Pheochromocytoma: role of preoperative diagnosis in the assessment of malignancy risk and in the choice of surgical approach

Pheochromocytomas are malignant in 5-26% of the cases. Differential diagnosis with benign lesions can be difficult even on a pathological basis. Local invasion and distant metastasis are the only well established indicators of malignancy. It has been reported that the risk of malignancy increases with the lesion size. Despite safe laparoscopic adrenalectomy (LA) has been reported for lesions up to 10 cm, it is considered hazardous for pheochromocytoma larger than 6 cm, because of the risk of malignancy and iatrogenic pheochromocytomatosis. We evaluated the possibility to pre-operatively recognize pheochromocytomas at risk of being malignant that should not be selected for LA. The medical records of all the patients who underwent adrenalectomy for pheochromocytoma were reviewed. All the preoperatively available data (demographic, clinical, biochemical and radiological) were recorded as well as final pathological diagnosis. Comparative analysis of patients with benign and malignant pheochromocytomas was performed. Sixty-three adrenalectomies for pheochromocytoma were performed in 60 patients. Fifty-seven benign and 6 malignant pheochromocytomas were identified. No significant difference was found between patients with malignant and benign lesions concerning age, gender, family history, symptoms, laboratory and radiological findings. In particular, no significant difference was found for lesion size between the benign (63.3 +/- 30.6 mm, range, 20-150) and the malignant group (48.6 +/- 16.5 mm; range, 30-70). The largest diameter recorded for a malignant lesion was 70 mm. No preoperatively available data can reliably differentiate between benign and malignant pheochromocytomas. All malignant lesions in this series were smaller than 7 cm. Thus, pheochromocytoma size does not seem a reliable predictor of malignancy. In absence of the evidence of gross local invasion or metastatic disease, LA can be safely proposed also for large lesions. Conversion is mandatory in presence of local invasion or difficult dissection that could involve inadequate resection.