Metastatic Paraganglioma—Role for External Beam Radiation Therapy

There is no cure for metastatic paraganglioma or pheochromocytoma (PPGL). All treatment options are associated with risks and morbidity—many times the side effects of treatment exceed tumor-related morbidity. The first step in the management of metastatic PPGL is to assess the rate of tumor progression and, once determined, provide a proportionate treatment. Herein we demonstrate the role for external beam radiation therapy (EBRT).

Case Report

The patient was a 65-year-old man who had a 4 × 5 × 6–cm periaortic abdominal paraganglioma (PGL) resected elsewhere 12 years previously in 1990. It was found rather incidentally at the time of colonoscopy when the gastroenterologist noted a pulsating mass projecting into the colon. At the time, the patient was asymptomatic except for mild hypertension. After tumor resection (no details of the operative report were available) he was followed with computed tomography (CT) scan once a year for 3 years and annual biochemical testing. His most recent plasma normetanephrine was abnormal and led to the current consultation in 2002. The patient was asymptomatic. On physical examination the body mass index was 28.1 kg/m ² , blood pressure 130/80 mmHg, and heart rate 78 beats per minute. He appeared well.

INVESTIGATIONS

The laboratory tests were consistent with a recurrent catecholamine-secreting tumor ( Table 53.1 ). Abdominal CT scan and I-123 metaiodobenzylguanidine (MIBG) scintigraphy detected four sites of recurrent PGL in the upper abdomen with the largest lesion measuring 2.4 × 2.9 cm ( Fig. 53.1 ).

Table 53.1

Laboratory Tests.

Biochemical Test	Result	Reference Range
Sodium, mmol/L	143	135–145
Potassium, mmol/L	4.2	3.6–5.2
Creatinine, mg/dL	1.0	0.8–1.3
Plasma metanephrine, nmol/L	<0.2	<0.5
Plasma normetanephrine, nmol/L	1.85	<0.9
24-Hour urine:
Metanephrine, mcg	139	<400
Normetanephrine, mcg	1434	<900
Norepinephrine, mcg	189	<80
Epinephrine, mcg	5.3	<20
Dopamine, mcg	235	<400