Endocrine Abstracts

Introduction: The majority the pheochromocytomas (PCCs) are diagnosed incidentally. The absence of characteristic paroxysmal symptoms does not exclude the diagnosis. The purpose of this study is to evaluate the diagnostic sensitivity of imaging features and biochemical markers in PCCs, providing data to improve clinical decision-making.

Methods: The available imaging results, clinical and biochemical data of patients who underwent laparoscopic adrenalectomy at our institution from January 2015 to May 2024 with histopathological diagnosis of PCC were collected and retrospectively analyzed. The sensitivity of imaging features was calculated based on the available results, and not all patients had information regarding every specific feature.

Results: Among 52 patients (52% female) included, 92% were primarily diagnosed with adrenal incidentaloma. 2 patients were diagnosed with bilateral PCCs. Radiologic anatomical examinations included computed tomography (CT) and/or magnetic resonance imaging (MRI) revealing a median tumor size of 38.5 mm (range 15-82 mm). On CT scans lesions had attenuation of >10 HU (median 33 HU; range 15-50 HU) or were heterogeneous. Median enhancement in portal venous phase was 72.5 HU (range 37-170 HU). The sensitivity of an absolute wash-out <60% was 91% (20/22). Additional features were heterogeneous enhancement after contrast and cystic/necrotic components with sensitivity of 32% (16/50), respectively. Key findings on MRI scans included heterogeneity (sensitivity of 50%, 14/28), no loss of signal in T1 out-of-phase sequence (39%, 11/28), heterogenous and elevated enhancement after contrast (36%, 10/28 and 39%, 11/28, respectively), restricted diffusion (46%, 13/28), cystic component (39%, 11/28), and high signal on T2 (14%, 4/28). Elevated metanephrine and normetanephrine in urine correlated with lesion size. Normetanephrine showed higher sensitivity (87.0%) than metanephrine (60.9%), with a tendency of predomination of one of the metabolites.

Conclusion: The diagnosis of pheochromocytoma must be based on a comprehensive analysis of the imaging findings. Features indicating heterogeneity and cystic or necrotic components in correlation with biochemical data are crucial for optimizing treatment planning, including surgical intervention.