Left adrenalectomy, laparoscopic

(1) Adrenal gland, (2) Left kidney, (3) Abdominal aorta (4) Inferior phrenic arteries, (5) Superior suprarenal arteries, (6) Middle suprarenal arteries, (7) Inferior suprarenal arteries, (8) Aberrant accessory renal artery, (9) Renal arteries, (10) Testicular arteries

The paired adrenals are located superior to the superior poles of the kidneys, separated only by a thin layer of fatty tissue. Since they are flattened along the posteroanterior axis, they have clearly distinct anterior and posterior aspects. The left adrenal resembles a crescent, while the right gland is mitral shaped. The anterior aspect of the left adrenal is completely covered with peritoneum, while the latter covers only the inferior aspect of the right adrenal. The posterior aspect of both adrenals abuts the lumbar aspect of the diaphragm.

The topography of the right adrenal relates to the liver and inferior vena cava, while the left adrenal reaches the spleen and is separated from the posterior gastric wall by the lesser peritoneal sac. Both adrenals are located at about the level of the 11^th/12^ththoracic vertebra and enclosed by a vascularized capsule of connective tissue made up of collagen fibers and smooth muscle cells. Adult adrenal glands weigh about five to seven grams.

Blood supply

1. Arteries
Inferior phrenic artery →Superior suprarenal artery
Aorta →Medial suprarenal artery
Renal artery →Inferior suprarenal artery
There are numerous variants!

2. Veins
In each adrenal the venous blood is collected in the central vein which exits the gland through the suprarenal hilum and becomes the left (or right) suprarenal vein.
Right suprarenal vein →Inferior vena cava
Left suprarenal vein →Renal vein

3. Lymphatics

The lymphatics exiting the adrenals primarily parallel the arteries. The primary lymph nodes of the adrenals are the para-aortic and lumbar lymph nodes. Some lymphatics traverse the diaphragm and drain into the posterior mediastinal lymph nodes.

Tumors of the adrenal glands are either primary neoplasias or metastases.

Primary adrenal tumors arise from the adrenal cortex or medulla. Some but not all of them produce hormones.

Adrenal neoplasias actively producing hormones correlate with the corresponding zones in the adrenal cortex or medulla. Tumors of the glomerular zone result in primary aldosteronism (Conn syndrome) and those of the fascicular zone in hyperadrenocortisolism (Cushing syndrome), while neoplasias of the reticular zone produce an overabundance of sexual hormones. Tumors of the adrenal medulla are called pheochromocytomas.

Cortical and medullary tumors of the adrenal gland may be benign or malignant, with the former by far predominant. In cortical tumors the probability of malignancy correlates with the size. In pheochromocytomas there is no such direct relationship between the tumor size and rate of malignancy.

Histological differentiation between benign and malignant adrenal tumors is hampered by their cellular polymorphism and becomes impossible in pheochromocytomas. Here, only the presence of distant metastasis suggests the malignant nature of the tumor.

The gross anatomy of adrenal tumors presents with a homogeneously yellow-brownish cut surface, while pheochromocytomas appear as greyish-red, often also cystic, neoplasias.

Primary tumors of the adrenal glands include myelolipomas, adrenal cysts and ganglioneuromas. Almost without exception these are benign.

Adrenal metastasis is primarily seen in cancer of the lungs and kidneys and in malignant melanoma.

Primary lymphomas are extremely rare.

While the etiology of most primary tumors of the adrenal cortex remains unclear, more than 20% of pheochromocytomas arise from genetic causes (e.g., multiple endocrine neoplasia type 2).