Introduction

Adrenalectomy is the removal of one or both adrenal glands by surgery. The adrenal glands are two in our body and its ia an endocrine glands—one located above each kidney—that produce hormones such as epinephrine, norepinephrine, androgens, estrogens, aldosterone, and cortisol.

The common major pathologic entities of the adrenal gland that require surgical intervention are primary hyperaldosteronism (i.e., Conn syndrome), Cushing syndrome, pheochromocytoma, neuroblastoma, and adrenocortical carcinoma. However, many adrenal glands are removed en bloc as part of a radical nephrectomy for renal cell carcinoma.

Frequently, lesions metastatic to the adrenal gland necessitate adrenalectomy, and finding supports the existence of adrenal excision for symptomatic adrenal cysts. With the tremendous advances in hormonal research the workup of adrenal disorders requiring surgical intervention has undergone a revolution, as well as in radiographic techniques and localization. In general, neoplastic lesions of the adrenal gland may be classified with the node, metastases (TNM) staging system and tumor.

• Node
  • N0 - Negative lymph nodes
  • N1 - Positive lymph nodes
• Metastases
  • M0 - No metastases
  • M1 - Distant metastases
• Tumor
  • T1 - Tumor confined to adrenal gland and less than 5 cm
  • T2 - Tumor confined to adrenal gland and greater than 5 cm
  • T3 - Tumor invasion into periadrenal fat
  • T4 - Tumor invasion of adjacent organs

  TNM Staging System for Neo-plastic Lesions of the Adrenal Gland

  History of the Procedure

  The adrenal gland is crucial to endocrine homeostasis, and maladies associated with it result in several recognized syndromes.

  Problem

  Primary hyperaldosteronism

  The hallmarks of primary hyperaldosteronism are hypertension,hypokalemia, hypernatremia, and elevated urine aldosterone levels (with salt repletion), as well as decreased renin activity and alkalosis with increased urinary potassium excretion. Primary hyperaldosteronism can be secondary to an adrenal adenoma or secondary to bilateral adrenal hyperplasia. To treat them differently, Differentiating between these two disease processes is important. The patient's renin level should also be checked to rule out causes of secondary hyperaldosteronism, such as renal artery stenosis. The renin level is elevated in persons with renal artery stenosis, while the renin level is suppressed in those with primary hyperaldosteronism.

  Adrenocortical carcinoma

  Adrenocortical carcinoma is a rare disease with a poor prognosis. Up to 80% of adrenal carcinomas are functional and secrete multiple hormones.

  Cushing syndrome

  Based on abnormalities of urinary and plasma cortisol and/or adrenocorticotropic hormone (ACTH) the diagnosis of Cushing syndrome is made. The syndrome typically is attributed to central, hypothalamic, or pituitary excess secretion of ACTH (Cushing disease), primary adrenal hypercorticalism, or ectopic secretion of ACTH.

  Myelolipoma

  Adrenal myelolipomas are rare benign masses that consist of fat and hematopoietic cells. Hormonally they are inactive. These masses are typically asymptomatic, but some are associated with flank or abdominal pain. With imaging studies Adrenal myelolipomas can often be diagnosed. On CT scans, myelolipomas appear as well-circumscribed massed with a negative attenuation consistent with fat.

  Pheochromocytoma

  These tumors arise from chromaffin cells of the adrenal medulla. If the tumor arises from a site other than the adrenal, it is termed a paraganglionoma. Paraganglionomas have been found in locations from the neck to the pelvis. Pheochromocytomas also can be a part of an endocrine syndrome such as multiple endocrine neoplasia (MEN) IIa, MEN IIb, von Hippel-Lindau disease, or von Recklinghausen disease.

