Which of the following is most reliable feature of malignat transformation of pheochromocytoma?: (A) Presence of mitotic figures, (B) Capsular invasion, (C) Vascular invasion, (D) None
Answer is D. Determination of malignancy in pheochromocytoma is difficult. Benign pheochromocytomas show mitotic figures and vascular and capsular invasion. So none of the above said features will help to determine malignancy. Therefore,the definitive diagnosis of malignancy in pheochromocytoma is based exclusively on the presence of metastases. Ref: Robbins and cotrans 9e