A study of pheochromocytoma 34 cases.

A twenty years (1976-1995) retrospective study was undertaken of 8,768 cases hypertensive patients who were admitted to Siriraj Hospital, with pheochromocytoma in 34 cases (0.39%). The latter group comprised of nine males (26.5%) and 25 females (73.53%), giving a male:female ratio of 1:2.8 their aged range were 7-59 years (mean 34.12 years). Most of the patients presented with cardinal symptoms:headache, diaphoresis and palpitation plus other minor symptoms. Wit the exception of one patient whose blood pressure was high (mean arterial pressure = 148+ 18 mm. Hg) and unstable from 110/70 to 270/170 mm. Hg during the 24 hours recorded. The investigations for the etiology were divided into two periods The first period was from 1976 to 1982. A phentolamine test was performed in 11 cases, with positive results. The investigations then continued with perirenal air insufflations and adrenal angiography, which gave results of tumour masses in the adrenal glands. The investigations during the second period from 1982-1995 were comprised of the measurements of plasma catecholamine in 12 cases, and 24 hours urine cetechalamine, and vanillyl mandelic acid (VMA) in 18 and 17 cases respectively. The means levels of plasma catecholamine, urine catecholamine4 and urine VMA were 7.5+ 8 μg/L (normal < 1.5 μg/L), 255.8+ 181.4 μg (normal < 15 μg) and 51.2+ 27.7 μg (normal = 1.5-10 μg) respectively. These values were higher than normal especially for urine catecholamine but these values significantly returned to normal after operation in the cases of benign pheochromocytoma. CT scan and metaiodobenzylguanidine (MIBG) were ten performed in 21 and 2 cases respectively with the demonstration of sites and sied of tumour masses in the adrenal glands in 19 cases and extraadrenal in 2 cases, of the latter, one patient had a tumour mass which was seated in front and had invaded the inferior vena cava, while the second patient was found to have a tumour mass on the Zackerkandl gland. Another two cases of Zuckerkandl were detected by surgery. These four extra adrenal tumours were observed. The α adrenergic blocking drug of choice for control blood pressure before surgery in the first period was phenoxybenzamine (20-80 mg/day) while the second period the drug of choice was a post synapic α1 adrenergic blocking drug (prazosin) which was used until blood pressure was well controlled. The started dose was 2 mg of prazosin and increasing to not more than 20 mg/day. Aβ adrenergic blocking drug (propranolol) was administered orally for control of the pulse rate when it increasing duringα adrenergic drug was given. When both blood pressure and pulse rate of the patients treated during the two period was controlled, surgery was performed with the results of 30 benign tumours (88.24%) size 1 x 1.2 – 16 x 15 x 8.5 cm )mean 5.54 x 4.83 x 4 cm) and 4 malignants (11.76%). One patient died (2.94%) during the operation as a result of massive haemorrhage following the surgery, benign pheochromocytoma patients showed a cure rate of 100 percent without requiring any antihypertensive drugs. The four cases of malignant tumour had to be treated with high dose of prazosin, with two cases also received palliative e radiotherapy treatment resulting a temporary reduction the size of the tumour was achieved. One patient who was a regular attendance at the hypertension clinic survived for 12 years.