Adrenal Gland Pathology PDF

Adrenal gland pathology By Dr- Husam-Eldin Omer Introduction Histologically the adrenal gland consists of two different areas, cortex and medulla. The medulla which is the inner area is classified as part of the sympathetic nervous system. It secrets catecholamines, which are essential in the...

Adrenal gland pathology By Dr- Husam-Eldin Omer Introduction Histologically the adrenal gland consists of two different areas, cortex and medulla. The medulla which is the inner area is classified as part of the sympathetic nervous system. It secrets catecholamines, which are essential in the physiological responses to stress.e.g. infection, shock or injury The cortex can be divided Histologically into three zones. Directly beneath the capsule lies the zona glomerulosa. This zone produces mineralocorticoid steroids such as aldosterone which acts on the renal tubules to increase reabsorption of sodium and chloride, reducing their loss in urine at the expense of potassium exchange. The synthesis and release of aldosterone is not under pituitary control. It is regulated by.renin-angiotensin system Zona fasciculata is the middle zone. It is rich in lipid. It produces glucocorticoids. The inner zone is named zona reticularis..It produces androgen precursors (mostly Dehydroepiandrosterone DHEA beside some androstenedione). The produced sex steroids of this zone is low in normal adult compared with that in the gonads and may not be physiologically.important The glucocorticoids have important effects on a wide range of tissues and organs. At physiological levels they mainly do the ;following metabolic activities Inhibit protein synthesis. * * Increase protein breakdown..* Increase gluconeogenesis The pathological problems of adrenal cortex There are the hyper and hypo function disorders beside the problems of the tumors Hyper function problems: The nature of these problems depends on whether mineralocorticoids, glucocorticoids or sex steroid are produced in excess Hyper aldosteronism Generally the high aldosterone results in renal retention of sodium & water and leads to hypertension. The corresponding loss of potassium may lead to muscular weakness & cardiac arrhythmias and the associated metabolic alkalosis may cause tetany & paraesthesiae. Plasma and urine aldosterone are both high. There are two types Primary (Conn`s disease) (1 The usual cause is an adenoma of the zona glomerulosa, but generalized autoimmune primary hyperplasia sometimes is responsible. Renin is low. There is no specific age or gender but it often between 30 to 50 years 2) Secondary Hyper aldosteronism It is secondary to increase in rennin secretion which may occur in conditions in which there is reduction in renal glomerular perfusion e.g. during the severe hypovolaemia. Occasionally a rennin secreting tumor may be the cause without a reduction in renal glomerular perfusion. Rennin serum level is high in secondary hyper.aldoseronism but it is low in primary Cushing's syndrome It is a group of clinical symptoms and sings which occur due to excessive circulating glucocorticoids. The syndrome occurs most commonly in women, but may present in men and rarely in children. The increased protein breakdown leads to loss of muscle.bulk particularly on the limbs The centripetal deposition of fat results in moon face, buffalo hump and trunk obesity. The inhibition of protein synthesis and the abnormal collagen maturation cause abdominal striae. Osteoporosis may occur and it may lead to vertebral collapse. Wound healing may be delayed. The cross hormonal action to insulin causes diminishing in glucose tolerance with frank diabetic state in about 20% of cases. Sometimes Hypertension, and mental symptoms like depression & psychosis may follow. Glucocorticoids excess is demonstrated either by the elevated plasma levels of cortisol (but is not specific ) or by the elevated urinary excretion of 17- hydroxysteroids (24 hours urinary cortisol) which is specific and diagnostic to all causes of Cushing syndrome. The cause of this syndrome either to be iatrogenic or natural pathology. Iatrogenic cause is relatively common and it occurs by administration of high doses of glucocorticoids. The three clinical forms of the natural ;pathology group are the following Excess ACTH secretion by a functioning* pituitary adenoma (Cushing's disease) * Adrenal cortical neoplasm. * Ectopic ACTH secretion e.g. CA lung Excess ACTH secretion by functioning pituitary adenoma is the commonest cause in the natural group. It named Cushing's disease because it was described for the first time by a doctor called Harvey William Cushing. It leads to.bilateral adrenal cortex hyperplasia Hyper secretion of cortisol by a