Functional imaging with 11C-metomidate PET for subtype diagnosis in primary aldosteronism

Objective Endocrine Society guidelines recommend adrenal venous sampling (AVS) in primary aldosteronism (PA) if adrenalectomy is considered. We tested whether functional imaging of adrenal cortex with 11C-metomidate (11C-MTO) could offer a noninvasive alternative to AVS in the subtype classification of PA. Design We prospectively recruited 58 patients with confirmed PA who were eligible for adrenal surgery. Methods Subjects underwent AVS and 11C-MTO-PET without dexamethasone pretreatment in random order. The lateralization of 11C-MTO-PET and adrenal CT were compared with AVS in all subjects and in a prespecified adrenalectomy subgroup in which the diagnosis was confirmed with immunohistochemical staining for CYP11B2. Results In the whole study population, the concordance of AVS and 11C-MTO-PET was 51% and did not differ from that of AVS and adrenal CT (53%). The concordance of AVS and 11C-MTO-PET was 55% in unilateral and 44% in bilateral PA. In receiver operating characteristics analysis, the maximum standardized uptake value ratio of 1.16 in 11C-MTO-PET had an AUC of 0.507 (P = n.s.) to predict allocation to adrenalectomy or medical therapy with sensitivity of 55% and specificity of 44%. In the prespecified adrenalectomy subgroup, AVS and 11C-MTO-PET were concordant in 10 of 19 subjects with CYP11B2-positive adenoma and in 6 of 10 with CYP11B2-positivity without an adenoma. Conclusions The concordance of 11C-MTO-PET with AVS was clinically suboptimal, and did not outperform adrenal CT. In a subgroup with CYP11B2-positive adenoma, 11C-MTO-PET identified 53% of cases. 11C-MTO-PET appeared to be inferior to AVS for subtype classification of PA.

Diagnostic performance of adrenal CT in the differentiation of adenoma and pheochromocytoma

Background Differentiation of adenoma and pheochromocytoma on computed tomography (CT) may be problematic. Purpose To investigate if adenoma and pheochromocytoma can be differentiated with adrenal CT. Material and Methods A total of 147 pathologically proven adrenal masses (119 adenomas, 28 pheochromocytomas) that had undergone adrenal CT were retrospectively evaluated. Lesion attenuation on unenhanced phase (UEP), portal phase (PP), 15-min delayed phase (DP), absolute/relative percentage enhancement wash-out (APEW/RPEW), and qualitative features were recorded. Student’s t-test for parametric data, Mann–Whitney U test for non-parametric data, and Fisher’s exact test for categorical data were used. Diagnostic performance of CT attenuation was assessed by area under the curve (AUC) of the receiver operating characteristics. Results APEW of adenomas was not significantly different from pheochromocytomas; 68.4% and 59% ( P = 0.284). Adenomas had significantly higher RPEW; 57.3% vs. 37.4% ( P = 0.004). Of pheochromocytomas, 50% met APEW >60% or RPEW >40% criteria, and therefore were misclassified as adenoma on wash-out CT. Of those, 80% (4/5) were < 3 cm. UEP, PP, and DP attenuations of pheochromocytomas were significantly higher than adenomas; however, they were overlapping. AUC for UEP, PP, and DP was 0.906, 0.784, and 0.926, respectively. Larger pheochromocytomas were more likely to contain necrosis compared to smaller pheochromocytomas and adenomas; 41.6% vs. 12.5% vs. 3%. Homogeneous enhancement was seen in 25% of pheochromocytomas and 49% of adenomas ( P = 0.018). No significant difference was found in terms of lesion borders and presence of fat/calcification ( P > 0.05). Conclusions A considerable percentage of pheochromocytomas, especially smaller ones, demonstrate adenoma-like wash-out on CT. Heterogeneous enhancement, higher attenuation, and necrosis are more suggestive of pheochromocytoma.

Malignancy Risk and Hormonal Activity of Adrenal Incidentalomas in a Large Cohort of Patients from a Single Tertiary Reference Center

Background: A rise in adrenal incidentalomas (AIs) detection has been observed recently. Even though AIs are detected in asymptomatic patients, thorough assessment may reveal hormonal and metabolic abnormalities or malignant character. Methods: Medical records of 2005 patients (1301 women, 704 men) with 2498 tumors aged 61 ± 11.3 (18–93) years, who had been hospitalized due to AI diagnosis, were reviewed. Patients underwent clinical examination, adrenal CT and hormonal assessment. In patients subjected to adrenalectomy, histopathological character of AI was confirmed. Results: AIs most frequently occurred in patients in their 7th decade of life. Hypertension was present in 76.6%, glucose metabolism disorders in 41.3%, and hypercholesterolemia in 60.1% of patients. Lipid-rich adenomas (83.2%) and hormonally inactive tumors (83.1%) predominated. Autonomous cortisol secretion was present or suspected in 6.6%, pheochromocytoma in 4.7%, hyperandrogenism in 3.1%, and primary hyperaldosteronism in 2.4% of patients. The risk of malignancy increased in patients with tumors >6 cm was 37.7%. The logistic regression analysis revealed that the strongest predictor of hormonal activity of AIs was lipid-poor picture on CT scan (OR 7.072; CI 5.118–9.771), while the most important factor increasing the risk of malignancy was lipid-poor adenoma or non-adenoma on CT scan (OR 4.843; CI 1.697–13.819). Final histopathology was available for 214 tumors; 106 adrenocortical adenomas, 46 pheochromocytomas, and 18 adrenocortical carcinomas were diagnosed. Conclusion: Most AIs are hormonally inactive adenomas. The most frequent hormonal manifestation of AI is subclinical hypercortisolemia. Presence of AI is often accompanied by features of metabolic syndrome. The tumor density on CT scan picture may be predictive of both hormonal activity and the risk of malignancy. Tumors of all sizes may exhibit hormonal activity, while the risk of malignancy significantly increases with the size above 6 cm.

