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Pleomorphic
xanthoastrocytoma: what do we really know about it?
Giannini C, Scheithauer BW, Burger PC, Brat DJ, Wollan PC, Lach B, O'Neill BP
Department of Pathology, Mayo Clinic, Rochester, Minnesota 55905,
USA.
Background. Pleomorphic xanthoastrocytomas (PXA) may recur and
demonstrate aggressive clinical behavior with a mortality rate between 15% and
20%.
To the authors' knowledge, no histopathologic features currently are known to
reliably predict recurrence or tumor progression.
Methods.
The study was based on 71 cases with available information regarding clinical
and therapeutic data and follow-up.
Diagnostic features included cellular pleomorphism, giant and/or xanthic cells,
eosinophilic granular bodies, desmoplasia, and leptomeningeal involvement.
The mitotic index (MI), the presence of necrosis, and endothelial proliferation
were recorded in all primary resection specimens.
Results.
The study included 35 females and 36 males, age 26+/-16 years (mean +/- standard
deviation).
Approximately 98% of tumors were supratentorial, with 49% in the temporal
lobe.
Seizures were the presenting symptoms in 71% of patients.
Extent of tumor removal was macroscopic total resection in 68% of cases and
subtotal resection (STR) in 32% of cases.
Postoperative radiotherapy, alone or with chemotherapy, was administered in 29%
and 12.5% of cases, respectively.
The recurrence free survival rates (RFS) were 72% at 5 years and 61% at 10
years, whereas overall survivals rates (OS) were 81% at 5 years and 70% at 10
years.
In univariate analysis, the extent of resection was the single factor associated
most strongly with RFS (P=0.003), followed by MI (P=0.007) and atypical mitoses
(P=0.04).
Necrosis was not found to be significant.
The extent of resection and MI were confirmed as independent predictors of RFS
by multivariate analysis.
MI (P=0.001), atypical mitoses (P=0.02), and necrosis (P=0.04) were associated
with OS by univariate analysis.
In multivariate analysis, only MI was an independent predictor of
survival.
Information regarding MIB-1 labeling index and the use of adjuvant therapy was
too limited to explore their prognostic significance confidently.
Conclusions.
The study confirms that PXA is an astrocytic tumor with a relatively favorable
prognosis.
MI and extent of resection appear to be the main predictors of RFS and OS.
Given the slow growth of the tumor, more studied cases and longer periods of
follow-up will be essential to confirm our findings regarding prognostic factors
affecting this unusual tumor.
PMID: 10223246 [PubMed - indexed for MEDLINE]
Source:
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=10223246&dopt=Abstract
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