, also called
, is a degenera-
tive skin condition, which mainly affects the
of the sun-exposed areas of the body. Frequent
exposure of the skin to sunlight or ultraviolet light causes
and accelerates this degenerative process. Actinic keratosis
is a premalignant lesion. Signs and symptoms include loose,
wrinkled, dry, and sagging skin. Histologically, the amount
present in the affected skin is decreased,
whereas the amount of
increases, but they lose
some of their elasticity and ﬂ
exibility. A bluish discoloration
of the papillary dermis is characteristic of ultraviolet dam-
age to the connective tissue of the dermis.
loose collagen f
are illustrated here. Avoiding
unnecessary sun exposure is the most important prevention.
Treatment includes liquid
nitrogen cryotherapy, surgical
curettage, and chemotherapy.
Dense irregular connective tissue, mammary
Dense irregular connective tissue
can be found in the
and also in other places such as capsules of organs. In
this example, dense irregular connective tissue in the mammary
gland is shown, distributed in between glandular tissues.
gen f bers
predominate, appear pink, and are arranged in wavy
bundles without a consistent orientation.
among these ±
and glands can
be found in dense irregular connective tissue; however, dense
irregular connective tissue is generally not a richly vascularized
Dense irregular connective tissue, dermis o±
Collagen f bers
are arranged in randomly oriented bundles and
appear pink here; they are the principal ± bers in
. Collagen ±
bers are ﬂ
exible and have a high ten-
Elastic f bers
are made visible with a special stain
and are seen as thin, dark strands scattered among the collagen
± bers. They have the ability to stretch and return to their origi-
nal length. Dense irregular connective tissue is a cushionlike
tissue, which provides great strength against
on structures or organs.