10
UNIT 1
Basic Principles of Cell Structure and Function
Anthracosis.
H&E,
3
155
Anthracosis
is an exogenous pigment composed of carbona-
ceous material from smoking and air pollution. Inhaled carbon
is taken up by alveolar macrophages and transported to lymph
nodes. Anthracotic tissues are black in gross appearance.
Image:
This lymph node from the hilar region of the lung shows
abundant macrophages containing black carbonaceous material.
Melanin.
H&E,
3
388
Melanin pigment
, a product of melanocytes, can normally be
seen in the basal
keratinocytes of the skin. In some chronic
infl
ammatory skin conditions, melanin is released into the der-
mis and taken up by dermal macrophages, or
melanophages
.
Image:
Black-brown melanin pigment is present within the pap-
illary dermal
macrophages.
Lipofuscin.
H&E,
3
388
Also known as
lipochrome
,
lipofuscin
is a yellow-brown pigment
related to tissue aging. Lipofuscin is insoluble and composed of
phospholipids and lipids as a result of lipid peroxidation. It is
commonly seen in the liver and heart.
Image:
This hypertrophic cardiac myocyte from an older indi-
vidual contains lipofuscin granules adjacent to the nucleus.
Hemosiderin.
H&E,
3
155 (left); Prussian blue,
3
155 (right)
Hemosiderin
is the tissue storage form of iron, which appears as
granular, coarse, golden-brown pigment. Hemosiderin is formed
from the breakdown of red blood cells and is taken up into tissue
macrophages. It may be seen in tissues in which remote bleeding
has occurred or in any condition in which excess iron is present.
Images:
The F
rst image (
left
) shows abundant hemosiderin-laden
macrophages in soft tissue where past bleeding has occurred.
The second image (
right
) is a Prussian blue preparation of the
same tissue, showing the deep blue staining of hemosiderin.
Pigments
Pigments
are colored substances found within tissue mac-
rophages or parenchymal cells. Pigments may be
endogenous
,
those
produced by the body, or
exogenous
, those originating
outside of the body.
Melanin
,
lipofuscin
, and
hemosiderin
are
the most
common
endogenous
pigments. The most common
exogenous
pigment is
carbon
.
Ulcer.
H&E,
3
25
An
ulcer
represents the discontinuity of an epithelial surface, which
may involve skin or mucous membranes. Ulcers may be caused by
infectious processes, chemical exposures, prolonged pressure, or vas-
cular compromise. They typically form crater-shaped lesions with
a superF cial F brinopurulent layer and an underlying vascular and
F
broblastic proliferation called
granulation tissue
.
Image:
This is an image of a gastric ulcer. Note the intact mucosa
transitioning to the ulcer with a F
brinopurulent surface. The for-
mation of gastric ulcers is closely associated with infection with
H. pylori
. Gastric ulcers may be benign or malignant, representing
gastric adenocarcinoma.
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