Because of extensive intraoperative catecholamine release, extreme vascularization, and demanding localization, laparoscopic and retroperitoneoscopic excision of pheochromocytomas and retroperitoneal paragangliomas is challenging. In a prospective clinical study, 61 chromaffin neoplasms (52 pheochromocytomas, 9 paragangliomas) were removed endoscopically from 52 patients (30 males, 22 females; age 44.4 +/- 16.3 years) at 55 operations. Six patients showed multiple (two to five) tumors. Tumor size ranged from 1 to 7 cm (mean 3.6 +/- 1.4 cm). Twelve patients suffered from hereditary diseases. Seven patients had bilateral adrenal diseases; in three patients pheochromocytomas were removed on both sides synchronously. Four neoplasias were local recurrences (three pheochromocytomas, one paraganglioma). The laparoscopic route was chosen for six operations, and the retroperitoneoscopic technique was performed in 49 procedures. Partial adrenalectomy was performed in 19 operations (in all patients with bilateral diseases). High-dosage a-blockage with phenoxybenzamine was routinely used. There were no conversions to open surgery. Perioperative complications were minor (23%), and mortality was zero. The operating time for unilateral pheochromocytomas was 116 +/- 52 minutes (range 35-285 minutes) and depended on tumor size (<3 cm vs. > or = 3 cm; p <0.01), gender (p <0.01), and extent of resection (partial vs. complete; p <0.05). The operating time for bilateral pheochromocytomas ranged from 285 to 385 minutes, and it was 75 to 600 minutes for paragangliomas. Blood loss was 100 +/- 171 ml. Consumption of analgesics was low (mean 7 mg piritramide postoperatively). The median duration of postoperative hospitalization was 4 days. In six of seven patients with bilateral disease complete preservation of cortical function was achieved. Locoregional metastatic recurrence was found in one patient 3 years after retroperitoneoscopic adrenalectomy. Endoscopic removal of solitary, bilateral, multiple, and recurrent pheochromocytomas and retroperitoneal paragangliomas is feasible and safe but requires extensive experience in minimally invasive and endocrine surgery.