Diagnosis is pheochromocytoma.
You can not tell histologically whether a pheochromocytoma is benign or malignant. Demonstration of metastases is the only way to diagnose malignancy. If the same type of neoplasm arose outside of the adrenal gland it would be called a paraganglioma. Sudden release of catecholamines may precipitate congestive heart failure, pulmonary edema, myocardial infarction, ventricular fibrillation, cerebral hemorrhage or death. However, pheochromocytomas are rare tumors, and therefore most hypertension is not caused by pheochromocytomas.