Page 408 - Textbook of Pathology, 6th Edition

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Figure 15.2 Diagrammatic representation of three forms of arteriolosclerosis, commonly seen in hypertension.

PATHOGENESIS. The pathogenesis of hyperplastic intimal MORPHOLOGIC FEATURES. Medial calcification is
thickening is unclear. Probably, the changes result following often an incidental finding in X-rays of the affected sites
endothelial injury from systemic hypertension, hypoxia or having muscular arteries. The deposition of calcium salts
immunologic damage leading to increased permeability. A in the media produces pipestem-like rigid tubes without
healing reaction occurs in the form of proliferation of smooth causing narrowing of the lumen.
muscle cells with fibrosis.
Microscopically, Mönckeberg’s arteriosclerosis is
characterised by deposits of calcium salts in the media
Necrotising Arteriolitis without associated inflammatory reaction while the intima
SECTION III
and the adventitia are spared (Fig. 15.3). Often, coexistent
In cases of severe hypertension and malignant hypertension, changes of atherosclerosis are present altering the
parts of small arteries and arterioles show changes of hyaline histologic appearance.
sclerosis and parts of these show necrosis, or necrosis may
be superimposed on hyaline sclerosis. However, hyaline PATHOGENESIS. Pathogenesis of this condition is not
sclerosis may not be always present in the vessel wall. known but it is considered as an age-related physiologic
change due to prolonged effect of vasoconstriction.
MORPHOLOGIC FEATURES. Besides the changes of
hyaline sclerosis, the changes of necrotising arteriolitis
include fibrinoid necrosis of vessel wall, acute
inflammatory infiltrate of neutrophils in the adventitia.
Oedema and haemorrhages often surround the affected
Systemic Pathology
vessels (Fig. 15.2,C).
PATHOGENESIS. Since necrotising arteriolitis occurs in
vessels in which there is sudden and great elevation of
pressure, the changes are said to result from direct physical
injury to the vessel wall.

MÖNCKEBERG’S ARTERIOSCLEROSIS
(MEDIAL CALCIFIC SCLEROSIS)
Mönckeberg’s arteriosclerosis is calcification of the media of
large and medium-sized muscular arteries, especially of the
extremities and of the genital tract, in persons past the age
of 50. The condition occurs as an age-related degenerative
process, and therefore, an example of dystrophic calcification,
and has little or no clinical significance. However, medial
calcification also occurs in some pathological states like Figure 15.3 Monckeberg’s arteriosclerosis (medial calcific sclerosis).
pseudoxanthoma elasticum and in idiopathic arterial There is calcification exclusively in the tunica media unassociated with
calcification of infancy. any significant inflammation.