Which of the following is most reliable feature of malignant transformation of pheochromocytoma ?: (A) Presence of mitotic figures, (B) Capsular invasion, (C) Vascular invasion, (D) None
Answer is D. Ans. is None "Because benign and malignant pheochromocytomas may have an identical histological appearance, the only absolute criterion of malignancy is metastasis." "The diagnosis of malignant pheochromocytoma is made only when metastasis is demonstrated."