This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Disorders of Adrenal Gland, Subject name: Medicine
The most common cause of malignant adrenal mass is: 
Select and explain. 
A. Adrenocoical carcinoma, B. Malignant Phaeochromocytoma, C. Lymphoma, D. Metastasis from another solid tissue tumor
A: Adrenocoical carcinoma
Answer: A: Adrenocoical carcinoma 
Explanation: Malignant Adrenocoical carcinoma 2-5 Malignant pheochromocytoma <1 Adrenal neuroblastoma <0.1 Lymphomas (including primary adrenal lymphoma) <1 Metastases (most frequent: breast, lung) 1-2