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Angiosarcomas are rare malignant mesenchymal tumours, characterized
morphologically by anastomosing vascular channels lined by atypical
and proliferative active endothelial cells .
The tumour may
vary from highly differentiated tumours that resemble hemangiomas to
poorly differentiated anaplastic lesions that may be difficult to
distinguish from carcinomas or melanomas.
Angiosarcoma has a high rate of metastasis involving lungs (most
commonly), liver, regional lymph nodes, bone, and other sites.
Site:
Angiosarcomas have a predilection for skin
and superficial soft tissue (Note: Most soft tissue sarcomas are deep seated ). The sites include skin (with or without lymphedema),
soft tissue, breast, liver, bone, spleen, heart and great vessels,
orbit, pharynx, oral cavity, salivary gland, gastrointestinal tract,
larynx, nasal cavity, kidney, prostate etc.
Clinicopathological types:
1. Idiopathic
angiosarcoma of the face, neck and scalp ; 2. Lymphedema associated
angiosarcoma ; 3. Post-irradiation angiosarcoma ; 4. Soft
tissue angiosarcoma ; 5. Angiosarcoma of the breast.
Cutaneous angiosarcoma is the
most common form of angiosarcoma:
Age:
Usually in elderly patients (higher incidence in male).
Site:
Head and neck particularly scalp and upper forehead.
Clinical
presentation:
Multifocal
bruise-like areas with indurated border. Large advanced lesions are
elevated, nodular and occasionally ulcerated. Grossly, the tumour extensively involves the dermis . Poorly-differentiated
lesions may invade the deep structures such as subcutis and
fascia.
Prognosis is poor.
Death is due to extensive local disease or wide spread metastasis
(mainly to the lungs).
Prognostic factors:
External diameter of the tumour (>5 cm), depth of invasion (>3 mm),
mitotic rate (>3 HPF), positive surgical margins, tumour recurrence,
and metastases correlated with adverse outcome.
Chronic lymphadenoma is the
most widely recognized predisposing factor in angiosarcoma of skin and
soft tissue:
Lymphedema
associated angiosarcomas occur in woman who have undergone
radical mastectomy with removal of axillary lymphnode for breast
carcinoma and have suffered from chronic severe lymphedema for many
years. (Stewart Treves Syndrome) .
Site:
Arms in patients with lymphedema following mastectomy ; Abdominal wall
following lymph node dissection for carcinoma of penis ; Arms
and legs of patients with congenital lymphedema, iatrogenic lymphedema
, lymphatic malformation and filarial lymphedema.
Age:
Elderly patients (seventh
decade) in cases of lymphedema following mastectomy. Affected
patients are younger (fourth or fifth decade) in cases of congenital
or idiopathic lymphedema.
Clinical presentation:
Bluish plaque, nodules and vesicles.
Post irradiation angiosarcoma presents many
years after radiation therapy for benign or malignant conditions:
Post irradiation
angiosarcomas have occurred following radiotherapy for another
malignancy such as carcinoma of the breast, cervix, ovary, endometrium
and Hodgkin's disease.
Cutaneous postradiation angiosarcoma of the breast
(CPRASB) may occur in patients who have undergone breast-conserving
therapy combined with adjuvant radiation.
CPRASB differs from
Stewart-Treves angiosarcoma by its shorter latency period and lack of
association with lymphedema.
Site:
Chest wall, abdomen, shoulder, groin, flank, axilla and lower leg.
Clinical
presentation: The characteristic purple
nodules and discoloration of the irradiated skin is the hallmark to
suspect the diagnosis. Presentation
ranges from small erythematous/violaceous papules or nodules to large
plaques.
Prognosis is poor
like other types of angiosarcoma.
Soft Tissue Angiosarcomas :
Age:
The tumour may occur at any age. These are mostly common in elderly
patients.
Site:
Extremities or abdominal cavity (including retroperitoneum).
Clinical
presentation: Presents
as large
hemorrhagic mass.
In most cases the
tumour shows epithelioid cytomorphology.
Miscellaneous angiosarcomas:
Rare cases of angiosarcoma have been reported
to arise in the setting of retained foreign material such a shrapnel,
surgical sponges and adjacent to a Dacron vascular prosthesis.
Angiosarcomas have
occured in pre-existing benign vascular tumours including lymphangioma,
'port wine' stains and in benign and malignant peripheral nerve sheath tumours.
Angiosarcomas have been
reported as a complication of renal transplantation, arteriovenous
fistulae, varicose ulceration, xeroderma pigmentosum and gouty tophus.
There is relatively
strong evidence linking various substances to the induction of hepatic
angiosarcoma. About one fourth of hepatic angiosarcoma occur in
patients who have received thorium dioxide (Thorotrast) for cerebral
angiography, in vineyard workers exposed to AsO3-containing insectides, or
in industrial workers exposed to vinyl chloride used in the production of
synthetic rubber.
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