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Abstract:
Background The most common chromosomal aberration found in meningiomas is
monosomy 22. Progression and recurrence of meningiomas are usually associated
with additional chromosome losses. Rarely, however, meningiomas have strongly
hyperdiploid karyotypes with over 50 chromosomes; the objective of this study
was to explore the cytogenetic and histopathologic patterns as well as the
clinical significance of hyperdiploidy in meningiomas.
Methods Within a series of 677 consecutive meningiomas, we identified a
subgroup comprising 16 cases that display a strikingly uniform pattern of
hyperdiploidy mostly without structural chromosome rearrangements, as shown by
banding techniques and, in the single structurally aberrant case, spectral
karyotyping.
Results These meningiomas each have between 50 and 56 chromosomes, with
trisomy 12 (14/16 cases), trisomy 20 (13/16 cases), trisomy 5 (12/16 cases),
and trisomy 17 (10/16 cases). Histomorphologically, hyperdiploid meningiomas
feature a heterogeneous phenotype. However, they are associated with a higher
histological grade, and decreased expression of alkaline phosphatase as
compared to meningiomas with typical karyotype. In two patients, recurrences
were documented and three patients died of disease during the period of
observation, indicating a worse prognosis of hyperdiploid than of
cytogenetically typical meningiomas.
Conclusion We conclude that hyperdiploidy constitutes a small but clinically
relevant entity of biologically aggressive meningiomas, which are
cytogenetically distinguishable from the majority of common-type meningiomas.
