True about adrenal pheochromocytoma is
Chromaffin negative
Mostly malignant
Bilateral in 10 percnt cases
Unilateral in 10 percnt cases
Refernce Robbins page no 1134 The "10 percent rule" forpheochromocytoma/paraganglioma--10% familial, 10% malignant, 10% extra-adrenal--is therefore no longer tenable. Current roles of pathology are limited to diagnosing primary or metastatic tumors and identifying features suggestive of malignant potential or hereditary disease.
Endocrinology