Adrenocortical Carcinoma with Suspected Dual Cortisol and Aldosterone Secretion: A Case Report

Adrenocortical carcinoma (ACC) is a rare malignancy, accounting for 0.05-2% of all malignant tumors. Most cases are sporadic and asymptomatic, often discovered incidentally via imaging. However, 50-60% present with autonomous hormonal secretion, with 45% producing excess cortisol, and only 1% exhibiting mineralocorticoid excess. We report a 43-year-old Filipino female with a 6-month history of abdominal bloating, proximal muscle weakness, edema, and hypertension. Laboratory tests showed hypokalemia (serum potassium 2.5-3.05 mmol/L; normal 3.3-5.0 mmol/L). Imaging revealed a neoplastic right suprarenal mass (adrenal origin vs confluent lymphadenopathy) described as an incidental, lipid-poor right adrenal mass measuring 4.7 x 3.6 x 6.1 cm, with contrast-enhanced Hounsfield units of 40, along with periportal and paraaortic lymphadenopathies. Biochemical evaluation indicated an intermediate probability of primary aldosteronism: suppressed plasma renin at 0.97 ug/L/hr (0.97 ng/mL/hr), normal plasma aldosterone 599.46 pmol/L (21.61 ng/dl), and aldosterone-renin ratio of 618 (pmol/L)/(ng/L/hr) (22.27 ng/dl/ng/mL/hr). Ideally, confirmatory testing with an aldosterone suppression test prior to imaging and adrenal vein sampling (AVS) should be performed to lateralize the lesion before surgery; however, the patient opted to proceed with surgery. The patient also had overt hypercortisolism, with non-suppressed serum cortisol of 31.88 µg/dL (reference <1.8 µg/dL) on a low-dose dexamethasone suppression test, suppressed ACTH at 2.81 pg/mL (reference 7.7-63.6 pg/mL) (Table 1), and clinical features of Cushing syndrome, including facial plethora, and proximal muscle weakness. While these findings support the diagnosis of an ACTH-independent hypercortisolism, current guidelines recommend confirmatory testing, including 24-hour urinary free cortisol or late-night salivary cortisol, before definitive evaluation to distinguish ACTH-dependent from ACTH-independent disease. Concomitant catecholamine and androgen excess were excluded with normal 24-hour urine metanephrines and serum DHEAS. Surgical removal via open adrenalectomy was performed. Histopathology confirmed ACC, supported by immunohistochemistry. Postoperative treatment included radiotherapy and planned adjuvant mitotane therapy. During follow-up, the patient's blood glucose and blood pressure worsened, requiring medication adjustments. Unfortunately, the patient succumbed to the disease seven months post-surgery. This case highlights the difficulties in assessing adrenal tumors that concurrently secrete cortisol and aldosterone, especially when biochemical results are inconclusive, emphasizing the need for careful assessment and prompt intervention in this rare coexistence.