A 35-year-old woman presenting with
abdominal pain was found to have mildly elevated
catecholamine levels and a retroperitoneal mass. The patient underwent a negative I-123
MIBG scintigraphy scan and a nondiagnostic fine needle aspiration. Eleven years later the patient presented with a
hypertensive emergency and markedly elevated
catecholamine levels. A subsequent I-123
MIBG scintigraphy scan showed intense uptake corresponding to the previously seen retroperitoneal mass. The patient underwent surgical resection and pathology confirmed the presence of a
paraganglioma. A
paraganglioma is an
extra-adrenal pheochromocytoma that contains chromaffin cells and is thus capable of producing
catecholamines. I-123 metaiodobenzylguanidine (
MIBG) scintigraphy has become the imaging study of choice for
paragangliomas and has a sensitivity of ∼77% to 100% in detecting functional
paragangliomas. This case demonstrates scintigraphic correlation of the functional transformation of a nonfunctional
paraganglioma in a time span of ∼10 years. Although there are previously published case reports of scintigraphic positive, nonfunctional
paragangliomas and scintigraphic negative chromaffin cell
tumors, there has been no prior documented case of scintigraphic transformation on
MIBG.