Adrenocortical carcinoma is a rare endocrine malignancy with a bimodal age distribution pattern that affects women more than men. More than half of the patients present with hormone excess manifestations such as Cushing's syndrome and virilization. Non-functional tumors usually are diagnosed incidentally following imaging studies due to a mass effect or metastatic disease. Surgical resection is considered the best curative treatment for these tumors. Case Presentation. A 70-year-old woman presented with a 3-month history of diffuse intermittent abdominal discomfort, weight loss, and additional hair growth. Imaging investigations revealed a large 187 × 85 × 140 mm mass between the liver and upper pole of the right kidney which has displaced the adjacent structures. Hormonal evaluations detected high levels of cortisol and adrenal androgens. She underwent open adrenalectomy and right nephrectomy due to severe adhesion of the mass. Histopathological evaluations revealed adrenocortical carcinoma and the patient received adjuvant radiotherapy. Precise physical examination, hormonal evaluation, and imaging studies play a key role in differentiating malignant adrenal masses in all patients, especially in those with vague symptoms. Radical excision of the mass and appropriate adjuvant chemotherapy or radiotherapy improve the outcome for patients.