| angioma | <dermatology, oncology> A knot of distended blood vessels atypically and irregularly arranged. most are not tumours but haematomas. (06 Mar 1998) |
|---|---|
| angioma lymphaticum | <oncology, tumour> A localised collection of lymphatic vessels resulting in a nodule or mass. most are congenital. (27 Sep 1997) |
| capillary angioma | <dermatology> Red or purple-coloured vascular skin markings that develop shortly after birth. Most are usually painless and benign and sharply demarcated from surrounding skin, usually located on the head and neck, and grow rapidly. It is caused by proliferation of immature capillary vessels in active stroma, and is usually present at birth or occurs within the first two or three months of life. Some lesions (cavernous haemangioma) will disappear or become harder to see as the child approaches school age. Localised steroid injections have been used successfully to reduce the size of a birthmark but generally they undergo spontaneous regression and involution without scarring and normally require no treatment. (07 Mar 2000) |
| venous angioma | <radiology> Caput medusae, wedge-shaped appearance with its base at the meninges and its apex directed toward the ventricles, prominent medullary vein drains into a markedly enlarged transcortical cerebral vein, angiogram: normal arterial phase without AV shunting (12 Dec 1998) |
| cavernous angioma | Vascular malformation composed of sinusoidal vessels without a large feeding artery; can be multiple, especially if inherited as an autosomal dominant trait. Synonym: nevus cavernosus. (05 Mar 2000) |
| cherry angioma | <oncology, tumour> A benign and common skin growth which is characterised by smooth, bright red growth that may be a millimetre to one quater inch across. Diagnosis is made by appearance of the lesion. More commonly seen on the trunk in individuals over 40 years of age. No treatment is necessary, although cosmetic removal via cryotherapy may be an option. (27 Sep 1997) |
| superficial angioma | <dermatology> Red or purple-coloured vascular skin markings that develop shortly after birth. Most are usually painless and benign and sharply demarcated from surrounding skin, usually located on the head and neck, and grow rapidly. It is caused by proliferation of immature capillary vessels in active stroma, and is usually present at birth or occurs within the first two or three months of life. Some lesions (cavernous haemangioma) will disappear or become harder to see as the child approaches school age. Localised steroid injections have been used successfully to reduce the size of a birthmark but generally they undergo spontaneous regression and involution without scarring and normally require no treatment. (07 Mar 2000) |
| telangiectatic angioma | <tumour> Angioma composed of dilated vessels. Angioma venosum racemosum, tortuous swelling caused by varicosities of superficial veins. Venous angioma, vascular anomaly composed of anomalous veins. (05 Mar 2000) |
| arteriovenous | <anatomy> Both arterial and venous, pertaining to or affecting an artery and a vein. (18 Nov 1997) |
| arteriovenous anastomosis | <anatomy> A vessel that directly interconnects an artery and a vein, and that acts as a shunt to bypass the capillary bed. Not to be confused with surgical anastomosis, nor with arteriovenous fistula. (12 Dec 1998) |
| arteriovenous aneurysm | <anatomy> A dilated arteriovenous shunt where there is communication between an artery and a vein, sometimes congenital. (05 Mar 2000) |
| arteriovenous carbon dioxide difference | <physiology> The difference in carbon dioxide content (in ml per 100 ml blood) between arterial and venous blood. (05 Mar 2000) |
| arteriovenous fistula | <surgery> The surgical joining of an artery and a vein under the skin for the purpose of haemodialysis. Larger arteriovenous shunts can place strain on the heart since arterial blood is diverted back to the venous circulation before it has a chance to deliver nutrients and oxygen to the body tissues. (27 Sep 1997) |
| arteriovenous malformation | <anatomy, embryology> A tangled collection of abnormal blood vessels where there is an abnormal communication between the arterial and venous systems. The afferents flow directly into the venous efferents without the usual resistance of an intervening capillary bed. They are mostly congenital. If large enough, they may produce a shunt of sufficient magnitude to raise the cardiac output. Common sites include; skin, liver, brain, brainstem and spinal cord, where they may cause headaches, seizures or bleeding (subarachnoid haemorrhage). See: arteriovenous fistula, cerebral arteriovenous malformations. Synonym: haemangioma (20 Jun 2000) |
| arteriovenous oxygen difference | <physiology> The difference in the oxygen content (in ml per 100 ml blood) between arterial and venous blood. (05 Mar 2000) |