Astroblastoma is a distinctive brain tumor when its histologic features occur in 
pure form. More often, the tumor pattern is seen to emerge in infiltrative 
astrocytic tumors. The former are rare. Astroblastoma as a de novo component of 
gliosarcoma has not previously been described. Furthermore, astroblastoma has 
only once been reported to occur in the setting of neurofibromatosis Type I 
(NF1), a condition more often associated with pilocytic and diffuse or 
infiltrative astrocytic tumors. Herein, we describe a unique case of anaplastic 
de novo astroblastoma-sarcoma, in essence a variant of gliosarcoma, occurring in 
a 50-year-old female with documented NF1. Genetic study (fluorescence in situ 
hybridization) demonstrated no chromosomal losses or gains. Testing for 
abnormalities of chromosomes 7, 9, 10, 12, 17, 19 and 20, including the EGFR, 
p16, PTEN, MDM2 and NF1 gene regions, we found the tumor to exhibit a deletion 
of PTEN, monosomy 17 and gains of chromosomes 19 and 20q. The latter 
alterations, having been reported in astroblastoma, were noted in both tumor 
components, thus confirming the common origin of the glial and sarcomatous 
elements.