Primary aldosteronism due to bilateral micronodular hyperplasia and concomitant subclinical Cushing's syndrome: A case report.

Background Adrenal incidentaloma (AI) has been frequently encountered in the clinical setting. It has been shown that primary aldosteronism (PA) or subclinical Cushing's syndrome (SCS) are the representative causative diseases of AI. However, the coexistence of PA and SCS has been reportedly observed. Recently, we encountered a case of AI, in which PA and SCS coexisted, confirmed by histopathological examinations after a laparoscopic adrenalectomy. We believe that there were some clinical implications in the diagnosis of the present case. Case summary A 58-year-old man presented with lower right abdominal pain with a blood pressure of 170/100 mmHg. A subsequent computed tomography scan revealed right ureterolithiasis, which was the cause of right abdominal pain, and right AI measuring 22 mm × 25 mm. After the disappearance of right abdominal pain, subsequent endocrinological examinations were performed. Aldosterone-related evaluations, including adrenal venous sampling, revealed the presence of bilateral PA. In addition, several cortisol-related evaluations showed the presence of SCS on the right adrenal adenoma. A laparoscopic right adrenalectomy was then performed. The histopathological examination of the resected right adrenal revealed the presence of a cortisol-producing adenoma, while CYP11B2 immunoreactivity was absent in this adenoma. However, in the adjacent non-neoplastic adrenal, multiple CYP11B2-positive adrenocortical micronodules were detected, showing the presence of aldosterone-producing adrenocortical micronodules. Conclusion Careful clinical and pathological examination should be performed when a patient harboring AI presents with concomitant SCS and PA.