Stable disease and improved health-related quality of life (HRQoL) following fractionated low dose131I-metaiodobenzylguanidine (MIBG) therapy in metastatic paediatric paraganglioma: observation on false “reverse” discordance during pre-therapy work up and its implication for patient selection for high dose targeted therapy

Metastatic Extra-Adrenal Pheochromocytoma with Single Kidney and Renal Compromise: A Case Report of Excellent Response, Tolerability, and Outcome to a Modified Regimen of 131I-mIBG, and Decision-Making between 131I-mIBG Therapy and PRRT

Determining the choice and the goal is key element for decision-making of a systemic radionuclide therapy. They should be clearly defined in deciding and individualizing the dose and regimen. For iodine-131 metaiodobenzylguanidine (131I-mIBG) therapy, the important considerations during dose fractionation include disease burden, tumor biology, functional symptoms, and associated comorbidities, all of which are important determinants for the intent and course of treatment. Herein, we present the case of a 67-year-old elderly female with highly functional metastatic recurrent extra-adrenal pheochromocytoma (presenting 42 years after the primary surgery and 32 years following excision of pararenal recurrence) with multiple comorbidities including single kidney and borderline renal compromise, treated successfully with a relatively lower dose of 131I-mIBG (cumulative dose of 22.2 GBq in four cycles with a mean dose of 5.7 GBq per therapy cycle). The excellent tumor burden reduction, hormonal tumor marker response, and most importantly asymptomatic status could be achieved with the administered dose. On follow-up, none of the pretherapeutic parameters (including renal function) showed any further derangement compared with the baseline during next 24 months following the treatment. All cycles were well tolerated with only reversible hematological toxicity that normalized without any active intervention. The report is intended to provide some guidance for future therapeutic regimens.

Malignant pheochromocytoma of the organ of Zuckerkandl requiring aortic and vena caval reconstruction

OBJECTIVE

To describe a case of a malignant pheochromocytoma located in the organ of Zuckerkandl that required aortic and vena caval resection and reconstruction.

METHODS

We present a case report that includes clinical, laboratory, and radiographic data as well as photographs, results from pathology, and a brief review of the literature.

RESULTS

A 46-year-old man was referred for evaluation of a 1.4-cm left adrenal mass incidentally discovered on an abdominopelvic computed tomography (CT) scan. Subsequent laboratory evaluation revealed the following values: urine norepinephrine, 252 microg/24 h; urine normetanephrine, 1122 microg/24 h; urine metanephrine, 162 microg/24 h; urine epinephrine, 7 microg/24 h; urine vanillylmandelic acid, 8 mg/24 h; and plasma metanephrine, 98 pg/ mL. Imaging characteristics of the left adrenal mass were consistent with a benign adenoma, but CT also demonstrated a hypervascular para-aortic mass. 123I-metaiodo-benzylguanidine scanning with fusion CT imaging demonstrated increased radiopharmaceutical uptake within the para-aortic mass consistent with a paraganglioma in the organ of Zuckerkandl. Findings from CT angiography of the abdomen and pelvis suggested aortic involvement and vena caval thrombus. The mass was excised en bloc, including portions of the aorta, inferior vena cava, and right ureter. The aorta and vena cava were reconstructed using Dacron grafts. The remaining right ureter and kidney were removed to avoid the possibility of a urine leak from an ureteroureterostomy. Final pathologic and operative findings confirmed a malignant pheochromocytoma of the organ of Zuckerkandl with invasion into the wall of the inferior vena cava and tumor thrombus extending into the lumen.

CONCLUSION

Malignant pheochromocytoma of the organ of Zuckerkandl involving the aorta and inferior vena cava is exceedingly rare, and although surgical resection and reconstruction can be radical and aggressive, this treatment offers the only chance for cure.

Whole-body iodine-131 metaiodobenzylguanidine imaging for detection of bone metastases in patients with paraganglioma: comparison with bone scintigraphy

Iodine-131 metaiodobenzylguanidine ((131)I-MIBG) therapy is an effective treatment for patients with malignant paraganglioma for which surgical resection is not indicated. We performed high-dose (131)I-MIBG therapy on two patients with malignant paraganglioma and multiple bone metastases. The bone metastases were diagnosed by magnetic resonance imaging (MRI). Metastatic bone lesions were evaluated by whole-body (131)I-MIBG imaging and bone scintigraphy. Whole-body (131)I-MIBG imaging showed extensive metastatic bone lesions, whereas conventional bone scintigraphy did not. There was a remarkable discrepancy between (131)I-MIBG imaging and bone scintigraphy in the diagnosis of metastatic bone lesions of malignant paraganglioma in our two patients. High-dose (131)I-MIBG imaging may detect early stages of bone metastases, compared with bone scintigraphy, in patients with malignant paraganglioma.