10% Tumour is
Pheochromocytomas normally obey the “rule of 10”. Hence, they are also called the “10% tumor”. i.e. 10% of pheochromocytomas are: 

Familial. 
Malignant. 
Bilateral. 
Extra-adrenal. 
Seen in children
Pheochromocytoma
Papillary Thyroid Carcinoma
Follicular Thyroid Carcinoma
Brown’s Tumor