Adrenal Tumors in Children
Scott J. Revell
Carly M. Conway
Jessica L. Buicko
The first successful adrenalectomy was performed by John Knowsley Thornton who removed a 20-lb en bloc adrenal tumor with left kidney from a 36-year-old woman in 1889.
Since that time anterior, posterior, thoracoabdominal, and laparoscopic approaches have been developed for both the benign and malignant pathologies.
The adrenalectomy has become the treatment mainstay for adrenal hyperplasia, large nonfunction adrenal tumors, benign endocrinologically active or enlarging adenomas, adrenal cancers, and adrenal metastasis.
The adrenal glands are triangular dark yellow structures located superior and medial to the kidneys in the retroperitoneum at the level of the 11th thoracic vertebrae.
The adrenal gland is composed of 2 independent exocrine organs made up of tissue from different embryological origins, the outer cortex, and the inner medulla.
The adrenal cortex is divided into 3 layers, each dedicated to its synthetic function.
The outermost layer that is composed of steroid-producing cells of the zona glomerulosa is devoted to synthesis of mineralocorticoids and makes up 15% of the adrenal gland.
The zona fasciculata devoted to glucocorticoid production makes up 75% of the gland.
The zona reticularis synthesizes and secretes androgens.
The medulla arises from neuroectoderm and contains the Chromaffin cells, which produce the catecholamines: norepinephrine and epinephrine.
The adrenals are highly vascular and receive arterial supply from 3 sources.
Superiorly they receive multiple branches from the phrenic arteries.
The medial aspect is supplied by the direct aortic perforator, and inferiorly small branches originate off the renal arteries.
Care must be taken to identify and cauterize these small branches to prevent bleeding.
The venous outflow from the adrenals occurs via a single dominate vein.
On the left, it drains into the left renal vein.
EPIDEMIOLOGY AND ETIOLOGY
Adrenal tumors other than the neuroblastoma occur rarely in childhood.
Neuroblastoma, covered in chapter 48, is the most common adrenal tumor and may occur anywhere along the sympathetic nervous system, with 40% originating in the adrenals.
Neuroblastoma is the most common extracranial solid tumor diagnosed in the pediatric population accounting for 8% to 10% of all childhood malignancies and 15% of pediatric cancer deaths.
With an incidence of 1/100 000 persons-years, they account for more than 90% of adrenal tumors.2
Tumors derived for the adrenal cortex are uncommon and account for only 0.2% of malignancies in the US pediatric population.3,4
There is an increased incidence associated with several genetic syndromes including Beckwith-Wiedemann, Li-Fraumeni, multiple endocrine neoplasia-type 1, and familial adenomatous polyposis coli, which has led to investigations examining oncogenes and tumor suppressor genes, yet the exact etiology remains elusive.5,6
The other neoplasm discussed in this chapter is the pheochromocytoma (PCC), which originate from adrenal chromaffin cells of the medulla.
Within the pediatric population, the estimated incidence of PCC and paragangliomas (extra-adrenal PCC) is 0.8 to 1.6 per million.7,8,9,10
Roughly 80% of these tumors will produce catecholamines, and PCC may account for up to 90% of the pediatric population with sustained hypertension.8
Adrenal Cortical Tumors
Adrenal carcinomas are extremely aggressive tumors, and a good prognosis largely depends on early detection.
Approximately 90% of adrenal cortical tumors (ACTs) in children are functional, producing androgens, cortisol, aldosterone, estrogen, or a combination of steroids.
About 80% of these tumors produce androgens making the sequalae virilization the most common presenting signs.
Presenting signs and symptoms depend on age and sex.
Female infants are likely to present with ambiguous genitalia such as fusion of the labioscrotal folds, clitoromegaly, or external male genitalia with bilateral cryptorchidism.
The signs in male infants will be more subtle, likely presenting as penile enlargement and accelerated growth as the child ages.
In older children, hirsutism, accelerated growth, short stature due to premature closure of growth plates, early acne, amenorrhea (primary and secondary), clitoromegaly, and precocious puberty should prompt investigation.11
It is important to note that congenital adrenal hyperplasia (CAH) is the most common cause of virilization and ambiguous genitalia in newborns.
Roughly 90% of cases are caused by defects in 21-hydroxylase, leading to improper synthesis of cortisol and aldosterone and shunting of steroid precursor molecules to the androgenic intermediaries.
CAH can be differentiated from virilizing tumors by administering dexamethasone 0.5 mg po q 6 hours for 48 hours, which will suppress urinary and plasma excess androgens in cases of CAH.
Additionally, CAH exhibits concomitant glucocorticoid and mineralocorticoid deficiencies.
Cushingoid features secondary hypercortisolism is another common presentation.
In the pediatric population, impaired linear growth is an important sign of hypercortisolism.
Signs common in adults are common in children as well.
The redistribution of fat to the upper back and face is pathog-nomonic, but central obesity, hypertension, easy bruising, osteoporosis, striae, acne, and menstrual irregularity should all prompt investigation.
Adrenal cortical carcinoma is a very aggressive tumor, which metastasizes to the lungs, liver, and lymph nodes.
Prognosis is based on size and resectability.