| lymphoma, follicular | Malignant lymphoma in which the lymphomatous cells are clustered into identifiable nodules within the lymph nodes. The nodules resemble to some extent the germinal centres of lymph node follicles and most likely represent neoplastic proliferation of lymph node-derived follicular centre B-lymphocytes. This class of lymphoma usually occurs in older persons, is commonly multinodal, and possibly extranodal. Patients whose lymphomas present a follicular or nodular pattern generally have a more indolent course than those presenting with a diffuse pattern. (12 Dec 1998) |
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| lymphoma, high-grade | One of the three major prognostic groupings for non-hodgkin lymphomas as proposed in the working formulation of the non-hodgkin's lymphoma pathologic classification project sponsored by the national cancer institute (1981). Lymphomas falling within this group have a relatively unfavorable survival potential. (12 Dec 1998) |
| lymphoma, intermediate-grade | One of the three major prognostic groupings for non-hodgkin lymphomas as proposed in the working formulation of the non-hodgkin's lymphoma pathologic classification project sponsored by the national cancer institute (1981). Lymphomas falling within this group have an intermediate survival potential. (12 Dec 1998) |
| lymphoma, low-grade | One of the three major prognostic groupings for non-hodgkin lymphomas as proposed in the working formulation of the non-hodgkin's lymphoma pathologic classification project sponsored by the national cancer institute (1981). Lymphomas falling within this group have a relatively favourable survival potential. (12 Dec 1998) |
| lymphoma, lymphoblastic | A high-grade malignant lymphoma composed of a diffuse, relatively uniform proliferation of cells with round or convoluted nuclei and scanty cytoplasm. The cells are cytologically similar to the lymphoblasts seen in acute lymphocytic leukaemia, and in some cases, the disease may evolve into a leukaemic phase morphologically indistinguishable from acute t-lymphocytic leukaemia (leukaemia, T-cell, acute). Lymphoblastic lymphoma represents approximately one-third of the cases of non-hodgkin's lymphomas in children and 5% of the cases in adults. It is more prevalent in males. (12 Dec 1998) |
| lymphoma, mucosa-associated lymphoid tissue | Extranodal lymphoma of lymphoid tissue associated with mucosa that is in contact with exogenous antigens. Many of the sites of these lymphomas, such as the stomach, salivary gland, and thyroid, are normally devoid of lymphoid tissue. They acquire malt tissue as a result of an immunologically mediated disorder. (12 Dec 1998) |
| lymphoma, non-hodgkin | Any of a group of malignant tumours of lymphoid tissue that differ from hodgkin disease, being more heterogeneous with respect to malignant cell lineage, clinical course, prognosis, and therapy. The only common feature among these tumours is the absence of giant reed-sternberg cells, a characteristic of hodgkin's disease. (12 Dec 1998) |
| lymphoma, small lymphocytic | A low-grade malignant lymphoma that may, in some cases, be considered histologically identical to chronic lymphocytic leukaemia (cll; leukaemia, lymphocytic, chronic). It is diffuse in pattern, representing the neoplastic proliferation of well-differentiated B-lymphocytes. In patients with immunoglobulin gammopathies, the lymphocytes may exhibit plasmacytoid characteristics. (12 Dec 1998) |
| lymphoma, undifferentiated | A form of lymphoma in which relatively large stem cells with large nuclei, pale, scanty cytoplasm, and indistinct borders are predominant. The cells are undifferentiated, i.e., show no morphologic evidence of maturation toward lymphocytes or histiocytes. (12 Dec 1998) |
| androgenic zone | A transient adrenocortical zone present in some rodents at birth, most notably in mice, situated between the zona reticularis and the adrenal medulla; it degenerates in males with the secretion at puberty and in females during their first pregnancy; it slowly enlarges in unmated females after puberty and does not degenerate until middle age; the X zone appears to secrete no hormone. Synonym: androgenic zone. Misnomer for the foetal adrenal cortex of primates. Synonym: foetal reticularis. (05 Mar 2000) |
| arcuate zone | The inner third of the basilar membrane of the cochlear duct extending from the tympanic lip of the osseous spiral lamina to the outer pillar cell of the spiral organ (of Corti). Synonym: zona arcuata, zona tecta. (05 Mar 2000) |
| Barnes' zone | The lower fourth of the pregnant uterus, attachment of the placenta to any part of which may cause dangerous haemorrhage. Synonym: cervical zone. (05 Mar 2000) |
| buffer zone | <ecology> An area of land separating two distinct land uses that acts to soften or mitigate the effects of one land use on the other. (09 Oct 1997) |
| capillary zone electrophoresis | A method for separating molecules extremely rapidly based on their electrophoretic mobility. (05 Mar 2000) |
| vascular zone | An area in the external acoustic meatus where a number of minute blood vessels enter from the mastoid bone. Synonym: spongy spot, zona vasculosa. (05 Mar 2000) |