Adrenal Gland - Pathology

2021-02-21 12:00 AM

Cushing syndrome is characterized by increased levels of glucocorticoids.

ADRENAL GLAND

Cushing syndrome is characterized by increased levels of glucocorticoids. It is investigated with lab and imaging studies. The most common cause is exogenous glucocorticoid administration.

 Endogenous causes include:

  •  Cushing disease (hypersecretion of ACTH, usually due to a pituitary micro-adenoma)
  •  Secretion of ACTH from nonpituitary tumours (e.g., small cell lung cancer)
  •  ACTH-independent Cushing syndrome due to adrenal neoplasia

Clinical manifestations include hypertension, weight gain (truncal obesity, “buffalo hump” and moon facies), cutaneous striae, hirsutism and mental disturbances.

Hyperaldosteronism may cause hypertension and hypokalemia.

  •  Primary (decreased plasma renin)
  •  Adrenocortical neoplasm: adenoma (Conn syndrome)

 ■  Circumscribed yellow nodule with vacuolated cells

 ■  Carcinoma: poorly demarcated lesion with cystic change and pleomorphic cells

 °°   Bilateral nodular hyperplasia of the adrenal

  •  Secondary (increased plasma renin) (e.g., renal artery stenosis)

 Adrenogenital syndromes are adrenal disorders characterized by excess production of androgens and virilization. They are caused either by adrenocortical adenoma/ carcinoma, which produces androgens or by congenital adrenal hyperplasia, a cluster of autosomal recessive enzyme defects (most common is 21-hydroxylase deficiency).

Waterhouse-Friderichsen syndrome (acute adrenal insufficiency) is a potentially fatal, bilateral hemorrhagic infarction of the adrenal glands associated with sepsis, often due to a N. meningitides infection in children. It is clinically characterized by disseminated intravascular coagulation (DIC), acute respiratory distress syndrome, hypotension and shock, and acute adrenal insufficiency. Treatment is antibiotics and steroid replacement.

Addison’s disease (chronic adrenocortical insufficiency) is caused by the destruction of the adrenal cortex, leading to a deficiency of glucocorticoids, mineralocorticoids, and androgens. The most common cause is autoimmune adrenalitis, though adrenal involvement by TB or metastatic cancer is other possible causes. Patients present with gradual onset of weakness, skin hyperpigmentation, hypotension, hypoglycemia, poor response to stress, and loss of libido. Treatment is steroid replacement.

Secondary adrenocortical insufficiency may be caused by disorders of the hypothalamus or pituitary (cancer or infection, for example). Since ACTH levels are low, hyperpigmentation does not occur.

Pheochromocytoma (“dark/dusky-coloured tumour”) is an uncommon benign tumour of the adrenal medulla, which produces catecholamines (norepinephrine and epinephrine). It can present with sustained or episodic hypertension and associated severe headache, tachycardia, palpitations, diaphoresis, and anxiety. Note the rule of 10s:

  • 10% occur in children
  • 10% are bilateral
  • 10% are malignant
  • 10% are familial (MEN 2A and 2B)
  • 10% occur outside the adrenal gland

Urinary vanillylmandelic acid (VMA) and catecholamines are elevated. Microscopically, the tumour shows nests of cells (Zellballen) with abundant cytoplasm. Treatment is control of the patient’s BP and surgical removal of the tumour.