Functional imaging as an aid to decision-making in metastatic paraganglioma

Malignant paraganglioma is a rare and slow growing tumour of neuroendocrine origin. At the time of diagnosis, the tumour is usually widespread, with l imited therapeutic options. A variety of functional imaging studies are ava ilable for staging the disease, guiding therapy and monitoring treatment re sponse. These include I-123-MIBG or I-131-MIBG In-111-pentetreotide or In-1 11-lanreotide (somatostatin analogues), and F-18-FDG positron emission tomo graphy. Various radionuclides, including I-131 and Y-90, can be targeted to the tumour using MIBG or pentetreotide. Such targeted radionuclide therapy may provide valuable long-term palliation in such patients. We present two cases with metastatic paragangliomas who had widespread soft tissue and bo ne metastases. One patient was treatment naive and the second had received previous chemotherapy. The functional imaging work-up performed and the tar geted radionuclide therapies considered in these patients are described. Bo th patients were treated with I-131-MIBG. Partial tumour response and compl ete symptomatic and hormonal response was achieved in one patient: in the s econd patient there was no change.