| haemangioendothelioma, epithelioid | A tumour of medium-to-large veins, composed of plump-to-spindled endothelial cells that bulge into vascular spaces in a tombstone-like fashion. These tumours are thought to have "borderline" aggression, where one-third develop local recurrences, but only rarely metastasize. It is unclear whether the epithelioid haemangioendothelioma is truly neoplastic or an exuberant tissue reaction, nor is it clear if this is equivalent to kimura's disease (see angiolymphoid hyperplasia with eosinophilia). (12 Dec 1998) |
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| haemangiofibroma | A haemangioma with an abundant fibrous tissue framework. (05 Mar 2000) |
| haemangioma | <cardiology, dermatology, embryology, physiology> A haemangioma or arteriovenous malformation is a tangle of abnormal vessels that forms an abnormal communication between the arterial and venous systems. most are congenital and result from improperly formed angioblastic tissue in the foetus. If large enough, they may produce a shunt of sufficient magnitude to raise the cardiac output. Arteriovenous malformations may occur in the brain, brainstem and spinal cord, where they may cause headaches, seizures or bleeding (subarachnoid haemorrhage). Red or purple-coloured vascular skin markings that develop shortly after birth. most are usually painless and benign. Some lesions (cavernous haemangiomas) 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. (18 Nov 1997) |
| haemangioma of bone | <radiology> Lytic bone lesion, can cross joint spaces and interosseous membranes Findings: vertebral body: vertical striations (ivory), skull: sunburst or sunrise, long bone: soap bubble or honeycomb, which may surround a joint see also: Mafucci syndrome (12 Dec 1998) |
| haemangioma of vertebrae | <radiology> Cavernous type commonly found, 10% in autopsy series with the vast majority being small, asymptomatic and unable to be seen on plain films, most often in lumbar region and singular, complications: compression fractures (occasionally with cord compression), chronic haemorrhage to blockage of spinal canal X-ray: slight loss of density of vertebral body, vertically striped orientation of bone trabeculae (corduroy cloth) which may extend into the pedicle, occasionally with posterior bulging, cortical margins usually intact see also: haemangioma of bone (12 Dec 1998) |
| haemangioma planum extensum | A benign, flat, cutaneous haemangioma of considerable size. (05 Mar 2000) |
| haemangioma, cavernous | A vascular tumour preponderantly composed of large dilated blood vessels, often containing large amounts of blood, occurring in the skin, subcutaneously, or both, and also in many viscera, particularly the liver, spleen, pancreas, and sometimes the brain. The typical superficial lesions are bright to dark red in colour; deep lesions have a blue colour. A cavernous haemangioma in the skin extends more deeply than a capillary haemangioma and is less likely to regress spontaneously. (12 Dec 1998) |
| haemangioma-thrombocytopenia syndrome | <syndrome> Thrombocytopenia caused by sequestration and destruction of platelets in a large cavernous haemangioma, usually seen in infants, rare in adults (12 Dec 1998) |
| haemangiomatosis | A condition in which there are numerous haemangiomas. (05 Mar 2000) |
| haemangiopericytoma | <oncology, tumour> A type of tumour thought to be formed from connective tissue cells and originating from capillaries. (09 Oct 1997) |
| haemangiosarcoma | A rare malignant neoplasm characterised by rapidly proliferating, extensively infiltrating, anaplastic cells derived from blood vessels and lining irregular blood-filled or lumpy spaces. (12 Dec 1998) |
| haemaphaein | <physiology> A brownish substance sometimes found in the blood, in cases of jaundice. Origin: Haema- + Gr. Dusky. Source: Websters Dictionary (01 Mar 1998) |
| haemapheic | Pertaining to or containing haemaphein. (05 Mar 2000) |
| haemaphein | A brown pathologic pigment derived from haemoglobin; said to be a combination of indican and urobilin. Origin: G. Haima, blood, + phaios, dusky (05 Mar 2000) |
| haemapheism | The presence of haemaphein in the blood plasma and urine. (05 Mar 2000) |