  Neuroblastoma

  Neuroblastomas arise from sympathetic neuroblasts and occur almost exclusively in the pediatric population. The most common extra-cranial solid tumor in children is represented by Neuroblastoma , and approximately one third of neuroblastomas arise in the adrenal gland. Surgery of neuroblastoma is an important element in diagnosis, staging, and treatment of children with neuroblastoma. Advanced-stage tumors usually require a combination of surgery, chemotherapy, and/or radiation therapy to provide a complete response.

  Frequency

  Tumors of the adrenal cortex are almost all autopsies, with the most common lesion being a benign adenoma. The incidence of adrenal carcinoma is estimated to be 1 case per 1.7 million, and it accounts for 0.02% of all cancers.

  Etiology

  Primary hyperaldosteronism

  The most common causes of aldosterone overproduction are idiopathic adrenal hyperplasia, followed by adenomas, and then (rarely) adrenal carcinoma. Of the benign adenomas, approximately 60% are unilateral (and typically managed surgically), while 40% are bilateral lesions.

  Neuroblastoma

  Neuroblastomas arise from sympathetic neuroblasts and occur almost exclusively in the pediatric population. Approximately one third of neuroblastomas arise in the adrenal gland.

  Pathophysiology

  Primary hyperaldosteronism

  The hallmarks of primary hyperaldosteronism are hypertension, hypokalemia, hypernatremia, and elevated urine aldosterone levels (with salt repletion), as well as decreased renin activity and alkalosis with increased urinary potassium excretion. The most common causes of aldosterone overproduction are idiopathic adrenal hyperplasia, followed by adenomas, and then (rarely) adrenal carcinoma.

  Pheochromocytoma

  These tumors arise from chromaffin cells of the adrenal medulla. Presentation of the pheochromocytoma varies with the production of active metabolites. Most commonly, episodic alpha-adrenergic hypersecretion leads to intermittent malignant hypertension.

  Adrenocortical carcinoma

  As the name implies, adrenocortical carcinoma arises from the cortex. The adrenal cortex in made up of 3 distinct zones: glomerulosa (outer), fasciculata (middle), and reticularis (inner). These 3 zones are responsible for aldosterone, cortisol, and sex steroid production, respectively. Glucosteroids are the most common hormones secreted, followed by androgens, estradiol, and, finally, aldosterone. Adrenal carcinomas can be subclassified according to their ability to produce adrenal hormones.

  Cushing syndrome

  The syndrome typically is attributed to central, hypothalamic, or pituitary excess secretion of ACTH (Cushing disease), primary adrenal hypercorticalism, or ectopic secretion of ACTH.

  Neuroblastoma

  Neuroblastomas arise from sympathetic neuroblasts and in the pediatric population almost occur exclusively. Neuroblastoma represents the most common extra-cranial solid tumor in children, and in the adrenal gland approximately one third of neuroblastomas arise. They are rapidly growing tumors and may be metabolically active; however, the more common presentation is from mass effect.

  Presentation

  Primary hyperaldosteronism

  Presentation of primary hyperaldosteronism includes hypertension, hypokalemia, hypernatremia, and elevated urine aldosterone levels (with salt repletion), as well as decreased renin activity and alkalosis with increased urinary potassium excretion.

  Pheochromocytoma

  Appearance of the pheochromocytoma varies with the production of active metabolites. Pheochromocytoma most often develops in young–to–middle-aged adults. The classic triad is episodic headache, tachycardia, and diaphoresis. Hypertension is the most common clinical sign of pheochromocytoma. Persons with this condition may experience sustained hypertension, paroxysmal hypertension, or sustained hypertension with superimposed paroxysms. Other common signs are palpitations, anxiety, tremulousness, chest pain, and nausea and vomiting. A small group of these patients experience induced myocardiopathy due to sustained catecholamine release. They present with decreased cardiac function and congestive heart failure. Generally, the cardiomyopathy is reversible with the use of antiadrenergic blocking agents and alpha-methylparatyrosine, a catecholamine synthesis inhibitor.

  Adrenocortical carcinoma

  These patients present with constitutional symptoms such as weight loss, fever, and malaise. An increase in sex steroid levels can result in oligomenorrhea, virilization, or feminization.

