P-010 Incidental Discovery of a Malignant Adrenal Mass Presenting With Abdominal Pain and Cushing’s Syndrome: A Case Report

Abstract Introduction A middle-aged adult presented with vague abdominal pain and newly diagnosed hypertension. No significant past medical or surgical history was reported. Clinical Case The patient had a 2-month history of non-localized abdominal pain. Examination showed central obesity, facial rounding, skin thinning, easy bruising, and mild proximal muscle weakness. Abdominal imaging revealed a 5.8 cm left adrenal mass. Signs of Cushing’s syndrome prompted hormonal evaluation. Diagnostic Assessment Serum cortisol: 1750 nmol/L (↑) ACTH: 1.5 pg/mL (↓) Aldosterone: 163 ng/dL (↑) DHEA-S: 480 µg/dL (mild ↑) LDDST: No suppression → ACTH-independent Cushing’s Metanephrines: Normal → pheochromocytoma excluded Electrolytes: Mild hypokalemia CT scan: Heterogeneous adrenal mass, no clear signs of malignancy Post-op PET-CT: No residual/metastatic disease Open left adrenalectomy with en bloc splenectomy was performed. Histopathology confirmed adrenocortical carcinoma (ACC) based on Weiss criteria (high mitotic rate, nuclear grade, necrosis, capsular invasion). Post-op care: Hydrocortisone (20/10 mg/day) tapered Fludrocortisone 0.1 mg/day DHEA 25 mg/day Electrolytes and BP normalized within one week. Three months post-op, the patient showed clinical and biochemical improvement: cortisol 450 nmol/L, ACTH 18 pg/mL, aldosterone 12 ng/dL. Imaging showed no recurrence. Antihypertensives were discontinued. ACC is rare and often discovered incidentally. In this case, signs of Cushing’s syndrome with suppressed ACTH and failed dexamethasone suppression indicated autonomous cortisol production. Imaging lacked definitive malignant features, but histology confirmed ACC. Surgical resection is the mainstay of treatment; adjuvant therapy may be considered in high-risk cases. Conclusion This case highlights the importance of investigating adrenal incidentalomas thoroughly. Early diagnosis and surgery, combined with hormone replacement and follow-up, are essential for managing ACC and preventing recurrence.