Endocrine Abstracts

Introduction: Pheocromocytomas represent a rare clinical entity with an incidence of approximately 0.8 per 100 000 person-years. Due to their rarity, the characteristics of patients with pheochromocytoma have not been thoroughly investigated yet.

Aim: The assessment of pre- and post-operative clinical and biochemical characteristics as well as the evaluation of imaging and histological data of patients with pheochromocytomas.

Design: Observational retrospective study of patients diagnosed with and treated for a pheochromocytoma in a tertiary general hospital between 2012 and 2022.

Methods: Medical records of patients with pheocromocytoma were reviewed and parameters related to patients’ metabolic status (BMI, fasting glucose, HbA1c, total cholesterol, triglycerides, HDL, LDL), as well as pheochromocytoma characteristics [tumor size on imaging, 24 h urinary metanephrine (UMN) and normetanephrine (UNM) levels, phenoxybenzamine total daily dose (TDD) and total cumulative dose (TCD), histology PASS score] were recorded. In addition, comparison of patients’ metabolic parameters (lipids and fasting glucose levels) at diagnosis and after surgical removal of the pheochromocytoma was performed.

Results: Overall, 48 consecutive patients (50% females, mean age 48±15 years) with pheochromocytoma, diagnosed and surgically treated in our hospital, were included. Pheochromocytomas were incidentally detected in 46% of the patients, 57.4% were hypertensive (33% paroxysmal), 17% diabetic, 17% obese and 51% were symptomatic. At baseline assessment, no significant differences were found regarding the metabolic and tumor parameters between obese and non-obese patients, overweight and non-overweight ones, as well as between patients with incidentally detected pheochromocytoma and those presented with secondary hypertension or pheochromocytoma-related symptoms. Interestingly though, diabetic patients had larger tumors (P=0.048) compared to those without diabetes. Regarding preoperational treatment symptomatic patients (P=0.013) required significantly higher TDD of phenoxybenzamine than asymptomatic patients. Univariate correlations demonstrated significant positive associations between UMN and both phenoxybenzamine TDD (P=0.025) and TCD (P=0.05). Larger tumors were associated with higher PASS scores indicating a more aggressive histology (P=0.007). Twenty patients were followed-up after adrenalectomy for a mean period of 36±21 months. Follow-up assessment showed a significant improvement in fasting glucose values after pheochromocytoma resection (P=0.001), whereas lipid profile was not affected.

Conclusion: Our study demonstrates that the pheochromocytoma-associated metabolic alterations of glucose homeostasis improve after surgical removal of the tumor. Furthermore, tumor size seems to be a significant predictive factor of tumor aggressiveness.