Diagnostic pitfalls of adrenal incidentaloma

Adrenal incidentaloma (AI) includes all lesions with diameter ≥ 1 cm found incidentally during imaging examinations not associated with suspected adrenal pathology. Every adrenal incidentaloma requires a detailed hormonal and imaging assessment. Initial diagnosis includes radiological phenotypical evaluation (particularly in CT, or in case of contraindications - in MRI) and biochemical assessment of tumour hormonal activity (which includes cortisol circadian rhythm, salivary cortisol concentration, 24-hour urinary free-cortisol and metanephrines test, short cortisol and dexamethasone suppression test, ACTH level assessment, aldosterone and ARO concentration, adrenal androgen concentration). Each diagnostic step is associated with limitations and method imperfections. The influence of administered medications, age and concomitant diseases must be taken into account when interpreting test results. It is important to remember abovementioned factors may cause false positive or false negative test results. The following paper is to summarize the etiology of the most common diagnostic mishaps which frequently lead to misdiagnoses, an increase in patient's anxiety and, as a consequence, in the introduction of improper therapy or its discontinuation. The awareness of biochemical and imaging test limitations, and the knowledge of false positive and false negative result sources, allows for the optimisation of the diagnostic process. Simultaneously, the analyzed factors may contribute to a decrease in unnecessary and frequently repeated tests. Additionally, it may imply avoiding the costs of unjustified deep diagnostics.