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Tumors and
Malformations of Vessels |
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Developmental malformations derived from blood
vessels are very common and are termed
angiomas or haemangiomas.
• Haemangiomas are composed of dilated vascular spaces.
• Capillary angiomas are composed of small capillary-like vessels.
• Cavernous angiomas are composed of wide, vein-like vessels.
• Angiomas with mixed patterns are common.
Vascular tissues (usually abnormal) are an important, often predominant,
component
of mixed connective tissue hamartomatous malformations in the subcutaneous
tissue
of the neck and upper trunk in young people.
In some cases lymphatic vessels are the predominant feature, and in children
such
malformations may consist almost entirely of enormously dilated lymphatic
vessels
(cystic hygroma).} Other connective tissues present include adipose tissue,
abnormal
nerves, and some smooth muscle.
Cavernous angioma is composed of vein-like vascular spaces filled with blood.
True tumours of blood vessels are rare, but include Kaposi's sarcoma, which is
becoming a more important and common tumour.
Numerically the most common tumour is the so-called glomus tumour (glomangioma),
which presents as a tender, painful nodule on the finger, often close to the
nail.
The tumour contains vascular channels surrounded by glomus cells.
Angiosarcoma
a malignant tumour of blood vessel endothelium, most commonly occurs as a raised
bluish
red patch on the face or scalp of elderly people. It enlarges progressively,
often
ulcerating, and later metastasizes to regional lymph nodes. This tumour may also
occur in
limbs that have very long-standing chronic lymphoedema but this is now very
rare, and
was most commonly seen in the arms of women who had had a total axillary
clearance as
part of radical surgery for breast cancer.
Angiosarcomas in the liver have been associated with industrial exposure to
vinyl chloride,
which is used in various chemical industries (particularly plastic
manufacturing).
Haemangioendotheliomas behave as low-grade malignant tumours and are derived
from endothelial cells.
Haemangiopericytomas, also of low-grade malignant potential, are derived from
the
pericytes surrounding blood vessels. Occurring mainly in the subcutaneous
tissues of the
limbs, they occasionally develop in other sites.
An angiosarcoma is composed of neoplastic endothelial cells, which form
vascular-like
channels in tissues. This is a highly malignant tumour.
One form of Kaposi's sarcoma is seen with AIDS
Kaposi's sarcoma is believed to be derived from endothelial cells. However,
evidence for this
is controversial and there have been proposals that the tumour arises from
multipotential
mesenchymal cells. There are four patterns of disease, the natural histories of
which seem to
be related to the clinical setting in which the tumour develops. Only one form
is seen in AIDS.
Endemic Kaposi's sarcoma is seen in Africa.
In children it is a highly malignant condition based in lymph nodes, but in
adults it runs a more
indolent course, with haematogenous spread.
Classic Kaposi's sarcoma is a rare tumour that develops in the lower limbs of
elderly males.
It behaves as a low-grade malignant skin neoplasm, with haematogenous and lymph
node metastasis.
Kaposi's sarcoma in therapeutic immunosuppression resembles classic Kaposi's
sarcoma, behaving as
a low-grade malignant neoplasm in the skin.
Epidemic Kaposi's sarcoma is seen in patients with AIDS, particularly in
homosexual males.
It is a highly malignant tumour of skin with spread to lymph nodes and visceral
organs. |
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We give here simplified and accurate information about the disease
Info@somalidoc.com |
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