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Character-Normal

The normal adrenal gland is soft and friable. It is usually surrounded by fatty tissue and is encapsulated. The surface appears corrugated or nodular and is usually not smooth.

The normal color is a golden yellow color which can be distinguished from the more pale surrounding fat. The capsule is a thin fibrous structure surrounding the gland attached by many fibrous bands which penetrate into the gland.

When the adrenal is cut, the outer cortex and the inner medulla can be distinguished by color. The cortical (outer) layer appears golden yellow while the inner medulla appears more flattened and a darker reddish/brown.

The outer cortex has separate embryological origin and is distinct in its function and structure. The hormones produced by the cortex have a steroid infrastructure. The inner medulla which only accounts for 10% by weight produces catecholamines.The cortical (outer) layer appears golden yellow while the inner medulla appears more flattened and a darker reddish/brown.Courtesy of: Ashley Davidoff, M.D.
The adrenal glands behave like other parenchymal organs on CT scanning in that they are of soft tissue density. Under physically stressful situations, they may enhance significantly more than other organs due to their rich blood supply.Courtesy of: Ashley Davidoff, M.D.
On T1-weighted imaging, the intensity of the adrenals is less than that of the surrounding liver and spleen. While on T2-weighted imaging, the adrenal is usually close to the intensity of the liver.Courtesy of: Ashley Davidoff, M.D.

Incidentaloma

An “incidentaloma” is the most common adrenal tumor. It represents a small benign adenoma, (“oma” = tumor) of no functional significance, which is found incidentally, and hence its name. A nodule that is less than 3cm. with a density of less than 10 HU on CT, is diagnostic of the “incidentaloma”. The characteristic finding on MRI is a darkening in the “out of phase” T1 sequence of the tumor .

In this CT scan, the green overlay is a soft tissue nodule that was found incidentally.Courtesy of: Ashley Davidoff, M.D.

 

The nodule is oval, with smooth borders, measures less than 3cm., (left image) and has a density of 2.6 HU. (right image) It is a classical “incidentaloma” or benign adenoma. No further workup is needed.Courtesy of: Ashley Davidoff, M.D.

Calcification in the Adrenal Glands

 

This coned down plain film of the abdomen details bilateral adrenal calcification. Note that in this instance, the right adrenal gland is slightly higher than the left.
Courtesy of: Ashley Davidoff, M.D.

The most common cause of adrenal calcification is:

hemorrhage (occurring in the perinatal period) or

trauma.

Other less common entities producing calcifications in the adrenal include:

·         histoplasmosis

·         neuroblastomas

·         tuberculosis

Uncommon causes include:

·         Addison’s disease

·         amyloidosis

·         Cushing’s syndrome

·         cysts

·         neoplasms

·         pheochromocytomas

The idiopathic causes have no known etiology.