Page 815 - Textbook of Pathology, 6th Edition

SECONDARY ADRENOCORTICAL INSUFFICIENCY workers. Occasionally, a cortical adenoma may be a part of 799
multiple endocrine neoplasia type I (MEN-I) in which
Adrenocortical insufficiency resulting from deficiency of patients have associated adenomas of parathyroid, islet cells
ACTH is called secondary adrenocortical insufficiency.
and anterior pituitary (page 829).
ETIOPATHOGENESIS. ACTH deficiency may appear in
2 settings : MORPHOLOGIC FEATURES. Grossly, an adenoma is
1. Selective ACTH deficiency due to prolonged administration usually a small, solitary, spherical and encapsulated
of high doses of glucocorticoids. This leads to suppression tumour which is well-delineated from the surrounding
of ACTH release from the pituitary gland and selective normal adrenal gland. Cut section is typically bright
deficiency. yellow.
2. Panhypopituitarism due to hypothalamus-pituitary Microscopically, the tumour cells are arranged in
diseases is associated with deficiency of multiple trophic trabeculae and generally resemble the cells of zona
hormones (page 794). fasciculata. Less frequently, the cells of adenoma are like
those of zona glomerulosa or zona reticularis.
CLINICAL FEATURES. The clinical features of secondary
adrenocortical insufficiency are like those of Addison’s Cortical Carcinoma
disease except the following:
1. These cases lack hyperpigmentation because of Carcinoma of the adrenal cortex is an uncommon tumour
suppressed production of melanocyte-stimulating hormone occurring mostly in adults. It invades locally as well as
(MSH) from the pituitary. spreads to distant sites. Most cortical carcinomas secrete one
2. Plasma ACTH levels are low-to-absent in secondary of the adrenocortical hormones excessively.
insufficiency but are elevated in Addison’s disease.
3. Aldosterone levels are normal due to stimulation by MORPHOLOGIC FEATURES. Grossly, an adrenal
renin. carcinoma is generally large, spherical and well-
demarcated tumour. On cut section, it is predominantly
HYPOALDOSTERONISM yellow with intermixed areas of haemorrhages, necrosis
and calcification. CHAPTER 27
Isolated deficiency of aldosterone with normal cortisol level Microscopically, the cortical carcinoma may vary from
may occur in association with reduced renin secretion. well-differentiated to anaplastic growth. Well-
ETIOPATHOGENESIS. The causes of such hyporeninism differentiated carcinoma consists of foci of atypia in an
are as follows: adenoma, while anaplastic carcinoma shows large,
1. Congenital defect due to deficiency of an enzyme required pleomorphic and bizarre cells with high mitotic activity.
for its synthesis.
2. Prolonged administration of heparin. MEDULLARY TUMOURS
3. Certain diseases of the brain. The most significant lesions of the adrenal medulla are
4. Excision of an aldosterone-secreting tumour.
neoplasms. These include the following: The Endocrine System
CLINICAL FEATURES. The patients of isolated hypo- Benign tumours: These are less common and include
aldosteronism are adults with mild renal failure and diabetes pheochromocytoma and myelolipoma.
mellitus. The predominant features are hyperkalaemia and Tumours arising from embryonic nerve cells: These are more
metabolic acidosis. common and include neuroblastoma and ganglioneuroma.
These tumours together with extra-adrenal paragang-
TUMOURS OF ADRENAL GLANDS lioma are described below.
Primary tumours of the adrenal glands are uncommon and
include distinct adrenocortical tumours and medullary Pheochromocytoma (Chromaffin Tumour)
tumours. However, adrenal gland is a more common site for Pheochromocytoma (meaning dusky brown tumour) is
metastatic carcinoma. generally a benign tumour arising from the pheochromocytes
(i.e. chromaffin cells) of the adrenal medulla. The extra-
ADRENOCORTICAL TUMOURS adrenal pheochromocytomas arising from other paraganglia
are preferably called paragangliomas, named along with the
Cortical Adenoma
anatomic site of origin, as described later.
The commonest cortical tumour is adenoma. They are Pheochromocytoma may occur at any age but most
indistinguishable from hyperplastic nodules except that patients are 20-60 years old. Most pheochromocytomas are
lesions smaller than 2 cm diameter are labelled hyperplastic slow-growing and benign but about 5% of the tumours are
nodules. A cortical adenoma is a benign and slow-growing malignant, invasive and metastasising. These tumours are
tumour. It is usually small and nonfunctional. A few large commonly sporadic but 10-20% are associated with familial
adenomas may, however, produce excess of cortisol, syndromes of multiple endocrine neoplasia (MEN) having
aldosterone or androgen. Association of cortical adenomas bilaterality and association with medullary carcinoma of the
with systemic hypertension has been suggested by some thyroid, hyperparathyroidism, pituitary adenoma, mucosal