), but statistically non-significant (p=0.24). In HISTALDO-typed cases, higher ARS (p=0.001) and HISTAR (p=0.002) scores were significantly associated with cure. ARS achieved AUC 0.90 (95% CI: 0.76–1.00, p<0.001). At ARS ≥4, sensitivity was 80%, specificity 80%, NPV 89%, PPV 67%, and accuracy 80%, comparable to published data. HISTAR achieved AUC 0.91 (95% CI: 0.77–1.00, p<0.001). At HISTAR ≥4, sensitivity and NPV were 100%, specificity 80%, PPV 71%, and accuracy 87%, supporting its clinical applicability.

Conclusion: To our knowledge, this is the first clinical–immunohistochemical score for predicting clinical cure in PA. HISTAR demonstrated improved sensitivity and NPV, without specificity loss, a novel finding unmatched by previous scores. Although based on a small cohort, these proof-of-concept data suggest integrating HISTALDO with ARS may improve prognostic accuracy and guide early postoperative mineralocorticoid antagonist use and personalised follow-up in PA. However, further validation is needed.