Routine preoperative (123)I-MIBG scintigraphy for patients with phaeochromocytoma is not necessary

Functional imaging using (123)I-meta-iodo-benzyl-guanetidine (MIBG) scintigraphy has alleged 100% specificity for phaeochromocytoma (PHAEO). Its benefit in patients with biochemical diagnosis of PHAEO is arguable when cross-sectional radiology can demonstrate the side-size of the adrenal tumours.

This is a retrospective review of clinical notes of patients undergoing adrenalectomy for PHAEO in a University centre.

Between January 2000 and December 2007, adrenalectomy for PHAEO was performed on 66 patients (28 M and 38 F, aged 24-82 years). Diagnosis was demonstrated by raised 24-h urine catecholamines (n = 14) or metanephrines (n = 52). The side and size of adrenal tumours were demonstrated on computed tomography (n = 58) and/or magnetic resonance imaging (n = 20) scans. MIBG scans were performed in 38 patients. Four of these patients were found to have non-adrenal pathology (haemangioblastomas, haemangioma, a bronchogenic cyst and an angiomyolipoma); hence, the positive predictive value of MIBG scan was 90%. In a further five patients, MIBG raised the suspicion of local metastatic disease but this was not confirmed on operative findings and no recurrence was detected in these patients during 6-92-month follow-up. This led to an overall rate of false-positive rate of 23%.

MIBG scintigraphy adds little to the routine preoperative management of patients with suspected PHAEO. Its use should be limited to the small minority of patients with negative cross-sectional imaging and those with recurrent or metastatic disease.