fibrillary astrocytoma


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Related to fibrillary astrocytoma: protoplasmic astrocytoma

fi·bril·lar·y as·tro·cy·to·ma

astrocytoma derived from fibrillary astrocytes.

fibrillary astrocytoma

A relatively slow growing astrocytoma histologically composed of cells with many fibrils. It usually is found in adolescents and young adults. Although its cells are moderately well differentiated, they tend to invade neighboring tissues.
See also: astrocytoma
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We now demonstrate that [Beta]III is a potential marker of high-grade astrocytomas, and its expression may also define incipient anaplastic phenotypes in diffuse fibrillary astrocytomas.
The cases were grouped into high-grade astrocytomas (consisting of anaplastic astrocytoma, WHO grade 3, and glioblastoma multiforme, WHO grade 4); diffuse fibrillary astrocytomas (including gemistocytic astrocytomas, WHO grade 2); and pilocytic astrocytomas (WHO grade 1).
In diffuse fibrillary astrocytomas, the distribution of [Beta]III immunoreactivity was also substantially less than that in high-grade astrocytomas (MLI, 4%; IQR, 0.2%-21%) (P [is less than] .0001) (Figure 1).
The Ki-67 MLI for high-grade astrocytomas, WHO grades 3 and 4 combined, was 24% (IQR, 17%-25%) (P [is less than] .002 vs diffuse fibrillary astrocytomas; P [is less than] .0001 vs pilocytic astrocytomas).
When the tumor grade is taken into consideration, 7 (13.2%) cases were pilocytic astrocytomas (WHO grade I), 22 (43.1%) cases were fibrillary astrocytomas (WHO grade II), 6 (11.8%) cases were anaplastic astrocytomas (WHO grade III) and 16 (31.4%) cases were glioblastomas (WHO grade IV).