Comparison of the Clinical and Biochemical Parameters Between Cystic and Non-Cystic Pheochromocytoma.

INTRODUCTION: There are limited literature studies and awareness regarding the clinical and biochemical characteristics specific to cystic pheochromocytomas. This study aims to comprehensively assess clinical and biochemical characteristics of cystic pheochromocytomas and compare them with non-cystic counterparts. METHODS: Based on pre-operative computed tomography (CT) imaging, patients were divided into two groups. Group 1 comprised patients with predominantly cystic pheochromocytoma, defined by the presence of >50% cystic component within the tumour volume. Group 2 included patients with non-cystic pheochromocytoma. RESULTS: A total of 46 patients with histopathologically confirmed pheochromocytoma were analysed, of which 8 (17.4%) were cystic and 38 (82.6%) were non-cystic. There were no differences in demographic and clinical parameters between the two groups. However, patients with cystic tumours had significantly lower prevalence of elevated plasma normetanephrine levels (37.5% vs. 85.7%, P = 0.005), suggesting a lower catecholamine secretory burden. Cystic pheochromocytoma more frequently occurred on the left side (85.7% vs. 29.4%, P = 0.03) and had lower baseline CT attenuation than non-cystic pheochromocytoma (31.3 ± 8.2 vs. 39.25 ± 7.6, P = 0.03). CONCLUSION: Cystic pheochromocytomas may represent a distinct subtype with lower biochemical activity. Their identification requires careful radiological assessment, especially in biochemically negative patients. Enhanced awareness of their characteristics may improve diagnosis and optimise surgical outcomes.