| leishmaniasis, cutaneous | An endemic disease that is characterised by the development of single or multiple localised lesions on exposed areas of skin that typically ulcerate. The disease has been divided into old and new world forms. Old world leishmaniasis is separated into three distinct types according to epidemiology and clinical manifestations and is caused by species of the l. Tropica and l. Aethiopica complexes as well as by species of the l. Major genus. New world leishmaniasis, also called american leishmaniasis, occurs in south and central america and is caused by species of the l. Mexicana or l. Braziliensis complexes. (12 Dec 1998) |
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| leishmaniasis, diffuse cutaneous | A form of leishmaniasis, cutaneous caused by leishmania aethiopica in ethiopia and kenya, l. Pifanoi in venezuela, l. Braziliensis in south america, and l. Mexicana in central america. This disease is characterised by massive dissemination of skin lesions without visceral involvement. (12 Dec 1998) |
| lesser internal cutaneous nerve | <anatomy, nerve> Arises from the medial cord of the brachial plexus, unites in the axilla with the lateral cutaneous branch of the second intercostal nerve, and supplies the skin of the medial side of the arm. Synonym: nervus cutaneus brachii medialis, lesser internal cutaneous nerve, medial cutaneous nerve of arm, Wrisberg's nerve. (05 Mar 2000) |
| lower lateral cutaneous nerve of arm | <anatomy, nerve> A branch of the radial nerve supplying the skin of the lower lateral aspect of the arm; it frequently is a branch of the posterior antebrachial nerve. Synonym: nervus cutaneus brachii lateralis inferior, lower lateral cutaneous nerve of arm. (05 Mar 2000) |
| lupus erythematosus, cutaneous | A form of lupus erythematosus in which the skin may be the only organ involved or in which skin involvement precedes the spread into other body systems. It has been classified into three forms - acute (= lupus erythematosus, systemic with skin lesions), subacute, and chronic (= lupus erythematosus, discoid). (12 Dec 1998) |
| lymphoma, T-cell, cutaneous | A group of lymphomas exhibiting clonal expansion of malignant T-lymphocytes arrested at varying stages of differentiation as well as malignant infiltration of the skin. Mycosis fungoides and sezary syndrome are the best characterised of these disorders. (12 Dec 1998) |
| adrenal cyst | <radiology> Same characteristics as renal cysts, but less common, thick wall, septations, calcifications suggests pseudocyst (12 Dec 1998) |
| adventitious cyst | 1. An accumulation of fluid in a cystlike loculus, but without an epithelial or other membranous lining. Synonym: adventitious cyst, false cyst. 2. A cyst whose wall is formed by a host cell and not by a parasite. 3. A mass of 50 or more Toxoplasma bradyzoites, found within a host cell, frequently in the brain; formerly called a pseudocyst, but now considered a true cyst enclosed in its own membrane within the host cell that may rupture to release particles that form new cysts, and apparently is infective to another vertebrate host. See: bradyzoite. Origin: pseudo-+ G. Kystis, bladder (05 Mar 2000) |
| allantoic cyst | Cyst occurring in a persistent portion of the urachus, presenting as an extraperitoneal mass in the umbilical region. It is characterised by abdominal pain, and fever if infected. It may rupture, leading to peritonitis, or it may drain through the umbilicus. (12 Dec 1998) |
| alveolar hydatid cyst | A hydatid cyst of a multiloculate type, usually in the liver, caused by Echinococcus multilocularis, adults of which are in foxes; larvae (alveolar hydatid) are found chiefly in microtine rodents, but also among humans such as trappers and others handling pelts of infected foxes and other carnivores; growth is by exogenous budding and is not limited by an outer laminated membrane as in the hydatid cyst from E. Granulosus; necrosis, cavitation, contiguous spread, and death usually ensue. Synonym: multilocular hydatid cyst, multiloculate hydatid cyst. (05 Mar 2000) |
| aneurysmal bone cyst | <radiology> ABC, 10 - 30 yrs, 75% before skeletal maturity, sites: long bones; also, flat bones Findings: metaphyseal if unfused, metaepiphyseal after fusion, lytic, expansile, thin, continuous rim, thin internal bony strands (12 Dec 1998) |
| angioblastic cyst | Mesenchymal tissue capable of forming blood in the embryo. (05 Mar 2000) |
| apical periodontal cyst | An inflammatory odontogenic cyst derived histogenetically from Malassez' epithelial rests surrounding the root apex of a nonvital tooth. Synonym: periapical cyst, radicular cyst, root end cyst. (05 Mar 2000) |
| apoplectic cyst | A pseudocyst formed of extravasated blood as in a stroke. (05 Mar 2000) |
| arachnoid cyst | A fluid-filled cyst lined with arachnoid membrane, frequently situated near the lateral aspect of the fissure of Sylvius; usually congenital in origin. Synonym: leptomeningeal cyst. (05 Mar 2000) |