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Background Histopathology & Immunohistochemistry
BACKGROUND AND CLINICAL INFORMATION:
Head
Age:
adults (40-50 y/o).
Prognosis:
with immunosuppressive therapy, the survival is about 55-75%.
Systemic
PAN:
the visceral organs (heart, kidneys, and GI tract) except the lung and spleen.
PNS is involved in 50% of cases.
Limited
PAN:
neurological
manifestations frequently occur. Muscle and peripheral nerves are also
frequently affected.
HISTOPATHOLOGY AND IMMUNOHISTOCHEMISTRY:
Head
Size
of arteries affected: This
is principlally a disease of the media. Medium
size muscular arteries
and small arteries,
may spread into the arteries. PAN affects renal, and visceral vessels, sparing
the pulmonary circulation.
Veins
and capillaries
are usually spared.
Size
of lesions: Most
lesions are not more than 1 mm in length and vasculitis does not necessarily
affect the whole circumference. May be acute, subacute, or chronic, frequently
remittent.
Stages:
Acute
stage: fibrinoid
necrosis, from intima to adventitia, inflammation, bulging, perivascular
cuff of cells. Aneurysm may be seen during the acute stage. Thrombosis
occurs in the acute stage and there may be destruction of the elastica,
especially internal elastic membrane.
Healing
stage:
fibroblstic proliferation, concentric arrangement of fibroblasts in the
intima, macrophages or plasma cell infiltration with firm nodularity.
Healed
stage: marked
fibrotic thickening, lymphocytes, plasma cells. firbotic replacement of
elastic tissue, calcification.
NeuroLearn NeuroHelp Vascular For Comment: KarMing-Fung@ouhsc.edu