<s>[INST] context: The incidental adrenal mass is seen in as many as 1.3% of abdominal CT scans performed for other reasons. Adrenocoical adenomas are most common, followed by adrenocoical carcinoma, metastases from other primary cancers, and pheochromocytoma. Biochemical evaluation must weigh the prevalence of adrenal neoplasms against the consequences of a missed life-threatening diagnosis, as in pheochromocytoma. All adrenal masses should be evaluated for pheochromocytoma with measurement of 24-hour urine catecholamines and their metabolites. Aldosterone and coisol measurement are indicated if clinical features suggest aldosteronism or Cushing's syndrome. Fine-needle aspiration of adrenal masses is indicated for clearly cystic lesions or if metastasis is suspected based on the presence of another known primary. Fine-needle aspiration is not routinely indicated in the evaluation of adrenal lesions and is contraindicated until pheochromocytoma is definitively excluded. Adrenal lesions should be resected if they are functional, are larger than 6 cm., or have enlarged during follow-up. [/INST] question: Incidental adrenal masses: | options: A: May be seen in as many as 10% of abdominal CT studies B: Most commonly represent pheochromocytoma; adrenocoical adenoma, adrenocoical carcinoma, and metastases from other primary cancers occur less frequently C: May represent adrenocoical carcinoma if greater than 6 cm. in diameter D: Should be routinely evaluated by measurement of 24-hour urine levels of catecholamines and their metabolites, coisol, and aldosterone plus fine-needle aspiration | answer: C </s>