(Acroangiodermatitis
of Mali / Stewart-Bluefarb syndrome )
Acro-angiodermatitis is a
benign vascular process which histologically closely
resembles Kaposi's sarcoma and had thus been named "pseudo-Kaposi's
sarcoma.
Acro-angiodermatitis is
often associated with different disorders like: chronic venous
insufficiency, arterio-venous malformations, arterio-venous shunts,
acquired arteriovenous fistula, paralysed limb,
Klippel-Trenaunay-Weber syndrome. It has also been reported above
knee amputation stump.
Site:
Lower part of the legs and on the feet.
Clinical presentation: The
lesion presents as circumscribed violaceous, brown or dusky macules,
papules, plaques and nodules.
Microscopic features:
Image Link
;
Image Link
Proliferation of small dilated vessels in a thickened edematous papillary dermis
and sometimes in the upper reticular dermis.
The vessels have a
regular profile . Some lesions show nodular collection of blood vessels
with perivascular inflammation.
The small vessels are
thick walled and are lined plump endothelial cells . There are no atypical
features.
There is some
perivascular fibroblastic proliferation with variable fibroplasia.
Other features : Hyperkeratosis of overlying epidermis ; extravasated
red blood cells , hemosiderin and variable infiltrate of lymphocytes around
vascular proliferation.
Differential diagnosis:
Kaposi's Sarcoma -
Thin-walled
vessels aligned along normal venules ; jagged outline ; thin oval
endothelial cells distributed interstitially in the reticular dermis; an
infiltrate of plasma cells around pre-existing venules ;
In
contrast to true Kaposi's sarcoma, in acroangiodermatitis
human-herpes-virus-8 DNA can not be detected by polymerase-chain-reaction;
Kaposi's sarcoma showed CD34 positive staining of endothelial cells and on
the characteristic spindle-shaped , perivascular cells. Biopsies of
pseudo-Kaposi's sarcoma showed a strong CD34 positive staining of
endothelial cells of hyperplastic vessels. However, in sharp contrast with
Kaposi's sarcoma, a complete absence of perivascular CD34 expression was
noted.
Stasis dermatitis
- ( unlike stasis
dermatitis, acroangiodermatitis is usually associated with
minimal epidermal changes and eosinophils in the inflammatory infiltrate
in the dermis ) ;
Pigmented purpura ;
vasculitis.
|
