Histologically benign but telomerase positive adrenal pheochromocytoma

Adrenalectomy was performed on a 37-year-old woman with right adrenal pheochromocytoma. Although the histological diagnosis was benign, telomerase repeat amplification protocol (TRAP) demonstrated positive telomerase activity. Thirty-five months after adrenalectomy, a recurrent tumor was found. Forty-seven months after adrenalectomy, bone metastases also appeared. Malignant pheochromocytoma was clinically diagnosed. Our experience suggests that telomerase-positive tumor cells are highly likely to repeat cell proliferation when they are left in the patient's body, and lead to recurrence. Therefore, telomerase-positive tumors should be clinically treated as malignant even if they have been histologically diagnosed as benign.