| tumor | 1. <oncology> An abnormal mass of tissue that results from excessive cell division that is uncontrolled and progressive, also called a neoplasm. Tumours perform no useful body function. They may be either benign (not cancerous) or malignant. 2. Swelling, one of the cardinal signs of inflammations, morbid enlargement. Origin: L. Tumere = to swell (12 May 1997) |
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| tumor marker | <investigation, oncology> A substance in the body that usually indicates the presence of cancer. These markers are usually specific to certain types of cancer and are usually found in the blood or other tissue samples. Examples are alphafetoprotein (AFP), human chorionic gonadotropin, and lactate dehydrogenase (LDH). They may be indicators of tumour stage and grade as well as useful for monitoring responses to treatment and predicting recurrence. Many chemical groups are represented including hormones, antigens, amino and nucleic acids, enzymes, polyamines, and specific cell membrane proteins and lipids. (18 Jul 2002) |
| tumor necrosis factor | <cytokine> Originally described as a tumour inhibiting factor in the blood of animals exposed to bacterial lipopolysaccharide or Bacille Calmette-Guerin. Preferentially kills tumour cells in vivo and in vitro, causes necrosis of certain transplanted tumours in mice and inhibits experimental metastases. Human Tumour Necrosis factor alpha is a protein of 157 amino acids and has a wide range of pro inflammatory actions. Usually considered a cytokine. Synonym: cachectin. Acronym: TNF (13 Nov 1997) |
| retroperitoneal | <anatomy> Behind or posterior to the peritoneum. (11 Jan 1998) |
| retroperitoneal adenopathy | <radiology> Ultrasound: increased echo most likely to be adenocarcinoma, decreased echo most likely to be lymphoma (12 Dec 1998) |
| retroperitoneal fibrosis | <radiology> Ureters tapered or obstructed, most severe at L4-5, ureters deviated medially, Treatment: symptomatic; steroids have ? long-term benefit Differential diagnosis: malignancy, lymphoma (especially Hodgkin's), metastasis from colon and breast, retroperitoneal sarcoma, drugs, methysergide (Sansert), haemorrhage, aortic aneurysm, trauma or surgery, inflammation, Crohn's disease, diverticulitis, pancreatitis, extravasated urine, radiation (12 Dec 1998) |
| retroperitoneal hernia | A hernia in the subperitoneal tissues. Synonym: retroperitoneal hernia, Treitz's hernia. (05 Mar 2000) |
| retroperitoneal liposarcoma | <radiology> Most common primary retroperitoneal tumour, rarely arises from lipoma, 95% of all fatty retroperitoneal tumours, 40-60 years; M>F, most radiosensitive sarcoma (32% 5-year survival) findings, CT, contrast enhancement, mixed density (fat and soft tissue elements), pseudocystic pattern: water density secondary to volume averaging, angio: hypovascular; no vessel dilation, capillary staining, laking sites for liposarcoma: lower extremity 45%, abdominal cavity and retroperitoneum 14%, trunk 14%, upper extremity 8%, head and neck 7% (12 Dec 1998) |
| retroperitoneal space | An area occupying the most posterior aspect of the abdominal cavity. It is bounded laterally by the borders of the quadratus lumborum muscles and extends from the diaphragm to the brim of the true pelvis, where it continues as the pelvic extraperitoneal space. (12 Dec 1998) |