Adrenal incidentalomas (AI) are unsuspected adrenal masses discovered during investigation of unrelated diseases, and are increasing in frequency. The majority of the AI is non-secretory adenomas, although it can also represent primary or metastatic malignant neoplasia. However, less frequent diseases should not be forgotten in the differential diagnosis. We describe a case of a young woman with an adrenal mass without clinical or laboratorial signs of hormonal hyperfunction. Diagnosis was performed after an episode of acute pyelonephritis in which the imaging study was carried out in order to exclude local complications. During the surgical procedure, the fish flesh aspect of the mass raised the suspicion of a neurogenic tumor, which was diagnosed in the histophatological analysis. The patient presented the most common manifestation of adrenal ganglioneuroma, an incidentaloma.