Introduction:
Pheochromocytomas are rare catecholamine-secreting adrenal tumors, that can cause life-threatening complications and metastasize. Patients with hereditary pheochromocytoma have a significant risk of developing bilateral disease. Standard of care is radical adrenalectomy, which induces adrenocortical insufficiency when performed bilaterally. Adrenocortical function might be spared with partial adrenalectomy, however, at the risk of higher recurrence rates. This study compares outcomes of partial versus radical adrenalectomy in hereditary pheochromocytoma.

Methods:
Retrospective data from hereditary pheochromocytoma patients across 12 European centers  were analyzed with a median follow-up of 100 months. Contra- and ipsilateral recurrence, adrenocortical insufficiency, metastasis, and pheochromocytoma-specific mortality were analyzed, and compared in subgroups by initial presentation (unilateral or bilateral disease) and type of surgery.

Results:
From 256 patients, 75% initially presented with unilateral tumors and 25% with synchronous bilateral tumors. Radical adrenalectomy (n=223) and partial adrenalectomy (n=33) were performed.

In 191 patients with initial unilateral disease, 26% developed a metachronous contralateral tumor, with VHL, RET, and MAX mutations predisposing for contralateral disease. Ipsilateral recurrence was 0% with partial adrenalectomy, 3% with radical adrenalectomy.

In metachronous bilateral cases, risk of adrenal insufficiency was 75% when the first operation was a partial adrenalectomy compared to 14% if the second was performed partially (P = 0.17).

Overall, adrenocortical insufficiency risk was 46% after partial bilateral adrenalectomy vs. 100% after radical bilateral adrenalectomy. Recurrence was 9% with radical adrenalectomy vs. 18% with partial adrenalectomy (P = 0.73).

Conclusion:
In hereditary pheochromocytoma, partial adrenalectomy yields lower adrenocortical insufficiency rates than radical adrenalectomy. Recurrence after partial adrenalectomy was slightly but not significantly higher.