Nodular adrenal disease is a frequent occurrence in common clinical practice. It has undergone a notable increase due to the diffusion of diagnostic imaging performed for different clinical problems. Although the incidental finding of an adrenal incidentaloma occurs from the middle age, epidemiologically these lesions are more frequent in old age. Most are non-secreting adenomas but some of them may be characterized by a different hormonal activity. On the contrary, the adrenal malignant forms are the minor part. In addition to adrenal incidentaloma, the adrenal nodule, diagnosed during the follow-up of patients with previous neoplastic disease, need a differential diagnosis for the risk of being metastases.
This study aims to evaluate morphological and functional characteristics of adrenal nodules diagnosed in a series of patients previously affected by malignant tumors. Preliminarly, in a cohort of patients with these characteristics, will be evaluate hormone levels according to current protocols of study for the adrenal nodule and a basal and dynamic CT study. Finally, all those non-secreting nodules with high basal values of HU and relative and absolute wash out suspected for malignancy will be studied with 18F-FDG-PET.
As previously noted, the discovery of an adrenal mass, either it occurs accidentally or in a follow-up program, is not unusual and this occurrence increases with the age of the patient. It should be remembered that many benign adrenal diseases involve both glands. In fact, in 15% of patients with bilateral incidental masses, they appear to be the cause of bilateral congenital hyperplasia and ACTH-independent bilateral macronodular adrenal hyperplasia (BMAH). However, the adrenal glands, are often involved in the process of metastasizing from a wide range of tumors with different histotypes, originating from many organs. According to current literature, the frequency of adrenal metastases in oncological patient with an adrenal lesion is around 50-75%. In some cases, the primary neoplasm causing the metastasis is not known: it has been observed that this occurs in about 5.8% of cases when lesions are found in both adrenal glands, while this occurrence drops drastically to 0.2% if only one adrenal gland is affected. However, these data derive from retrospective series and and are characterized by an underestimated sample size. The consideration that is currently attributed to these data could contain some pitfalls. The greatest risk is to misdiagnose a benign primary adrenal lesion with adrenal metastasis. This could mistakenly lead to consider that as a recurrence. Further risks are represented by the possibility of an adrenal mass biopsy which in most cases would not be diagnostic or, worse, would cause a hypertensive crisis in the case of a pheochromocytoma or neoplastic spread in case of adrenocortical carcinoma. It would result in a useless repetition of the biochemical and radiological investigations if not indeed of unsuitable therapy with an increase in patient concern and a considerable waste of economic resources. Therefore, we hope that this prospective study, through the use of multiple methods, will lead to the identification of a flow-chart in this particular patient setting.