10% Tumour is: (A) Pheochromocytoma, (B) Papillary Thyroid Carcinoma, (C) Follicular Thyroid Carcinoma, (D) Brown’s Tumor
Answer is A. 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