I-123 MIBG Scintigraphy and 68Ga-DOTANOC PET/CT Negative But F-18 DOPA PET/CT Positive Pheochromocytoma

Abstract

We observed a 34-year-old man who was incidentally found to have an adrenal mass during surgical follow-up for perforated ulcer. The patient was subjected to I-123 MIBG scintigraphy, 68Ga-DOTANOC PET/CT, and F-18 DOPA PET/CT. Only F-18 DOPA PET/CT showed evidence of an avid adrenal mass. A CT-guided biopsy was performed and it was suggestive for pheochromocytoma. He underwent surgery and a pheochromocytoma, about 40 mm in diameter, was detected. Traditionally, I-123 MIBG scintigraphy has been used in detecting chromaffin cell tumors, but more recently it had been demonstrated that a certain part of pheochromocytoma could be false-negative on scintigraphy.