Endocrine Abstracts

Introduction: Pheochromocytomas are rarely malignant, defined by the presence of cathecholamine – producing metastases. Malignant pheochromocytoma responds poorly to chemotherapy and radiotherapy. ¹³¹I-MIBG therapy can be used to prolong survival, with minor side effects.

Case: A 45-years old woman known with malignant pheochromocytoma, with a long medical history, first came to our clinic in July 2012. Her diagnosis was suspected in 1999 when she experienced hypertensive crises associated with headache, palpitations and diaphoresis; investigations revealed high levels of urinary meta/normetanephrines and a 11 cm right adrenal tumor. She underwent right adrenalectomy and nephrectomy (2001). Pathology report confirmed pheochromocytoma with lymph nodes metastases. After surgery she had normal BP. In 2005 an imaging check-up revealed a liver metastasis which was surgically removed and bilateral pulmonary metastases. Thereafter, she was oligosymptomatic, with occasional palpitations, in spite of her high levels of plasmatic and urinary meta/normetanephrines. In 2012, CT and ¹²³I-MIBG scans confirmed pulmonary and mediastinal metastases, without local recurrence. We initiated treatment with a combined α/β blocker. She was then admitted for radionuclide treatment, receiving 150 mCi ¹³¹I-MIBG. The concentrations of plasma and urinary meta/normetanephrines were measured after 3/6/9 months. During the follow-up we discovered an initial increase (at 3 months) in the hormonal values, possibly due to the release of catecholamines from the irradiated tumor tissues. At 9 months since ¹³¹I-MIBG, the hormonal values were comparable with those before radionuclide therapy, with little decrease in lung metastases size. Despite this she remained oligosymptomatic. No side effects were observed.

Conclusion: Malignant pheochromocytoma with pulmonary metastases can be oligosymptomatic despite a long medical history, high levels of meta/normetanephrins and a poor early response to ¹³¹I-MIBG treatment.