Abstract: Objective To analyze the clinical features of patients with subclinical pheochromocytoma (PHEO). Methods Review of clinical features of 22 patients with subclinical PHEO treated in PUMC hospital from 1997 to 2007. Results All patients were asymptomatic. 24hrs urinary catecholamine excretion was detected normal in 10 of 22 cases, while increased in the others. 16 patients were prepared withα-receptor blocker before operation. During the operation, BPmax (maximal blood pressure) before tumor resection, BPmin (minimal blood pressure) after resection and ΔBP(BPmax－BPmin) were 163±34/86±20 mmHg，105±12/61 ±10 mmHg and 58±37/25±21 mmHg, Respectively, in the prepared group. And they were 169±36/104±20 mmHg, 97±18/56±13 mmHg and 71±48/48±29 mmHg in the other 6 cases without α- blocker preparation. DBPmax and ΔDBP in the prepared group were significantly lower than the unprepared group. Conclusions Most patients with subclinical PHEO have increased catecholamine secretion. Blood pressure is fluctuant greatly during operation in some patients. Patients should be treated with α-receptor blocker preoperatively in order to decrease the operation risk.

Key words: subclinical pheochromocytomas, diagnosis, treatment