tumor - an abnormal new mass of tissue that serves no purposegrowth - (pathology) an abnormal proliferation of tissue (as in a tumor) angioma - a tumor consisting of a mass of blood or lymphatic vessels carcinoid - a small tumor (benign or malignant) arising from the mucosa of the gastrointestinal tract; usually associated with excessive secretion of serotonin granuloma - a tumor composed of granulation tissue resulting from injury or inflammation or infection meningioma - a tumor arising in the meninges which surround the brain and spinal cord; usually slow growing and sometimes malignant neuroma - any tumor derived from cells of the nervous system plasmacytoma - neoplasm of plasma cells (usually in bone marrow) psammoma, sand tumor - a tumor derived from fibrous tissue of the meninges or choroid plexus or certain other structures associated with the brain; characterized by sand-like particles teratoma - a tumor consisting of a mixture of tissues not normally found at that site |