Page 768 - Robbins Basic Pathology by Vinay Kumar, Abul K. Abbas, Jon C. Aster

754 C H A P T E R 19 Endocrine System
Figure 19–36 Diffuse hyperplasia of the adrenal (bottom) contrasted
with normal adrenal gland (top). In cross-section, the adrenal cortex is The signs and symptoms of Cushing syndrome represent
yellow and thickened, and a subtle nodularity is evident. The abnormal
gland was from a patient with ACTH-dependent Cushing syndrome, in
whom both adrenals were diffusely hyperplastic. ACTH, adrenocortico-
tropic hormone.
30 g. The adrenal cortex is diffusely thickened and variably
nodular, although the latter is not as pronounced as in cases
of ACTH-independent nodular hyperplasia. The yellow color
of diffusely hyperplastic glands derives from presence of
lipid-rich cells, which appear vacuolated under the
AB
Figure 19–37 Adrenocortical adenoma. A, The adenoma is distinguished from nodular hyperplasia by its solitary, circumscribed nature. The functional
status of an adrenocortical adenoma cannot be predicted from its gross or microscopic appearance. B, Histologic features of an adrenal cortical
adenoma. The neoplastic cells are vacuolated because of the presence of intracytoplasmic lipid. There is mild nuclear pleomorphism. Mitotic activity
and necrosis are not seen.
microscope. In primary cortical hyperplasia, the cortex is
replaced almost entirely by macro- or micronodules, with
the latter composed of 1- to 3-mm darkly pigmented nodules.
The pigment is believed to be lipofuscin, a wear-and-tear
pigment (Chapter 1).
Functional adenomas or carcinomas of the adrenal
cortex as the source of cortisol are not morphologically
distinct from nonfunctioning adrenal neoplasms (described
later). Both the benign and the malignant lesions are more
common in women in their 30s to 50s. Adrenocortical ade-
nomas are yellow tumors surrounded by thin or well-
developed capsules, and most weigh less than 30 g (Fig.
19–37, A). On microscopic examination, they are composed
of cells similar to those encountered in the normal zona
fasciculata (Fig. 19–37, B). The carcinomas associated with
Cushing syndrome, by contrast, tend to be larger than the
adenomas. These tumors are nonencapsulated masses fre-
quently exceeding 200 to 300 g in weight, having all of the
anaplastic characteristics of cancer, as detailed later on. With
functioning tumors, both benign and malignant, the adjacent
adrenal cortex and that of the contralateral adrenal gland are
atrophic, as a result of suppression of endogenous ACTH by
high cortisol levels.
Clinical Features
an exaggeration of the known actions of glucocorticoids.
Cushing syndrome usually develops gradually and, like
many other endocrine abnormalities, may be quite subtle
in its early stages. A major exception to this insidious onset
is with Cushing syndrome associated with small cell carci-
nomas of the lung, when the rapid course of the underlying
disease precludes development of many of the characteris-
tic features. Early manifestations of Cushing syndrome
include hypertension and weight gain. With time, the more
characteristic centripetal distribution of adipose tissue
becomes apparent, with resultant truncal obesity, “moon
facies,” and accumulation of fat in the posterior neck and