Modern pathology : an official journal of the United States and Canadian Academy of Pathology, Inc
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Recurrent mutations in the promoter region of telomerase reverse transcriptase (TERT) have been found in various cancers including diffuse gliomas. Mutations lead to TERT upregulation and are associated with aggressive clinical behavior in glioblastomas. However, the clinical significance of TERT promoter mutations in lower-grade gliomas remains undetermined. ⋯ In contrast, among the subset of 74 IDH wild-type lower-grade gliomas with intact 1p/19q, TERT promoter mutation was associated with shorter PFS (P=0.001) and OS (P=0.001). Similarly, in the subset of 65 IDH wild-type astrocytomas, 16 TERT promoter-mutated tumors exhibited unfavorable PFS (P=0.007) and OS (P=0.008). Our results indicate that when combined with IDH status, TERT promoter mutation contributes to prognostic subgroups of lower-grade astrocytic tumors or 1p/19q intact lower-grade gliomas and this may further refine future molecular classification of lower-grade gliomas.
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Cellular schwannoma is an uncommon, but well-recognized, benign peripheral nerve sheath tumor, which can be misdiagnosed as malignant peripheral nerve sheath tumor. To develop consensus diagnostic criteria for cellular schwannoma, we reviewed 115 malignant peripheral nerve sheath tumor and 26 cellular schwannoma cases from two institutions. Clinical data were retrieved from the electronic medical records, and morphologic features, maximal mitotic counts, Ki67 labeling indices, and immunohistochemical profiles (SOX10, SOX2, p75NTR, p16, p53, EGFR, and neurofibromin) were assessed. ⋯ Fourth, Ki-67 labeling indices ≥20% were highly predictive of malignant peripheral nerve sheath tumor (87% sensitivity and 96% specificity). Taken together, the combinations of these histopathological and immunohistochemical features provide useful criteria to distinguish between malignant peripheral nerve sheath tumor and cellular schwannoma with high sensitivity and specificity. Additional retrospective and prospective multicenter studies with larger data sets will be required to validate these findings.