Recurrence of a Pheochromocytoma With TNEM127 Mutation Negative on 18F-FDOPA and 18F-FDG but Positive on 123I-MIBG and 68Ga-DOTATOC Imaging.

We report the case of a 75-year-old woman with liver metastasis as a recurrence of a pheochromocytoma resected 10 years ago, with a rare germline mutation in transmembrane protein 127, falsely negative on 18F-FDOPA and 18F-FDG PET/CT scans but strongly positive on 123I-MIBG scintigraphy and on 68Ga-DOTATOC PET/CT. Functional imaging has a key role in diagnosis of pheochromocytoma and paraganglioma, especially 18F-FDOPA shows very high sensitivity and specificity. However, 18F-FDOPA might be falsely negative in some of these tumors, depending on specific mutations, and thus MIBG or 68Ga-DOTATOC imaging could be an alternative.