Endocrine Abstracts

JOINT3515

Introduction: Pheochromocytoma are neuroendocrine tumors originating from chromaffin cells of the adrenal medulla or extra-adrenal paraganglia. The aim of this study was to compare clinical and radiological characteristics of normetanephrine- and metanephrine secreting pheochromocytomas.

Subjects and Methods: This retrospective single-center study included 12 patients with confirmed pheochromocytoma followed up at the outpatient clinic of the endocrinology department in Tunis Military Hospital. Clinical and paraclinical data were extracted from patients’ medical records. Patients were divided into two groups: Group 1 (n = 6) with normetanephrine-secreting tumors, defined as normetanephrine level more than 3 times the normal limit and Group 2 (n = 4) with metanephrine-secreting tumors, defined as metanephrine level more than 3 times the normal limit. Two mixed-secretion cases were excluded.

Results: The median age (IQR) at diagnosis was 45 (29 – 65) years in the first group and 58 (37 – 74) years in the second group (P = 0.257). Clinical presentation included paroxysmal hypertension (2 cases in each group), permanent hypertension (G1: 4 vs G2: 1), resistant hypertension (G1: 2 vs G2: 1) and Menard triade (G1: 4 vs G2: 3). No significant difference was noted in the two groups. Adrenal incidentaloma was the circumstance of discovery in all cases in group 1 and 3 cases in group 2. Median heart rate was 82 bpm (IQR:74 – 105) in group 1 and 76 (IQR:68 – 106) in group 2 (P = 0.476). Median blood pressure during crisis was 190/105 mmHg in group 1 (P = 0.393) and 180/100 in group 2 (P = 0.629). Complications were present in 3 cases in the first group and 2 cases in the second group. They included albuminuria (1 vs 2, P = 0.524), ventricular hypertrophy (1 case in each group), hypertensive retinopathy (2 vs 1, P = 1.000), haemorrhagic stroke and myocardial infarction in 1 case in group 2. Radiological findings showed a median size of 57 mm (IQR:48 – 68) in group 1 vs 50 mm (43 – 68) in group 2 (P = 0.762). Median washout was 28% (IQR:21 – 39) in group 1 and 45% in group 2 (P = 0.610). All normetanephrine tumors were heterogeneous, vs 3 (75%) of the other group. Left location of the tumor was more frequent in both groups. All patients had adrenalectomy. One patient had persistent hypertension postoperatively. However, the number of antihypertensive drugs decreased from 3 to 1.

Conclusion: This study found no significant differences between normetanephrine- and metanephrine-secreting pheochromocytomas. Due to the rarity of these tumors, further large-scale studies are needed to validate these findings.