Secretory cells in
Adrenal cortical cells, adrenal cortex.
11,500; inset (
Cells of the
have features common to all cells that synthesize and secrete steroid hormones. The three most prominent
components of the cytoplasm are an abundance of
smooth endoplasmic reticulum
that have peculiar
lipid droplets. Cholesterol
, the precursor of steroid hormones, is stored as esters in the lipid droplets. Enzymes necessary for
synthesis of steroid hormones are located in the SER and in the inner mitochondrial membrane, so hormone production is a cooperative
function of these two organelles. Although proteins are not secreted by these cells, protein synthesis is required to maintain structure
and function. This is reﬂ ected by the prominent nucleolus and by the patches of RER.
of the adrenal medulla
characterized by the production of
, such as
, which cause signiF
tension, often episodic, in affected patients. Most pheochro-
mocytomas are sporadic, but about 10% are associated with
familial syndromes such as
. Some pheochromocytomas are bilateral, and
although most occur in adults, about 10% occur in children.
Grossly, most of these tumors are well circumscribed and
range in size from a few grams to kilograms. Microscopically,
pheochromocytomas can have a diverse appearance, from
spindle cells to large, bizarre cells. The cells are often arranged
in nests, or cell packets called
. Histologic features
alone do not reliably separate benign tumors from malignant
ones; therefore, the demonstration of metastases is necessary to
ascertain malignancy. DeF
nitive treatment is surgical removal
of the tumor.