  The most common presentation of adrenocortical carcinoma is that of an incidentaloma.

  Cushing syndrome

  The clinical presentation of Cushing syndrome is hypertension, moon facies, abdominal striae, buffalo hump, muscle weakness, amenorrhea, decreased libido, osteoporosis, fatigue, hirsutism, and obesity.

  Neuroblastoma

  Neuroblastomas arise from sympathetic neuroblasts and occur almost exclusively in the pediatric population. The most common extra-cranial solid tumor in children is represented by Neuroblastoma, and approximately one third of neuroblastomas arise in the adrenal gland. They are rapidly growing tumors and may be metabolically active; however, the more common presentation is from mass effect.

  Lesions metastatic to the adrenal gland

  It was thought that Adrenal masses arise from distant metastases include melanoma, lung cancer, renal cell carcinoma, and breast cancer. These should be discussed with the primary service taking care of these lesions, but these adrenal masses are often amenable to laparoscopic adrenalectomy.

  Indications

  In deciding whether adrenalectomy is indicated for a newly discovered adrenal mass, one must ascertain whether the mass is functional and if it has signs of malignancy. Except for bilateral adrenal hyperplasia, which can be treated medically with spironolactone, most functional masses should be surgically removed. Signs of malignancy are based on history of carcinoma, tumor size and radiographic findings.

  • History of carcinoma: The most common cancers that metastasize to the adrenal glands are melanoma, lung cancer, breast cancer, and renal cancer. Biopsy of an adrenal lesion is appropriate in a patient with a history of cancer. If the biopsy sample is positive for metastasis, the decision of whether to give chemotherapy, with or without adrenalectomy, should be further explored. In most settings, adrenalectomy would not be indicated in the presence of metastases.
  • Tumor size: adrenal masses larger than 6 cm have a much greater chance of malignancy. Because CT scans tend to underestimate the size of the tumor by more than 20%, the cutoff on CT scan for an adrenal mass should be 4-6 cm. Therefore, adrenal masses larger than 4-6 cm on CT scan are considered high risk for cancer and should be surgically removed.
  • Radiographic findings: Adrenocortical carcinomas and pheochromocytomas have been shown to be hyperintense on MRI T2–weighted images. If the intensity of the adrenal lesion relative to the liver or spleen on an MRI T2–weighted image is less than 80%, the lesion is more likely to be a cortical adenoma. CT scan findings suggestive of an adrenocortical carcinoma include lesions that have irregular margins, are heterogeneous, and have high densities on non contrast images. Necrosis and calcification are also more commonly associated with adrenal carcinoma. Most adenomas are lipid rich and have densities of less than 10 Hounsfield units.

  Attention must be given to the increasing diagnosis of the adrenal incidentaloma, which refers to a clinically in apparent adrenal mass that is discovered with some form of imaging study performed for an indication not related to adrenal disease. In general, adrenal incidentalomas associated with abnormal hormonal findings should undergo surgical adrenalectomy. If a mass is nonfunctional and has no signs of malignancy (i.e., >6 cm), the patient can be monitored and observed. The patient should undergo CT scanning every 6 months and an annual endocrine evaluation for 4 years. If the mass grows or affects endocrine function, it should be removed.

  Relevant Anatomy

  Understanding the anatomy of the adrenal glands is essential before describing surgical technique. Both adrenals are located on the superior posterior aspect of the kidneys in the retroperitoneum. The right adrenal is covered anteriorly by the liver and has a short vein typically draining directly into the inferior vena cava (IVC). The left adrenal is covered anteriorly by the pancreas and spleen. In general, the surgical approach is dependent on the primary adrenal lesion, the size of the lesion, the side of the lesion, and the habitus and health of the patient, as well as surgeon preference and familiarity.

  Contraindications

  Metastatic disease, unless part of research protocol, is a contraindication to adrenal surgery.