Laparoscopic resection of aortocaval paraganglioma diagnosed by serial increase in urinary metanephrines after bilateral adrenalectomy in a patient with multiple endocrine neoplasia type 2A

INTRODUCTION: Although bilateral pheochromocytoma is prevalent in patients with multiple endocrine neoplasia type 2, extra‐adrenal tumors rarely occur in the aortocaval area. CASE PRESENTATION: A 35‐year‐old man with multiple endocrine neoplasia type 2A (RET codon Cys634Arg mutation) underwent bilateral adrenalectomy for metachronous pheochromocytoma. After bilateral adrenalectomy, urinary metanephrines decreased below the measurement sensitivity. The levels of urinary metanephrines were serially elevating to a peak of 187 ng/mgCr during the 11‐year follow‐up period; however, urinary normetanephrine levels remained almost stable. (123)I‐metaiodobenzylguanidine single‐photon emission computed tomography revealed abnormal accumulation with a mass of 25 × 18 mm in diameter in the aortocaval space cranially to the renal vessels. The extra‐adrenal paraganglioma was successfully resected using transperitoneal laparoscopic surgery. CONCLUSION: The serial increase in urinary metanephrine levels was useful for the detection of the recurrent tumor in a patient who had undergone bilateral adrenalectomy.