tumor of the corticotrophs This is the main cause of Cushing's syndrome in children. The neoplasm is usually an adenoma. In few adult cases a carcinoma may be the cause. These tumors secrete cortisol.autonomously & independently of ACTH The ACTH level is typically low. Excess secretion of androgens may occur at the same time with the excess cortisol. This is more prominent in cases of adrenal cortex carcinomas of adults. Adenoma of adults is often non functioning, unlike that of children Ectopic ACTH secretion ACTH level is high with bilateral adrenal cortex hyperplasia. adrenogenital syndrome As mentioned before, this condition may be associated with all causes of Cushing syndrome but it is more common in adrenal carcinoma. In adult female the excess tumor secretion of androgens causing hirsutism, amenorrhoea, and virilization The prognosis is poor in case of adrenal carcinoma. It is quite difficult to differentiate between adrenal adenoma and carcinoma if there is no metastasis. However if the adrenal neoplasm is large (>100 g), and it secretes androgens, it is most likely to be a carcinoma. Males children with a secreting cortical adenoma may show precocious puberty with Cushing syndrome at once time. However precocious puberty may occurs without Cushing syndrome when there is a congenital enzymatic defect in cortisol synthesis. Here an excess ACTH secretion will occur trying to compensate the low cortisol level. So the end result will be over stimulation and production of androgen hormones. Cushing syndrome abdominal striae  Cushing syndrome trunk obesity, moon face, buffalo hump, wasting limbs Adrenocortical hypofunction: This is usually due to a pathological cause which involve the whole cortex and end with lack of both mineralocorticoids and glucocorticoids (Reduction in both cortisol and aldoserone). It can be primary, due to a lesion within the adrenal gland, or secondary due to failure of ACTH secretion by the adenohypophysis. The primary form either to be acute, which is called Waterhouse friderichsen syndrome, or to be chronic. In both of these two situations the ACTH is high. The acute primary form there is acute hemorrhagic necrosis of the adrenals due to meningococcal septicemia or other acute septicemias. Severe algid malaria and DIC are other known causes. This - necrosis causes very dangerous hypo.volaemic shock and severe hypoglycaemia The chronic primary form is named Addison's disease. It may affect any age of the two gender but it mainly involves adults between 30 to 50 years. It follows diseases like destructive autoimmune adrenalitis ,tuberculosis, amyloidosis, and haemochromatosis. It may also caused by the metastatic tumors or associated to adrenal atrophy which occurs following prolonged steroid therapy. The main clinical features include the hypotension, lethargy, muscle weakness and anorexia. The pigmentation of skin (tanned skin) and mucous membranes is due to the high ACTH. Corticotropin (ACTH) can be cleaved to form α melanocyte stimulating hormone (α-MSH).that stimulates the production of melanin The microscopic appearance of the adrenals with meningococcemia and acute adrenal insufficiency..There is marked hemorrhagic necrosis Addisson disease Tanned skin The pathological problems of the adrenal medulla The main two problems are the phaeo- chromocytoma and neuroblastoma and both of them are tumors. Phaeochromocytoma: It is a benign tumor which is classified as a paragan- glioma. It is derived from the medull- ary chromaffin cells. This tumor presents through the effects of its catecholamine secretions. The tumor Brown, solid, usually less than 5 cm in diameter and it may be familial, assoc- iated with medullary carcinoma of the thyroid or with hyperparathyroidism as part of multiple endocrine neoplasia (MEN) syndrome. The main clinical features are the hypertension which is sometimes intermittent. It is due to the peripheral vasoconstriction, pallor,.headaches, sweating and nervousness The diagnosis is based on estimating urinary excretion of vanillyl mandelic acid (VMA) beside the abdomen computerized - tomography (CT scanning) and radio.isotope scanning - Neuroblastoma: Is the most common cancer in infancy and the most common extracranial solid cancer in childhood. It derived from sympathetic nerve cells and  It secretes catecholamine. It is highly malignant tumor that often presents as a the large abdominal mass. On microscopy, tumor cells are typically small, round,.blue, & often form rosette pattern Rarely benign tumors may arise from the adrenal medulla like neurofibroma, ganglioneuroma, fibroma and angioma  Neuroblastoma The tumor cells are small, round, blue forming rosette pattern  Neuroblastoma Large abdominal mass