| amelanotic melanoma | <tumour> An anaplastic melanoma consisting of cells derived from melanocytes but not forming melanin. (05 Mar 2000) |
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| amelia | <embryology> The congenital absence of a limb or limbs. (27 Sep 1997) |
| amelioration | Improvement; moderation in the severity of a disease or the intensity of its symptoms. Origin: L. Ad, to, + melioro, to make better (05 Mar 2000) |
| ameloblast | <cell biology> Columnar epithelial cells that secrete the enamel layer of teeth in mammals. Their apical surfaces are tapering Tomes processes) and are embedded within the enamel matrix. (18 Nov 1997) |
| ameloblastic adenomatoid tumour | A benign epithelial odontogenic tumour appearing radiographically as a well-circumscribed radiolucent-radiopaque lesion usually surrounding the crown of an impacted tooth in an adolescent or young adult; characterised histologically by columnar cells organised in a duct-like configuration interspersed with spindle-shaped cells and amyloid-like deposition that gradually undergoes dystrophic calcification. Synonym: adenoameloblastoma, ameloblastic adenomatoid tumour. (05 Mar 2000) |
| ameloblastic fibroma | <tumour> A benign mixed odontogenic tumour characterised by neoplastic proliferation of both epithelial and mesenchymal components of the tooth bud without the production of dental hard tissue; presents clinically as a slow-growing painless radiolucency occurring most commonly in the mandible of children and adolescents. (05 Mar 2000) |
| ameloblastic fibrosarcoma | <tumour> A rapidly growing, painful, destructive, radiolucent odontogenic tumour that usually arises through malignant change in the mesenchymal component of a pre-existing ameloblastic fibroma. Synonym: ameloblastic sarcoma. (05 Mar 2000) |
| ameloblastic layer | The internal layer of the enamel organ. Synonym: enamel layer. (05 Mar 2000) |
| ameloblastic odontoma | <tumour> A benign mixed odontogenic tumour comprised of an undifferentiated component histologically identical to an ameloblastoma and a well differentiated component identical to an odontoma; appears as a mixed radiolucent-radiopaque lesion and presents clinically as an ameloblastoma. Synonym: odontoameloblastoma. (05 Mar 2000) |
| ameloblastic sarcoma | <tumour> A rapidly growing, painful, destructive, radiolucent odontogenic tumour that usually arises through malignant change in the mesenchymal component of a pre-existing ameloblastic fibroma. Synonym: ameloblastic sarcoma. (05 Mar 2000) |
| ameloblastoma | <oncology, tumour> A malignant jaw tumour (adamantinoma) which stems from the ameloblasts, cells which form tooth enamel. (09 Oct 1997) |
| ameloblastomatous craniopharyngioma | <tumour> A form of craniopharyngioma resembling an ameloblastoma. (05 Mar 2000) |
| ameloblasts | Cylindrical epithelial cells in the innermost layer of the enamel organ. Their functions include contribution to the development of the dentinoenamel junction by the deposition of a layer of the matrix, thus producing the foundation for the prisms (the structural units of the dental enamel), and production of the matrix for the enamel prisms and interprismatic substance. (12 Dec 1998) |
| amelodental junction | Amelodentinal junction, rarely used terms for dentinoenamel junction. (05 Mar 2000) |
| amelodentinal | Relating to the dentin and enamel of teeth. Synonym: amelodentinal. (05 Mar 2000) |