The Adrenal Incidentaloma

Today we had a great discussion on the approach to an incidentally discovered adrenal mass.

An adrenal incidentaloma is defined as an adrenal mass (>1cm) that is discovered serindipitously on abdominal imaging designed to look for something else. These are common with an estimated frequency of 6% of the general population.

Imaging characteristics
Many radiographic findings can help determine the malignant potential of a lesion. These include size (>4cm), contrast washout time, density, and border contour of the lesion.

Biochemical Workup
The basic principle is to determine whether the lesion(s) is functional or impairing the function of the gland. See Table 2 in the linked article for some guidelines on workup.

Role of Biopsy
The role of fine needle aspiration in an adrenal mass is primarily useful in determining adrenal from non-adrenal tissue (r/o mets or infection). Actual tissue architecture is required to determine if the lesion is a primary adrenocortial carcinoma. Always remember to r/o a pheochromocytoma (24h urine metanephrines) before asking someone to put a needle into these lesions (hypertensive crisis)

There is an excellent NEJM review here.