We report on three adult patients with primary
glioblastomas showing prominent adipocytic (lipomatous) differentiation, hence referred to as "
glioblastomas with adipocyte-like
tumor cell differentiation." Histologically, the
tumors demonstrated typical features of
glioblastoma but additionally contained areas consisting of
glial fibrillary acidic protein (GFAP)-positive astrocytic
tumor cells resembling adipocytes, that is, containing large intracellular
lipid vacuoles. Comparative genomic hybridization (CGH) and focused molecular genetic analyses demonstrated gains of chromosomes 7, losses of chromosomes 9 and 10, as well as homozygous deletion of
p14(ARF) in one of the
tumors. The second
tumor showed gains of chromosomes 3, 4, 8q and 12 as well as losses of chromosomes 10, 13, 15q, 19 and 22. In addition, this
tumor carried homozygous deletions of CDKN2A and
p14(ARF) as well as point mutations in the TP53 and PTEN genes. The third
tumor also had a mutation in the PTEN gene. None of the
tumors demonstrated EGFR, CDK4 or MDM2 amplification. Taken together, our results define a rare
glioblastoma differentiation pattern and indicate that
glioblastomas with adipocyte-like
tumor cell differentiation share common molecular genetic features with other primary
glioblastomas.