Endocrine Abstracts

We report two cases of MIBG avid secretory phaeochromocytoma in 2 middle-aged ladies. Adrenalectomy, after standard preparation, was performed successfully and histology confirmed complete excision of a phaeochromocytoma in both cases; however, there was capsular infiltration and metastasis to a neighboring lymph node in the first case. In this case, surveillance CT scans 3 and 6 months later showed left adrenal bed recurrence and rapidly growing lesions in the right lobe of the liver but normal urinary catecholamines. Right hepatic lobectomy was performed successfully and histology confirmed aggressive phaeochromocytoma. In view of the MIBG avidity, MIBG therapy was administered 7 weeks after surgery. End of therapy scan showed abnormal uptake in the left lobe of the liver, mid and lower abdomen, pelvis, right hip, neck and the spine. The patient subsequently received palliative radiotherapy for painful metastases in the ribs and 2 cycles of palliative chemotherapy before she died 10 months after the second surgery.

In the second case, repeated radiological surveillance revealed a 14 mm solitary lesion in the lower lobe of the right lung 2 years after surgery. This was MIBG positive. Complete excision of the lung lesion was achieved surgically and histology confirmed a metastatic phaeochromocytoma. Adjuvant MIBG therapy was given 2 months later and the end of therapy scan was negative. The patient remains disease free on clinical, biochemical and radiological grounds 4 years after initial surgery.

These cases highlight the importance of routine surveillance imaging after successful initial surgical treatment of phaeochromocytoma and the fact that negative biochemical markers do not exclude a recurrence or metastases of a previously secretory phaeochromocytoma. In addition, surgical management of a solitary metastasis can be very successful. However, the benefits of using adjuvant MIBG therapy after complete surgical excision of a suspicious MIBG-avid phaeochromocytoma or its metastases remain unproven.