Insuficiencia mineralocorticoide posterior a adrenalectomía unilateral como tratamiento para hiperaldosteronismo primario: Reporte de un caso

Introducción: El hiperaldosteronismo primario es la causa más frecuente de hipertensión de origen endocrino. Presentamos una insuficiencia de mineralocorticoides como complicación posterior a adrenalectomía unilateral.Presentación del caso: Paciente femenina de 51 años, con historia de larga data de hipertensión resistente, hospitalizaciones por hipopotasemia y enfermedad renal crónica hipertensiva. Se confirmó hiperaldosteronismo primario con valores altos de aldosterona e indetectables de renina. La TAC de adrenales mostró un adenoma derecho de 23 mm. Dado el cuadro clínico severo y valores bioquímicos, se llevó directamente a adrenalectomía derecha. Posterior al procedimiento retiran todos los antihipertensivos; sin embargo, la paciente presenta hipotensión, deterioro de la función renal e hiperpotasiemia con valores de aldosterona y renina inapropiadamente normales. Se inició manejo con hidratación y fludrocortisona, presentando adecuada respuesta con normotensión, potasio y azoados normales.Discusión: La insuficiencia de mineralocorticoides es una complicación poco conocida, aunque frecuente posterior adrenalectomía por hiperaldosteronismo, cursa con hiperpotasiemia, hipotensión y deshidratación. Son factores de riesgo un hiperaldosteronismo severo, de larga data y falla renal. Requiere manejo con fludrocortisona, usualmente de manera transitoria durante semanas a meses.Conclusión: Se deben vigilar signos de hipoaldosteronismo posterior a la adrenalectomía por hiperaldosteronismo primario, dado que hasta un tercio de pacientes puede presentar insuficiencia de mineralocorticoides.Abstract Introduction: Primary hyperaldosteronism is the most frequent endocrine cause of hypertension. We present the case of a patient with mineralocorticoid insufficiency secondary to unilateral adrenalectomy. Case report: 51 year-old female with a long-standing history of resistant hypertension, multiple admissions due to hypokalemia and chronic kidney disease secondary to hypertension. High aldosterone levels and undetectable renin levels confirmed the diagnosis of primary hyperaldosteronism. Adrenal CT scan showed a 23-mm right adrenal adenoma. Given the severe presentation and confirmatory laboratory results, the patient underwent right adrenalectomy. After the surgical intervention, all antihypertensive medications were withdrawn, but later on, the patient presented hypotension, acute kidney injury and hyperkalemia with inappropriately normal aldosterone and renin levels. Intravenous fluids and fludrocortisone were started with adequate response given by normal blood pressure, normal potassium levels and normal kidney function. Discussion: Mineralocorticoid insufficiency is not a very well-known, although frequent, complication of adrenalectomy secondary to hyperaldosteronism. Patients present with hyperkalemia, hypotension and dehydration. Risk factors for developing mineralocorticoid insufficiency include severe hyperaldosteronism, long-standing hyperaldosteronism and kidney failure. Its management requires the transient use of fludrocortisone for weeks to months. Conclusion: Signs of aldosterone insufficiency must be followed after adrenalectomy secondary to primary hyperaldostornism, given that up to one third of patients may present with mineralocorticoid insufficiency.

Prevalence of primary aldosteronism among bulgarian hypertensive patients

Primary aldosteronism (PA) has long been considered a rare disease, but a higher prevalence was suggested recently. The aim of this study was to evaluate the prevalence of PA in a group of Bulgarian hypertensive patients, including patients with adrenal incidentalomas (AI). The aldosterone to renin ratio (ARR)>750 was used as a positive screening test and the Captopril test was performed to confirm the diagnosis. Adrenal CT scan was used to differentiate between the main subtypes of PA- aldosterone-producing adenoma (APA) and idiopathic hyperaldosteronism (IHA). The diagnosis of APA was retrospectively confirmed after surgery. After excluding other forms of endocrine hypertension, except PA, we investigated a total of 472 consecutive hypertensive patients, among them 96 patients with AI. Final diagnosis of PA was reached in 38 patients (8.05%) in the entire hypertensive population and in 12 patients (12.5%) among hypertensive patients with AI. In the group of PA, 15 patients (39.5%) were diagnosed with APA and 23 patients (60.5%) had an IHA. Among all patients with PA 21 (55.3 %) presented with hypokalemia. Our findings of a relatively high prevalence of PA support an early diagnosis of this potentially curable disease, especially in hypertensive patients with AI.