Hemangioendothelioma: A neoplasm derived from blood vessels, characterized by numerous prominent endothelial cells that occur singly, in aggregates, and as the lining of congeries of vascular tubes or channels. Hemangioendotheliomas are relatively rare and are of intermediate malignancy (between benign hemangiomas and conventional angiosarcomas). They affect men and women about equally and rarely develop in childhood. (From Stedman, 25th ed; Holland et al., Cancer Medicine, 3d ed, p1866)Hemangioendothelioma, Epithelioid: A tumor of medium-to-large veins, composed of plump-to-spindled endothelial cells that bulge into vascular spaces in a tombstone-like fashion. These tumors are thought to have "borderline" aggression, where one-third develop local recurrences, but only rarely metastasize. It is unclear whether the epithelioid hemangioendothelioma 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). (Segen, Dictionary of Modern Medicine, 1992)Kasabach-Merritt Syndrome: Rapidly growing vascular lesion along the midline axis of the neck, upper trunk, and extremities that is characterized by CONSUMPTION COAGULOPATHY; THROMBOCYTOPENIA; and HEMOLYTIC ANEMIA. It is often associated with infantile Kaposiform HEMANGIOENDOTHELIOMA and other vascular tumors such as tufted ANGIOMA.Hemangiosarcoma: A rare malignant neoplasm characterized by rapidly proliferating, extensively infiltrating, anaplastic cells derived from blood vessels and lining irregular blood-filled or lumpy spaces. (Stedman, 25th ed)Neoplasms, Vascular Tissue: Neoplasms composed of vascular tissue. This concept does not refer to neoplasms located in blood vessels.Vascular Neoplasms: Neoplasms located in the vasculature system, such as ARTERIES and VEINS. They are differentiated from neoplasms of vascular tissue (NEOPLASMS, VASCULAR TISSUE), such as ANGIOFIBROMA or HEMANGIOMA.Hemangioma: A vascular anomaly due to proliferation of BLOOD VESSELS that forms a tumor-like mass. The common types involve CAPILLARIES and VEINS. It can occur anywhere in the body but is most frequently noticed in the SKIN and SUBCUTANEOUS TISSUE. (from Stedman, 27th ed, 2000)Bones of Lower Extremity: The bones of the upper and lower LEG. They include the PELVIC BONES.Endothelium, Lymphatic: Unbroken cellular lining (intima) of the lymph vessels (e.g., the high endothelial lymphatic venules). It is more permeable than vascular endothelium, lacking selective absorption and functioning mainly to remove plasma proteins that have filtered through the capillaries into the tissue spaces.Labyrinth Diseases: Pathological processes of the inner ear (LABYRINTH) which contains the essential apparatus of hearing (COCHLEA) and balance (SEMICIRCULAR CANALS).Ear Neoplasms: Tumors or cancer of any part of the hearing and equilibrium system of the body (the EXTERNAL EAR, the MIDDLE EAR, and the INNER EAR).Sarcoma, Kaposi: A multicentric, malignant neoplastic vascular proliferation characterized by the development of bluish-red cutaneous nodules, usually on the lower extremities, most often on the toes or feet, and slowly increasing in size and number and spreading to more proximal areas. The tumors have endothelium-lined channels and vascular spaces admixed with variably sized aggregates of spindle-shaped cells, and often remain confined to the skin and subcutaneous tissue, but widespread visceral involvement may occur. Kaposi's sarcoma occurs spontaneously in Jewish and Italian males in Europe and the United States. An aggressive variant in young children is endemic in some areas of Africa. A third form occurs in about 0.04% of kidney transplant patients. There is also a high incidence in AIDS patients. (From Dorland, 27th ed & Holland et al., Cancer Medicine, 3d ed, pp2105-7) HHV-8 is the suspected cause.Blue Toe Syndrome: A condition that is caused by recurring atheroembolism in the lower extremities. It is characterized by cyanotic discoloration of the toes, usually the first, fourth, and fifth toes. Discoloration may extend to the lateral aspect of the foot. Despite the gangrene-like appearance, blue toes may respond to conservative therapy without amputation.Liver Neoplasms: Tumors or cancer of the LIVER.Spinal NeoplasmsFatal Outcome: Death resulting from the presence of a disease in an individual, as shown by a single case report or a limited number of patients. This should be differentiated from DEATH, the physiological cessation of life and from MORTALITY, an epidemiological or statistical concept.Thoracic Vertebrae: A group of twelve VERTEBRAE connected to the ribs that support the upper trunk region.